Products
Nafarelin is commercially available as a nasal spray (Synrelina). It has been approved in many countries since 1992.
Structure and properties
Nafarelin (C66H83N17O13, Mr = 1322.5 g/mol) is an agonist derivative and analog of gonadotropin-releasing hormone (GnRH). It is present in the drug as nafarelin acetate. It is a decapeptide that is administered nasally and thus rapidly enters the bloodstream.
- Nafarelin: 5-oxo-Pro-His-Trp-Ser-Tyr-3-(2-naphthyl)-D-Ala-Leu-Arg-Pro-Gly
- GnRH: Pyr-His-Trp-Ser-Tyr-Gly-Leu-Arg-Pro-Gly
Effects
Nafarelin (ATC H01CA02) leads to reduced secretion of the gonadotropins LH and FSH from the pituitary gland (down-regulation) with long-term treatment of about four weeks. As a result, steroid formation in the gonads is reduced and menstruation ceases. Estrogen concentration decreases and the relative proportion of androgens is increased.
Indications
For the treatment of endometriosis and associated pain and tissue lesions.
Dosage
According to the SmPC. One spray is given in one nostril in the morning and one spray in the other nostril in the evening. Treatment should be started between the 2nd and 4th day of the menstrual cycle.
Contraindications
- Hypersensitivity
- Vaginal bleeding that has not been clarified
- Adolescents under 18 years
- Pregnancy and lactation
Full precautions can be found in the drug label.
Interactions
Decongestant nasal sprays may delay onset of action.
Adverse effects
The most common possible adverse effects include a decrease in libido, emotional lability, acne, seborrhea, vaginal dryness, breast involution, weight gain, flushing, headache, muscle pain, nasal mucosa irritation, and edema.
