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Synarel (Nafarelin Acetate)
Gonadotropin-releasing hormone agonist medication
Nafarelin acetate (SYNAREL) is a GnRH agonist peptide indicated for central precocious puberty in children and endometriosis in women 18 years and older. The drug is degraded by peptidase rather than cytochrome P-450 enzymes, making pharmacokinetic drug interactions unlikely. Key risks include pituitary apoplexy (rare but serious), psychiatric adverse events including depression and suicidal ideation, and transient stimulatory effects on the pituitary-gonadal axis during initial treatment. Long-term safety requires regular pituitary imaging and careful patient monitoring, particularly for psychiatric symptoms.
At a glance
| Generic name | Nafarelin Acetate |
|---|---|
| Sponsor | Pfizer Inc. |
| Drug class | Gonadotropin-releasing hormone agonists |
| Target | Gonadotropin-releasing hormone receptors |
| Modality | Recombinant protein |
| Therapeutic area | Oncology |
| Phase | FDA-approved |
Mechanism of action
Synarel works by mimicking the action of gonadotropin-releasing hormone (GnRH) in the body. This leads to a decrease in the production of sex hormones, such as estrogen and testosterone. By reducing the levels of these hormones, Synarel helps to treat conditions like endometriosis, uterine fibroids, and central precocious puberty.
Approved indications
- Treatment of central precocious puberty (CPP) (gonadotropin-dependent precocious puberty) in children of both sexes
- Exclusion of other causes of sexual precocity, such as congenital adrenal hyperplasia, testotoxicosis, testicular tumors and/or other autonomous feminizing or masculinizing disorders
- Detection of hypothalamic or pituitary tumors, or anatomical changes associated with increased intracranial pressure
Common side effects
- Acne
- Transient breast enlargement
- Vaginal bleeding
- Emotional lability
- Transient increase in pubic hair
- Rhinitis
- Body odor
- Seborrhea
- Hot flashes
- White or brownish vaginal discharge
- Drug sensitivity symptoms (shortness of breath, chest pain, urticaria, rash, pruritus)
Serious adverse events
- Pituitary apoplexy
- Depression with suicidal ideation and attempt
- Convulsion
- Pseudotumor cerebri (idiopathic intracranial hypertension)
- Pituitary microadenoma
- Pituitary gland enlargement and asymmetry
- Adrenal rest tumors
Drug interactions
- Warfarin
- Hormonal contraceptives
- Insulin
- Oral anticoagulants
- Thyroid medications
- Corticosteroids
- Estrogens
- Progestins
- Rifampin
- Phenytoin
- Barbiturates
- CYP3A4 inducers