2016 American Thyroid Association (ATA) Guidelines for Diagnosis and Management of Hyperthyroidism and Other Causes of Thyrotoxicosis (Ross et al., Thyroid 2016;26:1343–1421)

Definition & Overview

1.1 Key Terminology

• Thyrotoxicosis: clinical state from inappropriately HIGH thyroid hormone action in tissues, from ANY cause.
• Hyperthyroidism: a subtype of thyrotoxicosis caused by excess thyroid hormone SYNTHESIS and SECRETION by the thyroid itself (e.g., Graves’, TMNG, TA). Not all thyrotoxicosis is hyperthyroidism (e.g., thyroiditis, factitious ingestion release preformed/exogenous hormone, not synthesis).
• Overt hyperthyroidism: subnormal (usually undetectable) TSH + elevated free T4 and/or T3.
• Subclinical hyperthyroidism (SH): low/undetectable TSH with NORMAL free T4 and normal total/free T3.
• T3-toxicosis: early/mild hyperthyroidism — normal free T4, elevated T3, low/undetectable TSH. Seen early in Graves’ or toxic adenoma.

1.2 Epidemiology

• U.S. prevalence of hyperthyroidism ~1.2% (0.5% overt + 0.7% subclinical).
• Graves’ disease (GD) is the most common cause of hyperthyroidism in the U.S.
• Toxic multinodular goiter (TMNG) prevalence rises with age and in iodine-deficient regions — may exceed GD in older patients.

✦  CLINICAL PEARLS Pearl 1: “Hyperthyroidism” and “thyrotoxicosis” are NOT synonyms. Get the etiology right before picking a drug — ATDs work for hormone OVERPRODUCTION (Graves, TMNG, TA), not for thyroiditis (a hormone-RELEASE problem where ATDs do nothing).

Etiology & Differential Diagnosis

2.1 Mechanistic Classification (4 general mechanisms)

• Excess trophic (TSH-receptor) stimulation — Graves’ disease (TRAb-mediated), TSH-secreting pituitary adenoma, hCG-mediated (molar pregnancy, choriocarcinoma, hyperemesis gravidarum).
• Autonomous thyroid hormone synthesis/release — toxic adenoma (TA), toxic multinodular goiter (TMNG), activating TSH-receptor germline mutations (familial nonautoimmune hyperthyroidism).
• Passive release of preformed hormone from an inflamed/damaged gland (destructive thyroiditis) — subacute (de Quervain’s), painless (silent)/postpartum, palpation, acute (infectious) thyroiditis, amiodarone type 2.
• Extrathyroidal hormone exposure — factitious ingestion (thyrotoxicosis factitia), struma ovarii, functioning metastatic follicular thyroid cancer.

2.2 Differential Diagnosis by Radioactive Iodine Uptake (RAIU) — ATA Table 3

Elevated / Normal RAIU (hyperthyroidism — hormone overproduction)	Near-Absent RAIU (thyrotoxicosis without overproduction)
Graves’ disease	Painless (silent) thyroiditis / postpartum thyroiditis
Toxic adenoma (TA) or toxic multinodular goiter (TMNG)	Amiodarone-induced thyroiditis (type 2)
Trophoblastic disease (hCG-mediated)	Subacute (granulomatous, de Quervain’s) thyroiditis
TSH-producing pituitary adenoma	Palpation thyroiditis (post-manipulation/surgery)
Resistance to thyroid hormone (THRB gene mutation)	Factitious ingestion of thyroid hormone
	Struma ovarii
	Acute (infectious) thyroiditis
	Extensive functioning metastases from follicular thyroid cancer

Note: iodine-induced/iodine-exposed hyperthyroidism (including amiodarone type 1) may show LOW uptake despite being a true overproduction state — uptake alone can mislead if there was recent iodine/contrast exposure.

2.3 Quick Diagnostic Clues to Distinguish Etiologies

Feature	Graves’ disease	TMNG / TA	Destructive thyroiditis	Factitious ingestion
Goiter	Diffuse, symmetric ± bruit	Nodular, asymmetric	Absent-to-mild, may be tender (subacute)	Absent; small gland
Eye disease (GO)	Common	Absent	Absent	Absent
TRAb / TSI	Positive (96–97% sens, 99% spec)	Negative	Negative	Negative
RAIU	High	High/normal	Near-zero	Near-zero
T3:T4 ratio (ng/µg)	High, typically >20	High, >20	Low, <20	Low <20 (if exogenous LT4)
Thyroglobulin	Detectable/↑	Detectable/↑	Detectable/↑ (released with hormone)	Suppressed/low
ESR	Normal	Normal	↑↑ in subacute (often >50, up to >100 mm/h)	Normal

⚠  PHARMACIST WATCHOUT If a patient presents with thyrotoxicosis and a SUPPRESSED thyroglobulin + near-zero RAIU + no goiter → think factitious ingestion (surreptitious levothyroxine/liothyronine, or over-the-counter “thyroid support” or weight-loss supplements). Ask about supplement use directly during medication reconciliation — this is a classic pharmacist catch.A disproportionately elevated T3 relative to T4 in a patient on presumed “LT4-only” therapy suggests co-ingestion of liothyronine (T3) or desiccated thyroid/combination products — review OTC and compounded product use.

Signs & Symptoms of Thyrotoxicosis

3.1 General Approach

All patients should undergo a comprehensive history/physical: pulse, BP, respiratory rate, weight; thyroid size/tenderness/symmetry/nodularity; pulmonary, cardiac, neuromuscular exam; peripheral edema, eye signs, pretibial myxedema.

3.2 Symptom & Sign Clusters

System	Common findings
Adrenergic / General	Heat intolerance, diaphoresis, weight loss despite ↑appetite, tremor, anxiety, insomnia, fatigue
Cardiovascular	Tachycardia, palpitations, widened pulse pressure, atrial fibrillation (especially elderly), systolic HTN, high-output heart failure in severe/prolonged disease
Neuromuscular	Proximal muscle weakness, hyperreflexia, fine tremor
GI	Increased bowel frequency/hyperdefecation, occasionally nausea/vomiting/diarrhea in severe disease
Dermatologic	Warm moist skin, hair thinning, onycholysis; pretibial myxedema — specific to GD
Reproductive	Oligomenorrhea/amenorrhea, decreased fertility, gynecomastia (men)
Ocular (Graves’ only)	Periorbital edema, lid retraction/lag, proptosis, diplopia, chemosis — seen only with Graves’ orbitopathy (GO), present in up to ~1/3 of GD patients (5% moderate-severe)
Psychiatric	Emotional lability, anxiety, occasionally frank psychosis in severe thyrotoxicosis/storm

3.3 Elderly / “Apathetic” Presentation

• Older patients may present atypically — blunted adrenergic symptoms, predominant weight loss, atrial fibrillation, or unexplained heart failure (“apathetic hyperthyroidism”). Have a lower threshold to check TSH in elderly patients with new AF or unexplained weight loss.

✦  CLINICAL PEARLS Pearl 2: New-onset atrial fibrillation in a patient >60 years old = check TSH. Subclinical hyperthyroidism alone (TSH <0.1 mU/L) carries a ~2.8-fold increased AF risk in this age group and is a guideline-endorsed indication to treat even without overt disease.

Diagnostic Work-Up

4.1 Biochemical Evaluation (Recommendation 1–2)

• Serum TSH = most sensitive/specific single initial screening test. Because of the log-linear TSH/fT4 relationship, small fT4 changes cause LARGE TSH swings.
• When thyrotoxicosis is strongly suspected: check TSH + free T4 + total T3 together at initial evaluation (do not rely on TSH alone).
• Overt hyperthyroidism: ↓ TSH (usually <0.01 mU/L) + ↑ fT4 and/or T3.
• Mild/early disease (“T3-toxicosis”): normal fT4, isolated ↑T3, low/undetectable TSH.
• Subclinical hyperthyroidism: ↓ TSH with NORMAL fT4 and T3.

4.2 Etiology Work-Up (Recommendation 1)

• If clinical picture is classic for Graves’ (diffuse goiter + recent orbitopathy + mod-severe thyrotoxicosis) — no further etiology testing needed.
• Otherwise: measure TRAb (TSH-receptor antibody) OR obtain RAIU, OR assess thyroidal blood flow via Doppler ultrasound.
• Obtain a 123I or 99mTc pertechnetate scan when the clinical picture suggests TA or TMNG (nodular gland).
• TRAb positive → confirms Graves’ (most common cause) with 96–97% sensitivity / 99% specificity (third-generation assays). TRAb negative does NOT rule out mild GD.
• If third-generation TRAb assay unavailable → RAIU is the preferred alternative.

Choosing the test with an eye toward treatment (pharmacist-relevant nuance)

• If the patient is leaning toward MMI with a remission goal → checking baseline TRAb is useful (predicts remission likelihood at drug discontinuation).
• If the patient is leaning toward RAI → obtaining RAIU serves dual purpose: diagnosis AND RAI dose calculation.

4.3 Ratio & Ancillary Tests

• Total T3:T4 ratio (ng/µg): >20 favors true hyperthyroidism (GD, TMNG/TA); <20 favors destructive thyroiditis or factitious ingestion (exogenous LT4).
• Thyroglobulin: detectable/elevated in thyroiditis (hormone released along with Tg); SUPPRESSED in factitious ingestion (exogenous hormone suppresses endogenous Tg release).
• Color-flow Doppler ultrasound: increased vascularity/flow = hyperactive gland (GD); decreased flow = destructive thyroiditis. Useful when RAI/scintigraphy contraindicated (pregnancy, breastfeeding).
• ESR: markedly elevated (often >50, sometimes >100 mm/h) in subacute thyroiditis; helps distinguish from painless thyroiditis.

4.4 Pre-Analytic Pitfalls Pharmacists Should Recognize

⚠  PHARMACIST WATCHOUT Biotin (high-dose supplements, common in “hair/skin/nail” products): can cause spuriously LOW TSH and spuriously HIGH free T4 in streptavidin-biotin immunoassays, mimicking hyperthyroidism. Advise holding biotin ≥2 days before repeat labs if suspected.Heterophilic/anti-mouse antibodies can cause spurious TSH results — confirm with repeat assay, serial dilution, or direct anti-mouse antibody testing if the picture doesn’t fit.Heparin therapy can cause spuriously elevated free T4 via in-vitro lipoprotein lipase activation releasing free fatty acids that displace T4 from binding proteins.Amiodarone and high-dose propranolol inhibit T4→T3 conversion and can cause “euthyroid hyperthyroxinemia” (↑T4 without true thyrotoxicosis) — don’t treat the number, treat the patient + TSH pattern.Pregnancy, acute psychiatric illness, extreme high altitude, and amphetamine use are other non-thyroidal causes of euthyroid hyperthyroxinemia.

Risk Stratification & Severity Grading

5.1 Grading Biochemical Severity (guides initial ATD dose — see Section 7)

Severity (by free T4)	Rough initial MMI dose
Free T4 1–1.5x ULN (mild)	5–10 mg/day
Free T4 1.5–2x ULN (moderate)	10–20 mg/day
Free T4 2–3x ULN (severe)	30–40 mg/day

These are rough guides to be tailored to symptoms, goiter size, and total T3 level (ATA text under Recommendation 13).

5.2 Thyroid Storm — Burch–Wartofsky Point Scale (BWPS)

Thyroid storm is a CLINICAL diagnosis in a severely thyrotoxic patient with systemic decompensation; the BWPS is an adjunctive scoring tool (Recommendation 34).

Domain	Finding	Points
Thermoregulatory (°F)	99.0–99.9 / 100–100.9 / 101–101.9 / 102–102.9 / 103–103.9 / ≥104.0	5 / 10 / 15 / 20 / 25 / 30
CNS disturbance	Absent / Mild (agitation) / Moderate (delirium, psychosis, extreme lethargy) / Severe (seizure, coma)	0 / 10 / 20 / 30
GI-hepatic dysfunction	Absent / Moderate (diarrhea, abd. pain, N/V) / Severe (jaundice)	0 / 10 / 20
Tachycardia (bpm)	100–109 / 110–119 / 120–129 / 130–139 / ≥140	5 / 10 / 15 / 20 / 25
Atrial fibrillation	Absent / Present	0 / 10
Congestive heart failure	Absent / Mild / Moderate / Severe	0 / 5 / 10 / 20
Precipitant history	Positive / Negative	0 / 10

Total score	Interpretation
≥45	Thyroid storm — aggressive therapy indicated
25–44	Impending storm — aggressive therapy per clinical judgment (do not overtreat based on score alone)
<25	Storm unlikely

✖  RED FLAG / URGENT BWPS ≥45, OR JTA TS1/TS2 with systemic decompensation → activate multimodality thyroid storm protocol immediately (Section 9). Mortality 8–25% even in modern series.Common precipitants: abrupt ATD discontinuation, thyroid or non-thyroidal surgery in inadequately treated thyrotoxicosis, infection/acute illness, parturition, and occasionally RAI therapy itself.

5.3 Subclinical Hyperthyroidism — When to Treat (ATA Table 10)

Risk factor	TSH <0.1 mU/L	TSH 0.1–0.4 mU/L
Age ≥65 years	Treat	Consider treating
Cardiac disease	Treat	Consider treating
Osteoporosis	Treat	Consider treating
Postmenopausal, not on estrogen/bisphosphonate	Treat	Consider treating
Hyperthyroid symptoms present	Treat	Consider treating
Age <65, asymptomatic	Consider treating	Observe

5.4 Graves’ Orbitopathy (GO) — Activity & Severity

Clinical Activity Score (CAS) — 1 point each, active if CAS ≥3

• Retro-orbital pain (past 4 weeks); pain with eye movement
• Eyelid redness/swelling; conjunctival redness/chemosis; caruncle swelling
• ↑ Proptosis ≥ 2 mm; ↓ eye movement ≥5°; ↓ visual acuity ≥1 line (Snellen) — these 3 require prior comparison

Severity grading

Grade	Key features
Mild	Lid retraction <2mm, mild soft tissue involvement, proptosis <3mm, transient/absent diplopia, no corneal exposure
Moderate–severe	Lid retraction ≥2mm, moderate–severe soft tissue involvement, proptosis ≥3mm, inconstant/constant diplopia, mild corneal exposure
Sight-threatening	Dysthyroid optic neuropathy and/or severe corneal breakdown — requires IMMEDIATE intervention

GO risk factors (ATA Table 15)

• Non-modifiable: older age, female sex (though more severe in men), Caucasian ancestry, high TRAb titer (>8.8 IU/L = high risk)
• Modifiable: SMOKING (single most important modifiable risk factor), RAI therapy itself (risk additive to smoking, preventable with steroid coverage), poorly controlled thyroid dysfunction

✦  CLINICAL PEARLS Pearl 3: Smoking cessation counseling belongs in EVERY Graves’ disease medication review — it is the single most important modifiable risk factor for orbitopathy onset/progression and reduces the efficacy of GO-directed therapy.

Genetics / Molecular Basis (brief)

The ATA guideline addresses genomics only briefly; the following reflects what is explicitly stated in the guideline text.

• Graves’ disease: autoimmune disorder — thyrotropin receptor antibodies (TRAb/TSI) bind and STIMULATE the TSH receptor, driving hormone overproduction. Not a somatic mutation disorder.
• Toxic adenoma: caused by somatic ACTIVATING mutations in genes regulating thyroid growth and hormone synthesis (most commonly TSHR, occasionally GNAS).
• Familial nonautoimmune hyperthyroidism: caused by GERMLINE activating mutations in the TSH receptor gene — presents as sporadic or familial diffuse goiter with hyperthyroidism, TRAb-negative.
• Resistance to thyroid hormone: due to mutations in the thyroid hormone receptor-β (THRB) gene; suspect when thyroid hormone is elevated but TSH is normal/elevated (not suppressed) — confirmed with family history + genetic testing.
• TSH-secreting pituitary adenoma: elevated thyroid hormone with inappropriately normal/elevated TSH; supported by a disproportionately high pituitary glycoprotein α-subunit:TSH ratio and pituitary MRI findings.

⚠  PHARMACIST WATCHOUT “Elevated thyroid hormone + NON-suppressed TSH” is NOT typical Graves’/TMNG/TA (which suppress TSH). This pattern should trigger a workup for TSH-secreting adenoma or thyroid hormone resistance, not an automatic increase in ATD dose.

Pharmacotherapy: Antithyroid Drugs (ATDs)

7.1 Mechanism & Agents

• Methimazole (MMI): inhibits thyroid peroxidase → blocks new hormone synthesis. Once-daily dosing. Preferred first-line ATD (Recommendation 12) except in 1st-trimester pregnancy and thyroid storm (where PTU’s additional T4→T3 blockade is used).
• Propylthiouracil (PTU): blocks new hormone synthesis AND peripheral T4→T3 conversion. Shorter half-life → divided dosing (2–3x/day). Reserved for: 1st trimester pregnancy, thyroid storm, MMI intolerance/minor reaction (with caution), or breastfeeding second-line.
• Carbimazole: prodrug converted to MMI (10 mg carbimazole ≈ 6 mg MMI); used in place of MMI in some countries.

7.2 Dosing Table

Drug	Starting dose (adult)	Maintenance dose	Notes
Methimazole (MMI)	5–10 mg/d (mild); 10–20 mg/d (moderate); 30–40 mg/d (severe) — titrate to fT4	5–10 mg/d once symptoms/labs normalize	Split dosing (e.g., 15–20mg BID) may work faster in severe disease; once-daily generally adequate
PTU	50–150 mg TID (severity-based)	50 mg BID–TID	Reserve for 1st trimester, thyroid storm, or MMI-allergic patients
Pediatric MMI	0.2–0.5 mg/kg/d (range 0.1–1.0 mg/kg/d); by age: infants 1.25mg/d; 1–5y 2.5–5mg/d; 5–10y 5–10mg/d; 10–18y 10–20mg/d	Reduce by ≥50% once euthyroid	Avoid PTU in children (hepatotoxicity risk); avoid initial doses >30mg in adolescents/adults

✖  RED FLAG / URGENT “Block-and-replace” (continuous high-dose ATD + levothyroxine) is NOT recommended — higher rate of ATD adverse effects with no efficacy benefit. Flag this combination during medication review as a likely error or outdated regimen.

7.3 Baseline & Ongoing Monitoring

• Baseline (before starting ATD): CBC with differential (WBC) + liver profile (bilirubin, transaminases) — Recommendation 15 (weak; low-quality evidence).
• Counsel EVERY patient in writing before starting and at each visit (Recommendation 14, strong): STOP the drug immediately and call the physician for sore throat/fever/mouth sores (possible agranulocytosis) or jaundice/dark urine/pale stool/abdominal pain/nausea/fatigue (possible hepatotoxicity).
• Routine WBC/LFT monitoring during therapy: NOT proven to reliably predict/prevent agranulocytosis (onset is often abrupt) — no consensus recommendation either way (Recommendations 18–19). Symptom-triggered testing is the mainstay.
• Thyroid function monitoring: fT4/T3/TSH every 2–6 weeks initially, then every 4–6 weeks until stable; TSH may remain suppressed for months and is NOT a reliable early monitoring parameter — trend fT4/T3, not TSH, early in therapy.
• Check serum T3 in addition to fT4 — some patients normalize fT4 on MMI but have persistently elevated T3 (ongoing thyrotoxicosis).

7.4 Major Adverse Effects

Agranulocytosis

• Incidence ~0.1–0.5%; most occurs within the FIRST 90 DAYS of therapy (median onset ~36–38 days for both MMI and PTU).
• Dose-related for MMI — higher initial doses (e.g., 30mg vs 15mg/d) carry higher risk.
• No reliable predictive risk factors identified; a substantial proportion had a NORMAL WBC within 1–2 weeks before onset — routine screening has limited sensitivity for catching it early.
• Cross-reactivity between MMI and PTU exists — switching drugs after agranulocytosis is generally CONTRAINDICATED (exception: brief, life-threatening thyroid storm scenarios, per clinical judgment).

Hepatotoxicity

• MMI: classically cholestatic pattern (though hepatocellular injury reported too).
• PTU: can cause FULMINANT hepatic necrosis — potentially fatal; liver transplant reported. FDA issued a black-box-type safety alert in 2010; children are especially susceptible — PTU is generally AVOIDED in pediatric patients except brief 1st-trimester-equivalent scenarios.
• PTU hepatotoxicity typically occurs after a median of ~120 days of therapy.
• Hyperthyroidism itself can mildly elevate LFTs in up to 30% of untreated patients — distinguishing drug effect from disease effect requires prospective follow-up/trend.

Other reactions

• Minor cutaneous reactions (pruritus, rash): manage with concurrent antihistamine WITHOUT stopping the ATD (Recommendation 20).
• Persistent/symptomatic minor reactions: stop ATD, switch to the OTHER ATD (if not RAI/surgery candidate) or pursue RAI/surgery. For a SERIOUS allergic reaction, do NOT try the alternate ATD.
• PTU-associated ANCA-positive vasculitis: polyarthritis, purpuric skin lesions, occasionally pulmonary/renal involvement; can occur after months–years of therapy; usually resolves with discontinuation, occasionally needs immunosuppression.

⚠  PHARMACIST WATCHOUT Any patient on MMI or PTU presenting with sore throat, fever, or mouth ulcers = hold the ATD and get a STAT CBC with differential before the next dose. Treat as agranulocytosis until proven otherwise.Any patient on MMI or PTU with jaundice, dark urine, pale stool, pruritus, or new abdominal pain/nausea = hold the ATD and check LFTs/bilirubin immediately (Recommendation 18).PTU carries the FDA hepatotoxicity boxed warning — reserve for 1st-trimester pregnancy, thyroid storm, or documented MMI intolerance; avoid in children.Do NOT rely on TSH to judge early ATD response — it can remain suppressed for months after fT4/T3 normalize; trend fT4/T3 instead.

7.5 Duration of ATD Therapy & Discontinuation

• If MMI is primary therapy for Graves’: continue ~12–18 months, then STOP if TSH and TRAb are normal at that time (Recommendation 22, strong; high-quality evidence).
• Check TRAb prior to stopping ATD — a normal TRAb predicts a greater chance of remission (Recommendation 21).
• Remission = normal TSH, fT4, and T3 for 1 year after ATD discontinuation.
• If hyperthyroidism recurs after a full course of MMI — consider RAI or thyroidectomy; continued low-dose MMI beyond 12–18 months is a reasonable alternative for patients preferring to avoid definitive therapy (Recommendation 23, weak).
• ATDs do NOT induce remission in TMNG/TA (non-autoimmune) — relapse is expected on discontinuation; long-term low-dose MMI (usually 5–10mg/d) may be appropriate in poor surgical/RAI candidates.

✦  CLINICAL PEARLS Pearl 4: Two consecutive normal thyroid panels at least 1 month apart, without a therapy change, are needed to confidently call a patient “euthyroid” — a single normal draw can be misleading, especially early in treatment or around dose changes.Pearl 5: Potassium iodide (KI) 38mg + MMI 15mg was shown in an RCT to control hyperthyroidism better with FEWER adverse reactions than MMI 30mg alone in moderate–severe Graves’ — a useful adjunct concept to recognize on rounds, though not yet a routine first-line regimen.

Beta-Adrenergic Blockade (Symptom Control — All Etiologies)

Recommended for ALL symptomatic thyrotoxic patients, especially elderly patients or those with resting HR >90 bpm or coexisting cardiovascular disease (Recommendation 2, strong; moderate-quality evidence). Beta-blockade is appropriate across virtually ALL causes of thyrotoxicosis, unlike ATDs which only work for true hormone overproduction.

Drug	Dose	Frequency	Key considerations
Propranolol	10–40 mg	3–4x/day	Non-selective; longest clinical experience; blocks T4→T3 conversion at high doses; PREFERRED agent in pregnancy/nursing
Atenolol	25–100 mg	1–2x/day	Relative β1-selectivity; better compliance; AVOID in pregnancy; avoid in breastfeeding (accumulates in milk, low renal clearance in infant)
Metoprolol	25–50 mg	2–3x/day	Relative β1-selectivity; safe in breastfeeding (low milk transfer)
Nadolol	40–160 mg	1x/day	Non-selective; once-daily convenience; least clinical experience
Esmolol	50–100 µg/kg/min IV infusion	ICU setting	For severe thyrotoxicosis/thyroid storm; titratable, short half-life

⚠  PHARMACIST WATCHOUT None of the available beta-blockers has FDA approval specifically FOR thyrotoxicosis — this is guideline-supported off-label use; verify institutional formulary status doesn’t block use.β-blockers at guideline doses are NOT sufficiently β1-selective to be considered safe in bronchospastic (active) asthma — generally contraindicated there. In QUIESCENT reactive airway disease, a relative β1-selective agent (atenolol/metoprolol) may be used cautiously with close pulmonary monitoring.Atenolol should be AVOIDED in breastfeeding mothers (highly unbound, low infant renal clearance → neonatal beta-blockade symptoms); propranolol and metoprolol are preferred in lactation.As thyroid function normalizes post-RAI/on ATDs, TAPER the beta-blocker in parallel — don’t leave patients on standing high-dose beta-blockade once they’re euthyroid.

Radioactive Iodine (RAI/¹³¹I) Therapy

9.1 Choosing & Preparing for RAI (Graves’ disease)

• Goal: deliberately render the patient HYPOTHYROID (not “euthyroid” — partial dosing has high failure/retreatment rates).
• Contraindications: pregnancy, lactation, coexisting/suspected thyroid cancer, inability to comply with radiation safety precautions; use with informed caution if planning pregnancy within 4–6 months.
• Pregnancy test required within 48 hours prior to RAI in any woman of childbearing potential — the TREATING physician must verify a negative result personally (Recommendation 9, strong).
• Beta-blockade should be considered even in asymptomatic elderly/comorbid patients before RAI, due to risk of transient post-RAI hormone surge (Recommendation 4).
• MMI pretreatment considered in patients at increased risk of complications from worsening hyperthyroidism (elderly, cardiac disease); discontinue MMI 2–3 days before RAI (prevents blunting of RAI uptake); may resume 3–7 days after RAI in high-risk patients, then taper as thyroid function normalizes.
• Avoid iodine-containing supplements/seaweed for ≥ 7 days before RAI; a low-iodine diet may help in patients with low baseline RAIU.

9.2 Dosing

• Typical single-application mean dose: 10–15 mCi (370–555 MBq) for GD (Recommendation 8, strong; moderate-quality evidence) — low-activity dosing (<10 mCi) has unacceptably high failure/retreatment rates and is not generally recommended.
• Activity may be a fixed dose OR calculated from gland size/uptake (activity [µCi] = gland weight [g] × 50–200 µCi/g ÷ [24h uptake %]); calculation-based dosing has not been shown superior to fixed dosing.
• >150 µCi/g needed to reliably achieve hypothyroidism.

9.3 Follow-Up After RAI

• Check fT4, T3, TSH within 1–2 months post-RAI, then every 4–6 weeks for up to 6 months or until hypothyroid and stabilized on LT4 (Recommendation 11).
• 40% hypothyroid by 8 weeks; >80% by 16 weeks — timing of LT4 initiation is guided by labs/symptoms, not a fixed calendar.
• Taper beta-blockers as fT4/T3 normalize; taper MMI in parallel if it was resumed post-RAI.

9.4 Reproductive Timing

• Women: delay conception until stable euthyroidism on LT4 replacement — typically 4–6 months (or longer) after RAI.
• Men: delay conception attempts 3–4 months post-RAI (allows turnover of sperm production).
• Breastfeeding women: RAI should NOT be given for at least 6 weeks after lactation stops (3 months more reliably ensures normalized breast sodium-iodide symporter activity); breastfeeding should NOT resume after RAI.

9.5 RAI for TMNG / Toxic Adenoma

• Effective, relatively safe option; young/middle-aged patients generally do not need ATD pretreatment.
• If ATD pretreatment IS used, avoid giving RAI while TSH is normal/elevated (increases risk of hypothyroidism from irradiating normal perinodular tissue) UNLESS volume reduction is the specific goal.

✖  RED FLAG / URGENT RAI is CONTRAINDICATED in active, moderate-to-severe or sight-threatening Graves’ orbitopathy — surgery or ATDs are preferred there (Recommendation 107, strong).In patients with mild active GO and risk factors for deterioration (high TRAb, smoker) who receive RAI — concurrent glucocorticoid coverage is RECOMMENDED (Recommendation 106); typical regimen: prednisone 0.4–0.5 mg/kg/day starting 1–3 days post-RAI, continued 1 month, tapered over 2 months (or lower-dose ~0.2–0.3 mg/kg/day x 6 weeks per newer data).

⚠  PHARMACIST WATCHOUT Radiation safety counseling is a pharmacist touchpoint: avoid close/prolonged contact with pregnant women and young children for a defined period post-dose per institutional/NRC guidance; the treating physician must document that public radiation exposure limits are met before discharge.Watch for a drug interaction/administration-sequence issue: iodinated contrast (CT with contrast) or amiodarone exposure in the weeks before planned RAI can blunt uptake and cause treatment failure — flag recent imaging/amiodarone history before RAI is scheduled.

Surgery (Thyroidectomy)

10.1 Indications Favoring Surgery

• Large goiter (≥80g) with compressive symptoms; suspected/confirmed malignancy; large or indeterminate nodules (especially >4cm); coexisting hyperparathyroidism requiring surgery; very high TRAb; moderate–severe active GO; women planning pregnancy <6 months who need rapid definitive control.

10.2 Preoperative Pharmacotherapy Preparation

• Render the patient EUTHYROID with MMI before elective thyroidectomy whenever possible (reduces thyroid storm risk from surgical stress).
• Preoperative potassium iodide (SSKI or Lugol’s solution) in most GD patients — decreases thyroid vascularity/blood flow and intraoperative blood loss.
• Dosing: Lugol’s solution 5–7 drops (0.25–0.35mL; 8mg iodide/drop) TID, OR SSKI 1–2 drops (0.05–0.1mL; 50mg iodide/drop) TID, mixed in water/juice, for 10 days before surgery.
• Rapid preparation for EMERGENT surgery can use corticosteroids ± cholestyramine in addition to standard measures.
• Refer to a HIGH-VOLUME thyroid surgeon (>25 thyroidectomies/year) — complication rates are ~51% higher with low-volume surgeons.

10.3 Postoperative Care

• Monitor for hypocalcemia (transient or permanent hypoparathyroidism), RLN injury (temporary/permanent), bleeding, and anesthesia-related complications.
• Calcium management strategies: measure serum calcium ± intact PTH postoperatively and supplement oral calcium ± calcitriol based on results, OR give prophylactic calcium ± calcitriol empirically.
• Low postop intact PTH (<10–15 pg/mL) predicts symptomatic hypocalcemia and need for calcium/calcitriol supplementation.
• Preoperative oral calcium (e.g., 1g calcium carbonate TID x 2 weeks pre-op) and correcting vitamin D deficiency preoperatively can reduce postoperative hypocalcemia.
• After lobectomy for toxic adenoma: check TSH/fT4 at 4–6 weeks; ~15–20% will need LT4 replacement; calcium monitoring NOT needed after lobectomy (only after near-total/total thyroidectomy).
• Permanent hypoparathyroidism <2% and permanent RLN injury <1% in high-volume-surgeon series.

⚠  PHARMACIST WATCHOUT Postoperative numbness/tingling around the mouth or fingertips (perioral/digital paresthesia), or a positive Chvostek/Trousseau sign = check ionized calcium and PTH urgently — classic hypocalcemia from parathyroid injury/stunning.New hoarseness or voice change post-thyroidectomy = possible RLN injury — flag for ENT/surgical evaluation, and reassess aspiration risk before resuming oral medications/diet.Persistent/recurrent hyperthyroidism after inadequate surgery is generally treated with RAI, not repeat surgery (repeat surgery carries much higher complication risk) — recognize this as the expected next step, not a surgical failure requiring immediate reoperation.

✦  CLINICAL PEARLS Pearl 6: Thyroidectomy timing in pregnancy: SECOND trimester is optimal if surgery is truly needed — first trimester carries higher miscarriage risk (anesthetic teratogenicity concerns), third trimester carries higher preterm labor risk (4.5–5.5% even in 2nd trimester surgery).

Thyroid Storm — Multimodality Emergency Management

Treatment strategy targets 5 fronts simultaneously (Recommendation 35, strong): (i) block hormone synthesis, (ii) block hormone release, (iii) block peripheral T4→T3 conversion / hormone action, (iv) treat systemic decompensation, and (v) treat the precipitating illness.

11.1 Drug Doses — ATA Table 7

Drug	Dosing	Comment
Propylthiouracil	500–1000 mg LOAD, then 250 mg every 4 hours	Blocks new hormone synthesis AND blocks T4→T3 conversion (preferred over MMI in storm); may be given IV
Methimazole	60–80 mg/day (divided)	Blocks new hormone synthesis only — use if PTU unavailable/contraindicated
Propranolol	60–80 mg every 4 hours	Blocks T4→T3 conversion at high doses; consider invasive monitoring if CHF present; alternative: esmolol infusion
Iodine (SSKI)	5 drops (0.25mL / 250mg) PO every 6 hours	MUST start ≥ 1 hour AFTER the ATD dose (never before) — blocks new synthesis + blocks hormone release; alternative: Lugol’s solution
Hydrocortisone	300 mg IV load, then 100 mg IV every 8 hours	May block T4→T3 conversion; provides prophylaxis against relative adrenal insufficiency of severe thyrotoxicosis; alternative: dexamethasone

✖  RED FLAG / URGENT SEQUENCING IS CRITICAL: give the ATD (PTU or MMI) BEFORE iodine (SSKI/Lugol’s). Giving iodine first supplies substrate the still-active gland can use to make MORE hormone, worsening thyrotoxicosis (Wolff-Chaikoff escape risk). Wait ≥ 1 hour after the ATD dose before starting iodine.PTU is generally preferred over MMI in storm because of its additional peripheral T4→T3 conversion blockade — PTU produced ~45% T3 reduction in the first 24h vs. ~10–15% with MMI in comparative data.

11.2 Supportive Care Bundle

• ICU-level monitoring and respiratory care as needed.
• Cooling measures: acetaminophen (AVOID aspirin/salicylates — they displace T4 from binding globulin and can worsen free hormone levels) + cooling blankets.
• Aggressive volume resuscitation and nutritional support.
• Identify and treat the precipitating illness/event (infection, DKA, surgery, parturition, ATD nonadherence, etc.).
• Consider plasmapheresis/plasma exchange or emergency thyroidectomy in patients failing standard multimodal therapy.

11.3 Prevention

• Patient education to never abruptly stop ATDs without medical guidance.
• Ensure euthyroidism before elective surgery, labor/delivery, or other planned major physiologic stressors.

✦  CLINICAL PEARLS Pearl 7: Remember the drug order as “ATD → wait ≥ 1 hour → iodine”, and the rationale — iodine given first can fuel further hormone synthesis before the gland is pharmacologically blocked.Pearl 8: Hydrocortisone in thyroid storm serves DUAL purpose: adrenal insufficiency prophylaxis (severe thyrotoxicosis accelerates cortisol clearance) AND mild T4→T3 blockade — don’t view it as “just stress-dose steroids.”

Toxic Multinodular Goiter (TMNG) & Toxic Adenoma (TA)

• Two definitive options: RAI therapy or thyroidectomy (Recommendation 37, weak; moderate-quality evidence). Long-term low-dose MMI may be appropriate occasionally (e.g., limited life expectancy, poor surgical/RAI candidacy, patient preference — Recommendation 56).
• ATDs alone do NOT cure TMNG/TA — there is no autoimmune remission mechanism; relapse is expected upon discontinuation, so ATD therapy here is chronic/palliative, not curative.
• Typical maintenance MMI dose in this setting: LOW, usually 5–10 mg/day; monitor more frequently (every 3 months initially) because control can be difficult to titrate long-term.
• RAI: preferred activity/approach parallels GD dosing (see Section 9); ethanol or radiofrequency ablation (RFA) are alternative options in select patients/centers, though evidence base is more limited.
• Persistent/recurrent hyperthyroidism after INADEQUATE surgery → treat with RAI (not repeat surgery, given the higher complication risk of reoperation) (Recommendation 55).

⚠  PHARMACIST WATCHOUT TMNG/TA patients on chronic low-dose MMI: do NOT expect — or attempt to induce — remission with a fixed treatment course the way you would in Graves’ disease. This is fundamentally different pharmacology (autonomous nodule vs. autoimmune antibody-driven disease) and needs indefinite therapy if ATD is the chosen modality.

Subclinical Hyperthyroidism — Management

• If treatment is indicated (see Section 5.3 decision table), treat based on the SAME principles/agents as overt hyperthyroidism, tailored to etiology (Recommendation 77).
• RAI is appropriate for most, especially older patients where TMNG is a common cause.
• ATD course is a reasonable alternative to RAI, especially in younger patients with GD-associated SH (remission rates highest in mild disease).
• Younger GD patients with SH may remit spontaneously — observation with thyroid function testing every 3–6 months is reasonable in select cases.
• Beta-blockade alone may adequately control cardiovascular morbidity (especially AF risk) in some SH patients without need for definitive therapy.
• Goal of therapy: normalize TSH into the age-adjusted reference range; follow hyperthyroid symptoms or bone density as applicable end points.

Hyperthyroidism in Pregnancy & Lactation

14.1 Diagnosis in Pregnancy

• Use trimester-specific reference ranges for free T4/T3, OR total T4/T3 with the nonpregnant reference range multiplied by 1.5 after gestational week 16 (Recommendation 78).
• Distinguish TRANSIENT hCG-mediated gestational (biochemical) hyperthyroidism (common in weeks 9–13, asymptomatic/mild, self-limited, TRAb-negative) from true GD (TRAb-positive, may have goiter/orbitopathy) — gestational hyperthyroidism does NOT require ATD therapy (Recommendation 79).

14.2 ATD Selection by Trimester — ATA Table 11

Scenario	Recommended action
GD diagnosed in 1st trimester	Start PTU. Measure TRAb at diagnosis; if elevated, repeat at 18–22 wks and 30–34 wks.
GD diagnosed after 1st trimester	Start MMI. Same TRAb monitoring schedule.
Already on MMI, pregnancy confirmed	Switch to PTU (or withdraw ATD if appropriate) as soon as pregnancy is confirmed.
In remission, ATD previously stopped	Confirm euthyroidism with TFTs; TRAb measurement not necessary.
Prior RAI or surgery for GD	Measure TRAb in 1st trimester; repeat at 18–22 wks if elevated.

✖  RED FLAG / URGENT MMI use in the first trimester (gestational weeks 6–10, the period of highest teratogenic risk) is associated with a specific embryopathy (choanal/esophageal atresia, aplasia cutis, characteristic facial features) — this is WHY PTU is preferred specifically for the 1st trimester despite its own hepatotoxicity risk. PTU’s rare hepatotoxicity is judged the lesser risk during this specific 6–10-week window.The FDA recommends PTU be reserved for 1st-trimester pregnancy or patients allergic/intolerant to MMI, specifically because of PTU’s hepatotoxicity risk outside that narrow high-risk teratogenic window.

14.3 Dosing Principles in Pregnancy

• Use the LOWEST ATD dose that controls maternal thyroid function — ATDs cross the placenta and can cause FETAL hypothyroidism/goiter if overdosed.
• Target maternal free T4/T3 at or slightly ABOVE the upper limit of the trimester-specific normal range using the lowest possible ATD dose (avoid over-treating the mother into the fetus becoming hypothyroid).
• Beta-blockers: propranolol (10–20mg q8h) or metoprolol (100mg daily) are reasonable short-term options for symptom control; avoid prolonged use (fetal growth restriction reported, especially with atenolol) and avoid atenolol in pregnancy altogether.
• “Block-and-replace” is absolutely avoided in pregnancy — LT4 does not meaningfully cross the placenta, so this strategy exposes the fetus to full ATD dose with no fetal benefit from the maternal LT4.

14.4 TRAb & Fetal/Neonatal Risk

• High maternal TRAb in late pregnancy signals risk of neonatal/fetal hyperthyroidism (antibodies cross the placenta even after maternal thyroid ablation by RAI/surgery) — this is why TRAb is still checked even in “burned-out” post-ablative Graves’ patients who are pregnant.
• If a TRAb-positive woman becomes TRAb-negative during pregnancy, this may signal a need to REDUCE or STOP ATD therapy to avoid fetal hypothyroidism.

14.5 Lactation

• MMI is the PREFERRED ATD during breastfeeding (PTU’s hepatic necrosis risk to mother/child, even if rare, outweighs the mild theoretical benefit).
• Both MMI and PTU appear in breast milk only in small amounts; breastfed infants of ATD-treated mothers show normal thyroid function and neurodevelopment in studies.
• Propranolol/metoprolol: safe in breastfeeding without special infant monitoring (low milk transfer). Atenolol: AVOID (higher milk transfer + immature infant renal clearance → neonatal beta-blockade symptoms).
• RAI is contraindicated during lactation — breastfeeding should be discontinued ≥3 months before ¹³¹I administration and NOT resumed afterward; if diagnostic imaging is needed while nursing, use short-half-life ¹²³I or ⁹⁹ᵐTc instead of ¹³¹I, and pump/discard milk for ~10 half-lives.

14.6 Postpartum Thyroiditis

• A destructive thyroiditis presenting within the first year postpartum; treat thyrotoxic phase supportively with beta-blockers (propranolol/metoprolol) — NOT ATDs (there’s no hormone overproduction to block).
• If TSH >10 mU/L or symptomatic hypothyroid phase develops, LT4 may be used transiently.

✦  CLINICAL PEARLS Pearl 9: “PTU in the 1st trimester, MMI after” is one of the highest-yield board facts in this guideline — and it is a PHARMACIST-DRIVEN counseling point: any reproductive-age woman on MMI must be counseled on contraception/pregnancy-planning BEFORE conception is attempted, since the switch needs to happen as soon as pregnancy is confirmed (ideally before, if planned).

Pediatric Graves’ Disease — Key Differences

• MMI is the ATD of choice in children (Recommendation 59, strong; moderate-quality evidence) — PTU is generally AVOIDED due to higher pediatric hepatotoxicity risk.
• Beta-blockade recommended for symptomatic children, especially HR >100 bpm (Recommendation 62); cardioselective agents (atenolol/metoprolol) preferred if reactive airway disease present, with monitoring for asthma exacerbation.
• Definitive therapy: thyroidectomy preferred in young children too small/unsuitable for RAI, performed by a HIGH-VOLUME pediatric thyroid surgeon; RAI is an option in older children/adolescents.
• Block-and-replace is discouraged in children too (higher adverse event rate in meta-analyses).
• Monitor weight in ATD-treated children — excessive weight gain reported with treatment.

Graves’ Orbitopathy (GO) — Hyperthyroidism Treatment Selection

16.1 Steroid Coverage Decision Matrix (ATA Table 14) — when using RAI

GO status	RAI alone	RAI + oral glucocorticoid
No GO, nonsmoker	Recommended	Recommend AGAINST
No GO, smoker	Insufficient data either way
Mild, active, no risk factors	Acceptable	Acceptable
Mild, active, risk factors present	Recommend AGAINST	Recommended
Moderate–severe or sight-threatening, active	Recommend AGAINST — use ATDs or surgery instead
Inactive GO	Recommended	Recommend AGAINST

• Steroid regimen for GO prophylaxis around RAI: prednisone 0.4–0.5 mg/kg/day, started 1–3 days after RAI, continued 1 month, then tapered over 2 months (a lower-dose ~0.2mg/kg/day x 6 weeks regimen has also shown efficacy in patients with initially mild/absent GO).
• Most task force members use a minimum starting dose of prednisone 30mg/day, tapering over 6–8 weeks in practice.

⚠  PHARMACIST WATCHOUT Risk factors that argue FOR glucocorticoid coverage with RAI: high pretreatment TRAb (>8.8 IU/L), active smoking, active/progressive GO in the preceding 3 months.Risk factors that argue AGAINST glucocorticoids (favor an alternative modality instead): poorly controlled diabetes, uncontrolled hypertension, osteoporosis, active psychiatric illness, high infection risk — these increase complication risk from the steroid itself.

Destructive Thyroiditis (No ATDs Needed)

Key pharmacotherapy principle: these are hormone-RELEASE (not overproduction) states — ATDs are NOT indicated. Management is symptomatic (beta-blockers) ± anti-inflammatory therapy ± transient LT4 during a subsequent hypothyroid phase.

17.1 Subacute (de Quervain’s / Granulomatous) Thyroiditis

• Painful, firm/hard gland; markedly elevated ESR (often >50, sometimes >100mm/h); presumed post-viral.
• First-line: beta-blockers PRN for thyrotoxic symptoms + NSAIDs for pain (Recommendation 117, strong). Median time to pain resolution with NSAIDs: ~5 weeks.
• If failing NSAIDs or presenting with moderate–severe pain/thyrotoxic symptoms initially: corticosteroids — e.g., prednisone 40mg/day x 1–2 weeks, then taper over 2–4+ weeks (mean pain resolution ~8 days vs. 35 days with NSAIDs in one comparison); a lower starting dose (prednisolone 15mg/day, tapering by 5mg every 2 weeks) has also shown efficacy, though ~20% needed >8 weeks to fully taper off.
• LT4 may be used transiently during the hypothyroid phase but should be withdrawn after 3–6 months once recovery of normal function is verified.

17.2 Painless (Silent) / Postpartum Thyroiditis

• Supportive care with beta-blockers (propranolol/metoprolol — NOT atenolol if breastfeeding) during the thyrotoxic phase (Recommendation 97, strong).
• LT4 may benefit symptomatic hypothyroid-phase patients or those with TSH >10 mU/L.
• If GD vs. destructive thyroiditis distinction is unclear postpartum and imaging is needed while nursing, use ¹²³I or ⁹⁹ᵐTc (short half-life) rather than ¹³¹I.

17.3 Acute (Infectious) & Palpation Thyroiditis

• Acute (infectious): rare, typically bacterial; needs antimicrobial therapy ± drainage in addition to supportive thyrotoxicosis management — not primarily an ATD-treated condition.
• Palpation thyroiditis: transient thyrotoxicosis from vigorous gland manipulation (exam or intraoperative) — self-limited, supportive care only.

✦  CLINICAL PEARLS Pearl 10: If a resident orders methimazole for a patient with painful thyroiditis and a sky-high ESR, that’s a catch moment — there is no hormone overproduction to block; the correct answer is NSAIDs/steroids + beta-blocker, not an ATD.

Drug-Induced Thyrotoxicosis

18.1 ATA Table 16 — Causes, Onset, and Therapy

Drug	Mechanism	Onset	Therapy
Amiodarone — type 1	Iodine-induced (excess synthesis substrate)	Months–years	Supportive care; ATDs ± perchlorate; surgery if refractory
Amiodarone — type 2	Destructive thyroiditis	Often >1 year	Supportive care; corticosteroids; surgery if refractory
Lithium	Painless thyroiditis, OR unmasked GD	Often >1 year	Supportive care (thyroiditis); ATDs and/or RAI if GD
Interferon-α	Painless thyroiditis, OR GD	Months	Supportive care; ATDs/RAI if GD
Interleukin-2	Painless thyroiditis, OR GD	Months	Supportive care; ATDs/RAI if GD
Iodinated contrast	Unmasks underlying thyroid autonomy	Weeks–months	Antithyroid drugs
Tyrosine kinase inhibitors	Destructive process	3–12 months	Supportive care
RAI (early phase)	Destructive (radiation thyroiditis)	1–4 weeks	Observation; corticosteroids if severe
RAI in TMNG (late)	Unmasked/persistent GD	3–6 months	ATDs; repeat RAI; surgery

18.2 Amiodarone-Induced Thyrotoxicosis (AIT) — Pharmacist Focus

• Type 1 (iodine-induced, usually pre-existing nodular disease/latent Graves’): treat with ATDs ± perchlorate (not available in the U.S.); surgery if refractory.
• Type 2 (destructive thyroiditis in a normal gland, direct amiodarone toxicity): treat with corticosteroids; ATDs are NOT effective (no overproduction to block).
• Mixed/indeterminate forms are common in practice — color-flow Doppler ultrasound can help distinguish (increased flow = type 1/hyperactive; decreased flow = type 2/destructive) when the picture is unclear.
• Decision to continue or stop amiodarone should be individualized with cardiology — it is not an automatic “stop the drug” situation, especially if amiodarone is essential for life-threatening arrhythmia control and no alternative exists.

⚠  PHARMACIST WATCHOUT Amiodarone’s long half-life (weeks–months) means iodine-related thyroid effects (and impaired T4→T3 conversion) can persist long AFTER the drug is discontinued — don’t expect immediate resolution of thyroid tests after stopping amiodarone.Amiodarone itself elevates total/free T4 and reverse T3 while modestly lowering T3 in EUTHYROID patients (via deiodinase inhibition) — do not mistake this expected pattern for thyrotoxicosis without a correspondingly suppressed TSH.

Other / Unusual Causes of Thyrotoxicosis (ATA Table 17)

Cause	Diagnosis	Primary management
TSH-secreting pituitary adenoma	Pituitary MRI; α-subunit:TSH ratio	Surgical removal
Struma ovarii	RAI uptake over the pelvis	Surgical removal
Choriocarcinoma	Elevated hCG without pregnancy	Surgical removal
Thyrotoxicosis factitia (surreptitious LT4/LT3)	Absent goiter; suppressed thyroglobulin	Psychosocial evaluation ± medication reconciliation intervention
Functional thyroid cancer metastases	Whole-body RAI scan	RAI ablation, embolization, and/or surgery

Overall Diagnostic & Treatment-Selection Algorithm

20.1 Diagnostic Sequence

• 1. Confirm biochemical thyrotoxicosis: TSH + free T4 + total T3.
• 2. History/exam: goiter character, eye signs, tenderness, recent iodine/amiodarone/contrast exposure, supplement use, postpartum status.
• 3. If etiology unclear: check TRAb (fast, cost-effective) OR obtain RAIU/scan (especially if nodular gland suspected) OR Doppler ultrasound (if RAIU contraindicated — pregnancy/lactation).
• 4. Classify: overt vs. subclinical; determine severity (mild/moderate/severe by fT4); screen for thyroid storm features (BWPS) if systemically unwell.
• 5. Select modality: ATD, RAI, or surgery — individualized by etiology, severity, comorbidities, GO status, pregnancy plans, and patient preference (shared decision-making).

20.2 Modality Selection — Quick Reference

Clinical scenario	Preferred approach(es)
Graves’ disease, mild-moderate, no urgent definitive-therapy need	MMI (12–18 month course); RAI or surgery also reasonable per patient preference
Graves’ disease + moderate–severe/active GO	ATDs or surgery; AVOID RAI
Graves’ disease, 1st-trimester pregnancy	PTU
Graves’ disease, pregnancy after 1st trimester	MMI
TMNG / Toxic adenoma, definitive therapy desired	RAI or surgery
TMNG/TA, poor surgical/RAI candidate	Chronic low-dose MMI (5–10mg/d)
Subclinical hyperthyroidism meeting treatment criteria	Same options as overt disease, etiology-based
Destructive thyroiditis (subacute/painless/postpartum)	Beta-blockers ± NSAIDs/steroids; NO ATD
Thyroid storm (BWPS ≥45)	Multimodal: PTU (preferred) + iodine (after ATD) + beta-blocker + hydrocortisone + supportive/ICU care
Amiodarone-induced thyrotoxicosis type 1	ATD ± perchlorate
Amiodarone-induced thyrotoxicosis type 2	Corticosteroids

Selected Clinical Trials & Evidence Base (Brief)

Very brief summaries of key comparative studies underlying major ATA recommendations. Population (P) / Intervention (I) / Comparator (C) / Result (R).

Study / topic	P / I / C / R (brief)
Sundaresh et al. 2013 — network meta-analysis, J Clin Endocrinol Metab	P: Graves’ hyperthyroidism patients across studies; I/C: ATDs vs. RAI vs. surgery; R: comparative effectiveness data underlying the ATA’s equal-acceptability stance on the 3 modalities for uncomplicated GD.
Abraham et al. 2010 — Cochrane review, ATD regimens for GD	P: GD patients; I: various ATD dosing regimens (titration vs. block-replace); C: each other; R: block-and-replace showed HIGHER adverse event rates without efficacy benefit — basis for recommending AGAINST routine block-and-replace.
Nakamura et al. 2007 — MMI vs. PTU comparison, J Clin Endocrinol Metab	P: GD patients; I: MMI; C: PTU; R: MMI showed faster normalization of thyroid function and fewer side effects at equivalent potency ratios — supports MMI as first-line ATD.
Sato et al. 2015 — MMI+iodine vs. high-dose MMI RCT, Thyroid	P: moderate–severe GD; I: MMI 15mg + inorganic iodine 38mg/day; C: MMI 30mg/day alone; R: combination arm had BETTER control with FEWER adverse reactions.
Braga et al. 2002 / Walter et al. 2007 (meta-analysis) — ATD pretreatment before RAI	P: GD patients undergoing RAI; I: MMI pretreatment/discontinuation timing; C: no pretreatment; R: MMI held 2–3 days pre-RAI avoids blunting uptake; resuming 3–7 days post-RAI reduces post-RAI hormone surge in high-risk patients.
Traisk et al. 2009 (“TT96”) — GO outcomes by GD therapy, J Clin Endocrinol Metab	P: GD patients (some with mild pre-existing GO); I: RAI; C: ATDs / surgery; R: RAI associated with HIGHER risk of new/worsening GO (RR up to ~5.8) vs. ATDs; risk mitigated by concurrent glucocorticoids — basis for steroid-coverage recommendations.
Franklyn et al. 1998 / Boelaert et al. 2013 — mortality after RAI	P: hyperthyroid patients treated with RAI; I: RAI resulting in hypothyroidism vs. persistent hyperthyroidism; R: persistent post-RAI hyperthyroidism (inadequate dosing) associated with increased cardiovascular/cerebrovascular mortality — supports using sufficiently high, ablative RAI activities rather than low “euthyroid-targeting” doses.
de Rooij et al. 2009 — meta-analysis, fixed vs. calculated RAI activity	P: GD patients receiving RAI; I: calculated (uptake/gland-size-based) dosing; C: fixed-activity dosing; R: no clear outcome advantage for calculated dosing — supports simpler fixed-dose approach in most practice settings.

These are intentionally brief per your preference — pull full trial methodology/results from the primary literature or UpToDate/Lexicomp when needed for a specific case or board question.

Master List — Pharmacist Watchouts

22.1 On Multidisciplinary Rounds

• Confirm etiology matches therapy: ATD ordered? Confirm this is a hormone-overproduction state (GD/TMNG/TA), not thyroiditis.
• Flag “block-and-replace” orders (ATD + LT4 together) as generally non-recommended — raise with the team.
• For pregnant patients: confirm PTU is being used in the 1st trimester and MMI after — flag any mismatch immediately.
• For thyroid storm orders: confirm sequencing — ATD dose given, THEN iodine ≥ 1 hour later. Confirm PTU (not MMI) is being used if peripheral conversion blockade is desired.
• Confirm pregnancy test was done and documented negative within 48h before any RAI order in a woman of childbearing potential.
• For pre-thyroidectomy patients: confirm SSKI/Lugol’s solution has been started ~10 days pre-op (if GD) and that the patient has been rendered euthyroid with MMI beforehand when feasible.
• Post-thyroidectomy: proactively check for symptoms/labs of hypocalcemia and voice change; confirm a calcium/calcitriol supplementation plan exists.
• For amiodarone patients with new thyrotoxicosis: don’t default to “start methimazole” — confirm type 1 vs. type 2 (or mixed) has been considered, since therapy differs completely.

22.2 On Boards / Exams

• MMI = once daily, first-line, teratogenic in 1st trimester (embryopathy). PTU = divided dosing, preferred in 1st trimester + thyroid storm, hepatotoxicity boxed warning.
• Beta-blockers are appropriate in essentially ALL causes of thyrotoxicosis (symptom control); ATDs are appropriate ONLY in true hormone-overproduction states.
• BWPS ≥45 = thyroid storm; 25–44 = impending (clinical judgment); <25 = unlikely.
• TSH <0.1 mU/L + age ≥65 (or cardiac disease/osteoporosis/symptoms) = treat subclinical hyperthyroidism.
• TRAb positive → confirms Graves’; TRAb negative does NOT exclude mild Graves’.
• T3:T4 ratio >20 = true hyperthyroidism; <20 = thyroiditis/factitious.
• Radioactive iodine = absolute contraindication in pregnancy and lactation; contraindicated in moderate-severe active GO.
• Agranulocytosis and hepatotoxicity both cluster within the first 90–120 days of ATD therapy — symptom-triggered (not routine) monitoring is the guideline stance.

22.3 During Medication Reconciliation / Med Review

• Screen for iodine-containing supplements, seaweed, kelp, and “thyroid support” products — can precipitate iodine-induced hyperthyroidism in susceptible patients (autonomous nodules) or confound RAIU-based diagnosis/therapy.
• Screen for amiodarone (current or recent, given its long half-life) whenever new thyroid dysfunction appears.
• Screen for lithium, interferon-α, interleukin-2, and tyrosine kinase inhibitors as potential precipitants of drug-induced thyroid dysfunction.
• Screen for biotin/high-dose B-vitamin supplements before trusting an unexpected TSH/fT4 result that doesn’t fit the clinical picture.
• In any reproductive-age woman on MMI, confirm contraception status/pregnancy plans are being addressed — this drives the MMI→PTU switch timing.
• Verify no recent iodinated contrast study or amiodarone exposure before a planned RAI treatment (can blunt uptake / cause treatment failure).

22.4 Patient Counselling Points

• Give WRITTEN information on ATD warning symptoms at initiation and every visit: sore throat/fever/mouth sores — STOP drug, get CBC now; jaundice/dark urine/pale stools/abdominal pain/nausea — STOP drug, get LFTs now.
• Never abruptly stop an ATD without medical guidance — abrupt discontinuation is a recognised precipitant of thyroid storm.
• Counsel on radiation safety precautions after RAI (per institutional/physician instructions) — pregnancy avoidance timing (women ≥4–6 months, men ≥3–4 months), and no breastfeeding resumption after RAI.
• Counsel Graves’ patients on smoking cessation specifically to reduce orbitopathy risk/progression — mention this is the single most modifiable GO risk factor.
• Counsel that a single “normal” thyroid panel doesn’t guarantee stability — two normal panels ≥1 month apart, without a dose change, are needed to call the patient truly euthyroid.
• For pregnant/planning patients on MMI: counsel about the importance of confirming pregnancy early and contacting the provider promptly so the ATD can be switched/adjusted as soon as possible.

Consolidated Clinical Pearls

A single running list of every pearl in this guide, for quick self-quizzing.

• “Hyperthyroidism” ≠ “thyrotoxicosis.” Get etiology right before choosing a drug class.
• New AF in a patient >60 → check TSH; SH with TSH <0.1 is itself a treatment indication in this age group.
• Smoking cessation belongs in every Graves’ medication review — biggest modifiable GO risk factor.
• Two normal thyroid panels ≥1 month apart, no dose change in between, needed to call a patient euthyroid.
• MMI 15mg + KI 38mg outperformed MMI 30mg alone in an RCT (better control, fewer ADRs) — useful adjunct concept.
• 2nd trimester is the safest window for thyroidectomy in pregnancy, if surgery is truly required.
• Thyroid storm drug order: ATD first, wait ≥1 hour, THEN iodine. PTU preferred over MMI for its added T4→T3 blockade.
• Hydrocortisone in thyroid storm = adrenal insufficiency prophylaxis + mild T4→T3 blockade, not just “stress dose.”
• PTU in 1st trimester, MMI thereafter — counsel reproductive-age women on MMI about this switch BEFORE conception.
• Painful goiter + very high ESR + no TRAb = subacute thyroiditis — NSAIDs/steroids + beta-blocker, NOT an ATD.