Thyrogen Side Effects, and Drug Interactions - Thyrotropin Alfa

Thyrogen Side Effects, and Drug Interactions - Thyrotropin Alfa

SIDE EFFECTS

Adverse reaction data are derived from the two clinical trials in which 381 patients were treated with Thyrogen (thyrotropin alfa for injection) and from post-marketing surveillance.

The most common adverse events (> 5%) reported in clinical trials were: nausea (10.5%) and headache (7.3%). Events reported in ≥ 1% of patients in the trials are summarized in the following table:

There have been several reports of hypersensitivity reactions including urticaria, rash, pruritus and flushing. However, in clinical trials no patients have developed antibodies to thyrotropin alfa, either after single or repeated (27 patients) use of the product.

Four patients out of 55 (7.3%) with CNS metastases who were followed in a special treatment protocol experienced acute hemiplegia, hemiparesis or pain one to three days after Thyrogen administration. The symptoms were attributed to local edema and/or focal hemorrhage at the site of the cerebral or spinal cord metastases. In addition, one case each of acute visual loss and of dysphagia secondary to laryngeal edema, requiring tracheotomy, have been reported 24 hours after Thyrogen administration in patients with metastases to the optic nerve and paratracheal areas, respectively. Pre-treatment with corticosteroids may be considered under such circumtances.

A 77 year-old non-thyroidectomized patient with a history of heart disease and spinal metastases who received 4 Thyrogen injections over 6 days in a special treatment protocol experienced a fatal MI 24 hours after he received the last Thyrogen injection. The event was likely related to Thyrogen-induced hyperthyroidism.

Formal interaction studies between Thyrogen and other medicinal products have not been performed. In clinical trials, no interactions were observed between Thyrogen and the thyroid hormones triiodothyronine (T ₃ ) and thyroxine (T ₄ ) when administered concurrently.

The use of Thyrogen allows for radioiodine imaging while patients are euthyroid on triiodothyronine (T ₃ ) and/or thyroxine (T ₄ ). Data on radioiodine ¹³¹ l kinetics indicate that the clearance of radioiodine is approximately 50% greater in euthyroid patients than in hypothyroid patients, who have decreased renal function. Thus radioiodine retention is less in euthyroid patients at the time of imaging and this factor should be considered when selecting the activity of radioiodine for use in radioiodine imaging.