Drug reference

thyrotropin alpha

Recombinant human thyroid-stimulating hormone (diagnostic/adjunct) · diagnostic agent, adjunct to radioiodine therapy

START

0.9 mg IM into buttock on two consecutive days

TYPICAL MAX

0.9 mg IM on each of two consecutive days per cycle

STOP IF

Severe hypersensitivity or symptomatic tumour swelling

WATCH

Local/compressive symptoms (CNS/airway mets), cardiac symptoms

CDSCO approvedATC H01AB01

Renal dose adjustmenteGFR mL/min/1.73m²

KDIGO 2024 + manufacturer label

Pharmacokineticsplasma · t hours

ONSET: 4h · absorption
PEAK: 10h · serum TSH peak
t½: 1.2d · t½
DURATION: 4d · test window

EXCRETION

Proteolytic catabolism; renal clearance

route + CYP

INTERACTIONS

—

none in our sources

PREGNANCY

Limited data; use only if clearly needed (diagnostic).

FDA category + note

Mechanism

Recombinant human TSH (thyrotropin alfa) binds thyroid TSH receptors, stimulating iodine uptake and thyroglobulin synthesis/release — enabling thyroid-cancer follow-up testing/remnant ablation without thyroid-hormone withdrawal.

Indications

Adjunct for serum thyroglobulin testing in differentiated thyroid cancer follow-upAdjunct for radioiodine remnant ablation after thyroidectomyAdjunct to radioiodine imaging

Dosing

Adult: 0.9 mg IM into the buttock on two consecutive days; radioiodine or thyroglobulin sampling per protocol after the second dose.
Pediatric: Limited data; specialist.
Renal adjustment: Renally cleared — clearance reduced in dialysis (prolonged effect); no fixed dose change.
Hepatic adjustment: No specific adjustment.
Geriatric: Standard regimen; cardiac caution.
Max dose: 0.9 mg IM on each of two consecutive days (per cycle)

Pharmacokinetics

Onset

TSH effect within hours of IM dose

Peak effect

~3–24 h (serum TSH peak)

Duration

Effect over several days (testing window)

Half-life

~22–35 h

Bioavailability

IM absorbed (recombinant glycoprotein)

Protein binding

Not applicable (glycoprotein hormone)

Metabolism

Proteolytic catabolism

Excretion

Catabolised; renal clearance contribution

Contraindications

Hypersensitivity to bovine or human TSH / thyrotropin alfa
Caution: residual thyroid cancer with possible compressive expansion

Side effects

Common

NauseaHeadacheFatigueAstheniaDizziness

Serious

Tumour/thyroid-remnant swelling (local compression — airway/CNS metastases)
Transient hyperthyroid symptoms / arrhythmia
Severe hypersensitivity
Stroke (rare, reported)

Pregnancy & lactation

Pregnancy

Limited data; use only if clearly needed (diagnostic).

Lactation

Limited data; brief diagnostic use — weigh benefit/risk.

Drug interactions

Amiodarone

Moderate

Database

Iodine competition reduces radioiodine uptake

Account for iodine load; timing per protocol