ation (see section 4.4).
Renal/hepatic impairment
Information from post marketing surveillance, as well as published information, suggests that elimination of Thyrogen is significantly slower in dialysis-dependent end stage renal disease (ESRD) patients, resulting in prolonged elevation of TSH levels for several days after treatment. This may lead to increased risk of headache and nausea. There are no studies of alternative dose schedules of Thyrogen in patients with ESRD to guide dose reduction in this population.
In patients with significant renal impairment the activity of radioiodine should be carefully selected by the nuclear medicine physician.
The use of Thyrogen in patients with reduced liver function does not warrant special considerations.
Method of administration
After reconstitution with water for injection, 1.0 ml solution (0.9 mg thyrotropin alfa) is administered by intramuscular injection to the buttock. See section 6.6 for instructions for handling.
For radioiodine imaging or ablation, radioiodine administration should be given 24 hours following the final Thyrogen injection. Diagnostic scintigraphy should be performed 48 to 72 hours following radioiodine administration, whereas post-ablation scintigraphy may be delayed additional days to allow background activity to decline.
For diagnostic follow-up serum thyroglobulin (Tg) testing, the serum sample should be obtained 72 hours after the final injection of Thyrogen. Use of Thyrogen with Tg testing in follow up of post-thyroidectomy well differentiated thyroid cancer patients should be in accordance with official guidelines.
4.3 Contraindications
? Hypersensitivity to bovine or human thyroid stimulating hormone or to any of the excipients listed in section 6.1.
? Pregnancy (see section 4.6).
4.4 Special warnings and precautions for use
Thyrogen should not be administered intravenously.
When used as an alternative to thyroid hormone withdrawal, the combination of the whole body scintigraphy (WBS) and Tg testing after Thyrogen administration assures the highest sensitivity for detection of thyroid remnants or cancer. False negative results may occur with Thyrogen. If a high index of suspicion for metastatic disease persists, a confirmatory withdrawal WBS and Tg testing should be considered.
The presence of Tg autoantibodies can be expected in 18-40% of patients with differentiated thyroid cancer and may cause false negative serum Tg measurements. Therefore, both TgAb and Tg assays are needed.
Careful eva luation of benefit-risk relationships should be assessed for Thyrogen administration in high risk elderly patients who have heart disease (e.g. valvular heart disease, cardiomyopathy, coronary artery disease, and prior or current tachyarrhythmia including atrial fibrillation) and have not undergone thyroidectomy.
Thyrogen is known to cause a transient but significant rise in serum thyroid hormone concentration when given to patients who have substantial thyroid tissue still in situ. Therefore, careful eva luation of individual risk-benefit is necessary for patients with significant residual thyroid tissue.
Long term data in relation to use of the lower dose of radioiodine are not yet available.
Effect on tumour growth and/or size:
In patients with thyroid cancer, several cases of stimulated tumour growth have been reported during withdrawal of thyroid hormones for diagnostic procedures which have bee |
