nafarelin acetate

nafarelin acetate Warning - Hazardous drug!

Synarel

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) intranasally 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.

Route	Onset	Peak	Duration
Intranasal	Within 4 wk	3-4 wk	3-6 mo

Adverse reactions

CNS: emotional lability, headache, depression, insomnia

CV: chest pain

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.

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.
• As appropriate, review all other significant adverse reactions and interactions, especially those related to the drugs mentioned above.