thyrotropin alfa: clinical use

Prescribing considerations

• Specialist supervision by clinicians experienced in thyroid cancer is required.
• Assess significant renal impairment carefully; elimination is slower in dialysis-dependent end-stage renal disease and radioiodine selection requires nuclear medicine input.
• In high-risk older patients with cardiac disease and substantial remaining thyroid tissue, assess the risk of transient thyroid hormone elevation.
• Consider whether corticosteroid pre-treatment is appropriate when expansion of metastases could compromise the brain, spinal cord, orbit, airway or other vital structures.
• Use in children should be exceptional because clinical data are limited.
• Record the product name and batch number for biological-medicine traceability.

Contraindications and cautions

• Pregnancy.
• Hypersensitivity to human or bovine TSH or any formulation excipient.
• Intravenous administration is contraindicated by the authorised method of administration.

Monitoring

• Coordinate thyroglobulin testing and imaging with the specialist protocol.
• Measure thyroglobulin antibodies alongside thyroglobulin because antibodies may produce misleadingly low results.
• Recognise that false-negative testing can occur; investigate persistent clinical suspicion appropriately.
• Monitor for headache and nausea in severe renal impairment and acute local symptoms in people with metastases in confined anatomical sites.
• Observe for hypersensitivity, neurological deterioration, respiratory compromise and clinically important arrhythmia.

Clinical pharmacology

Thyrotropin alfa is recombinant human TSH. It activates TSH receptors on thyroid epithelial cells, increasing iodine uptake and stimulating synthesis and release of thyroglobulin and thyroid hormones. Elimination is principally renal, with a smaller hepatic contribution.

Formulation and product differences

• Supplied as a white to off-white lyophilised powder requiring aseptic reconstitution with water for injection.
• The reconstituted solution is for intramuscular injection into the buttock only and must not be mixed with other medicines.
• Each vial is single-use and contains no preservative; the prepared solution should be clear and colourless.

Injection

Route: Parenteral

Strengths: 0.9 mg