Nafarelin acetate
Nafarelin acetate (Synarel)
Nafarelin acetate
( NAF-ah-rel-in)
Pregnancy Category: X Synarel (Rx)

Classification: Gonadotropin-releasing hormone

Action/Kinetics: Produced through biotechnology; differs by only one amino acid from naturally occurring GnRH. Stimulates the release of LH and FSH from the adenohypophysis. Causes estrogen and progesterone synthesis in the ovary, resulting in the maturation and subsequent release of an ovum. With repeated use of the drug, however, the pituitary becomes desensitized and no longer produces endogenous LH and FSH; thus endogenous estrogen is not produced, leading to a regression of endometrial tissue, cessation of menstruation, and a menopausal-like state. Broken down by the enzyme peptidase. Peak serum levels: 10-40 min. t 1/2: 3 hr; 80% is bound to plasma proteins.

Uses: Endometriosis (including reduction of endometriotic lesions) in clients aged 18 or older (400 mcg/day is clinically comparable to 3.75 mg/month of Lupon Depot). Central precocious puberty in children of both sexes.

Contraindications: Hypersensitivity to GnRH or analogs. Abnormal vaginal bleeding of unknown origin. Pregnancy or possibility of becoming pregnant. Lactation.

Special Concerns: Rule out pregnancy before initiating therapy. Safety and effectiveness have not been established in children.

Side Effects: Due to hypoestrogenic effects: Hot flashes (common), decreased libido, vaginal dryness, headaches, emotional lability, insomnia. Due to androgenic effects: Acne, myalgia, reduced breast size, edema, seborrhea, weight gain, increased libido, hirsutism. Musculoskeletal: Decrease in vertebral trabecular bone density and total vertebral bone mass. Miscellaneous: Nasal irritation, depression, weight loss.

Laboratory Test Alterations: Cholesterol and triglyceride levels, plasma phosphorus, eosinophils. Serum calcium, WBCs.

How Supplied: Spray: 0.2 mg/inh

Dosage
?Nasal Spray Endometriosis.
200 mcg into one nostril in the morning and 200 mcg into the other nostril at night (400 mcg b.i.d. may be required by some women).
Central precocious puberty.
400 mcg (2 sprays) into each nostril in the morning (i.e., 4 sprays) and in the evening (total of 8 sprays/day). If adequate suppression is not achieved, 3 sprays (600 mcg) into alternating nostrils t.i.d. (i.e., a total of 9 sprays/day).