Thyrotropin alfa

How it works

It is recombinant human TSH that binds TSH receptors on thyroid follicular (and thyroid cancer) cells, stimulating iodine uptake and thyroglobulin production, thereby enhancing the sensitivity of thyroglobulin measurement and radioiodine studies.

Prescribing in practice

• In patients with residual thyroid tissue or metastases, TSH stimulation can cause local tumour swelling, which may be hazardous where expansion could compress nearby structures, so this risk should be considered and pretreatment with corticosteroids contemplated.
• It is used together with thyroglobulin measurement and, where indicated, radioiodine, and results should be interpreted by clinicians experienced in thyroid cancer follow-up.
• It is given by intramuscular injection and is not a substitute for thyroid hormone replacement therapy.

Monitoring

Monitor stimulated serum thyroglobulin (with antibody status), together with any imaging results, and observe for symptoms of tumour swelling after administration.

Counselling the patient

• This medicine is given as injections, usually as part of scheduled thyroid cancer follow-up.
• It means you can usually stay on your thyroid hormone tablets rather than stopping them.
• Report any neck swelling, pain, or breathing difficulty after the injections.

Evidence & guidelines

Its use in thyroglobulin-stimulated testing and radioiodine remnant ablation is supported by clinical trials in differentiated thyroid cancer follow-up.