Nafarelin

Summary

Nafarelin is a potent synthetic GnRH agonist administered intranasally. It is approved for the treatment of endometriosis and central precocious puberty. Chronic administration creates a hypogonadal state by desensitizing pituitary GnRH receptors, effectively suppressing sex hormone production.

Mechanism of Action

Synthetic analog of gonadotropin-releasing hormone (GnRH) that, upon continuous administration, downregulates pituitary GnRH receptors, leading to suppression of LH and FSH secretion, and consequently reduced production of gonadal steroids (estradiol and testosterone).

Routes of Administration

Goals & Uses

• Treatment of endometriosisGynecologyHigh
• Treatment of central precocious pubertyPediatric EndocrinologyHigh
• Uterine fibroids (leiomyomata) managementGynecologyModerate
• Ovarian stimulation suppression in assisted reproductionReproductive MedicineModerate

Contraindications

• PregnancyPopulationHighPotential fetal risk or insufficient safety data
• BreastfeedingPopulationHighPotential transfer into breast milk or insufficient safety data
• Undiagnosed abnormal vaginal bleedingGynecologyHigh
• Hypersensitivity to GnRH or GnRH analogsAllergy / ImmunologyHigh
• Osteoporosis or significant bone lossMusculoskeletalModerate

Adverse Effects

• Nasal irritation / rhinitisLocal/NasalCommon
• HeadacheNeurologicCommonPain in the head or upper neck
• Decreased bone mineral densityMusculoskeletalCommon
• Hot flashesEndocrine / VasomotorCommon
• Mood changes / depressionPsychiatricUncommon
• Vaginal drynessGynecologicCommon

Drug Interactions

• Nasal decongestants (topical)Moderate
• Sex hormone preparations (estrogens, androgens, progestogens)Moderate

Population Constraints

• Patients with history of osteoporosisMusculoskeletalRelative
• Patients with chronic nasal conditionsENTRelative
• Pediatric patients under 2 yearsAgeAbsolute
• Adolescents with central precocious pubertyPediatricRelative

Regulatory Status

• European UnionApprovedApproved: Endometriosis, Central precocious pubertyApproved in multiple EU member states; availability may vary by country.
• United StatesApprovedApproved: Endometriosis (management of pain and reduction of lesions), Central precocious puberty (gonadotropin-dependent)FDA-approved; marketed as Synarel nasal spray (200 mcg/spray). Original approval 1990.
• United KingdomApprovedApproved: Endometriosis, Central precocious pubertyApproved by MHRA; marketed as Synarel in the UK.

Approved by the FDA in 1990 for endometriosis and central precocious puberty. Marketed as Synarel nasal spray. Approved in the EU and other jurisdictions for similar indications.

Evidence & Sources

No sources recorded yet.