Synarel Side Effects, and Drug Interactions - Nafarelin

Synarel Side Effects, and Drug Interactions - Nafarelin

SIDE EFFECTS

In clinical trials of 155 pediatric patients, 2.6% reported symptoms suggestive of drug sensitivity, such as shortness of breath, chest pain, urticaria, rash, and pruritus.

In these 155 patients treated for an average of 41 months and as long as 80 months (6.7 years), adverse events most frequently reported (>3% of patients) consisted largely of episodes occurring during the first 6 weeks of treatment as a result of the transient stimulatory action of nafarelin upon the pituitary-gonadal axis:

acne (10%)

transient breast enlargement (8%)

vaginal bleeding (8%)

emotional lability (6%)

transient increase in pubic hair (5%)

body odor (4%)

seborrhea (3%)

Hot flashes, common in adult women treated for endometriosis, occurred in only 3% of treated children and were transient. Other adverse events thought to be drug-related, and occurring in >3% of patients were rhinitis (5%) and white or brownish vaginal discharge (3%). Approximately 3% of patients withdrew from clinical trials due to adverse events.

In one male patient with concomitant congenital adrenal hyperplasia, and who had discontinued treatment 8 months previously to resume puberty, adrenal rest tumors were found in the left testis. Relationship to SYNAREL is unlikely.

Regular examinations of the pituitary gland by magnetic resonance imaging (MRI) or computer assisted tomography of children during long-term nafarelin therapy as well as during the post-treatment period have occasionally revealed changes in the shape and size of the pituitary gland. These changes include asymmetry and enlargement of the pituitary gland, and a pituitary micro-adenoma has been suspected in a few children. The relationship of these findings to SYNAREL is not known.

No pharmacokinetic-based drug-drug interaction studies have been conducted with SYNAREL. However, because nafarelin acetate is a peptide that is primarily degraded by peptidase and not by cytochrome P-450 enzymes, and the drug is only about 80% bound to plasma proteins at 4°C, drug interactions would not be expected to occur.