nafarelin acetate
Pharmacologic class: Gonadotropin-releasing hormone (GnRH)
Therapeutic class: Hormone
Pregnancy risk category X
Action
Inhibits secretion of gonadotropin, a luteinizing hormone (LH)-releasing hormone. Initially increases pituitary production of LH and follicle-stimulating hormone (FSH), which ultimately leads to deactivation of testicular and ovarian functions.
Availability
Nasal spray: 2 mg/ml in 10-ml bottle (200 mcg/spray)
Indications and dosages
➣ Endometriosis
Adults: One spray (200 mcg) intra-nasally in one nostril in morning and one spray in other nostril in evening (400 mcg/day). May increase to one spray in each nostril in morning and evening (800 mcg/day).
➣ Central precocious puberty
Children: Two sprays in each nostril in morning and evening (1,600 mcg/day). May increase up to 1,800 mcg/day (three sprays in alternating nostrils t.i.d.).
Contraindications
• Hypersensitivity to GnRH, its analogs, or sorbitol
• Undiagnosed abnormal vaginal bleeding
• Pregnancy or breastfeeding
Precautions
Use cautiously in:
• rhinitis, ovarian cysts, major risk factors for bone density loss (such as chronic alcoholism or chronic corticosteroid use).
Administration
• Make sure patient isn't pregnant before starting therapy.
• For endometriosis, start therapy on day 2 to day 4 of menstrual period.
• If patient needs topical decongestant, wait at least 2 hours after nafarelin dose before giving.
• Know that retreatment for endometriosis isn't recommended.
Adverse reactions
CNS: emotional lability, headache, depression, insomnia, seizures
CV: chest pain, thromboembolism
EENT: nasal irritation, rhinitis
GU: vaginal dryness, bleeding, or discharge; menses cessation; transient breast enlargement; decreased libido
Musculoskeletal: reduced bone density, myalgia
Respiratory: dyspnea
Skin: urticaria, rash, pruritus, acne, oily skin, hirsutism, transient pubic hair increase
Other: weight changes, hot flashes, edema, body odor, hypersensitivity reaction
Interactions
Drug-drug. Topical nasal decongestants: reduced nafarelin absorption
Patient monitoring
• Monitor patient for emotional lability or depression.
• Assess nasal mucosa for erosion.
• Monitor vital signs. Weigh patient regularly; report edema.
• Stay alert for adverse hormonal effects, including hot flashes, menses cessation followed by breakthrough bleeding, hirsutism, acne, decreased libido, and vaginal dryness.
Closely monitor patient for signs and symptoms of seizures and thromboembolism.
Patient teaching
• Instruct patient to complete entire course of therapy. Advise her to keep enough of drug on hand to prevent interruption.
• Inform patient that regular menstruation should cease after 4 to 6 weeks of therapy but that breakthrough bleeding may still occur.
• Tell patient ovulation may still occur. Instruct her to use barrier contraception during therapy and to report suspected pregnancy.
• Caution patient not to breastfeed.
• Teach patient about adverse hormonal effects. Identify which signs and symptoms to report.
• Inform patient that drug may cause emotional changes or depression. Advise her to report these to prescriber.
Instruct patient to immediately report signs and symptoms of seizures and thromboembolism.
• As appropriate, review all other significant adverse reactions and interactions, especially those related to the drugs mentioned above.