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NAFARELIN ACETATE

Medical Diagnosis and Drugs, Medications
NAFARELIN ACETATE
(na-fa're-lin)
Synarel
Classifications: hormone; gonadotropin-releasing hormone analog;
Therapeutic: gonadotropin-releasing hormone analog
Prototype: Leuprolide
Pregnancy Category: X

Availability

0.2 mg/spray solution

Action

Potent agonist analog of gonadotropin-releasing hormone (GnRH). Inhibits pituitary gonadotropin secretion of LH and FSH.

Therapeutic Effect

Decrease in serum estradiol or testosterone concentrations results in the quiescence of tissues and functions that depend on LH and FSH.

Uses

Endometriosis and precocious puberty.

Unlabeled Uses

Uterine leiomyomas, benign prostatic hypertrophy.

Contraindications

Hypersensitivity to GnRH or GnRH agonist analog; undiagnosed abnormal vaginal bleeding; pregnancy (category X), lactation.

Cautious Use

Polycystic ovarian disease; osteoporosis.

Route & Dosage

Endometriosis
Adult: Inhalation 2 inhalations/d (200 mcg/inhalation), one in each nostril, begin between days 2 and 4 of menstrual cycle; in patients with persistent regular menstruation after 2 mo of therapy, may increase to 800 mcg/d as 2 inhalations (one in each nostril) b.i.d.; do not exceed 6 mo of treatment

Precocious Puberty
Child: Inhalation 800–1200 mcg/d divided q8–12h

Administration

Inhalation
  • Withhold any topical nasal decongestant, if being used, until at least 30 min after nafarelin administration.
  • Store at 15°–30° C (59°–86° F); protect from light.

Adverse Effects (≥1%)

GI: Bloating, abdominal cramps, weight gain, nausea. Endocrine: Hot flashes, anovulation, amenorrhea, vaginal dryness, galactorrhea. Metabolic: Decreased bone mineral content (reversible). CNS: Transient headache, inertia, mild depression, moodiness, fatigue. Respiratory: Nasal irritation. Urogenital: Impotence, decreased libido, dyspareunia.

Diagnostic Test Interference

Increased alkaline phosphatase; marked increase in estradiol in first 2 wk, then decrease to below baseline; decreased FSH and LH levels; decreased testosterone levels.

Interactions

Drug: No clinically significant interactions established.

Pharmacokinetics

Absorption: 21% absorbed from nasal mucosa. Onset: 4 wk. Peak: 12 wk. Duration: 30–50 d after discontinuing drug. Distribution: 78–84% bound to plasma proteins; crosses placenta. Metabolism: Hydrolyzed in kidney. Elimination: 44–55% in urine over 7 d, 19–44% in feces. Half-Life: 2.7 h.

Nursing Implications

Assessment & Drug Effects

  • Make appropriate inquiries about breakthrough bleeding, which may indicate that patient has missed successive drug doses.

Patient & Family Education

  • Read the information pamphlet provided with nafarelin.
  • Inform physician if breakthrough bleeding occurs or menstruation persists.
  • Use or add barrier contraceptive during treatment.

Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; Canadian drug name; Prototype drug

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