Classification:
Synthetic androgen (gonadotropin inhibitor)
Action/Kinetics:
Inhibits the release of gonadotropins (FSH and LH) by the anterior pituitary; thus, inhibits synthesis of sex steroids and competitively inhibits binding of steroids to their cytoplasmic receptors in target tissues. In women this action arrests ovarian function, induces amenorrhea, and causes atrophy of normal and ectopic endometrial tissue. Has weak androgenic effects. Onset, fibrocystic disease: 4 weeks. Time to peak effect, amenorrhea and anovulation: 6-8 weeks; fibrocystic disease: 2-3 months to eliminate breast pain and tenderness and 4-6 months for elimination of nodules. t 1/2: 4.5 hr. Duration: Ovulation and cyclic bleeding usually resume 60-90 days after cessation of therapy.
Uses:
Endometriosis amenable to hormonal management in clients who cannot tolerate or who have not responded to other drug therapy. Fibrocystic breast disease. Hereditary angioedema in males and females. Investigational: Gynecomastia, menorrhagia, precocious puberty, idiopathic immune thrombocytopenia, lupus-associated thrombocytopenia, and autoimmune hemolytic anemia.
Contraindications:
Undiagnosed genital bleeding; markedly impaired hepatic, renal, and cardiac function; pregnancy and lactation.
Special Concerns:
Use with caution in children treated for hereditary angioedema due to the possibility of virilization in females and precocious sexual development in males. Use with caution in conditions aggravated by fluid retention (e.g., epilepsy, migraine, cardiac, or renal dysfunction). Geriatric clients may have an increased risk of prostatic hypertrophy or prostatic carcinoma.
Side Effects:
Androgenic: Acne, decrease in breast size, oily hair and skin, weight gain, deepening of voice and hair growth, clitoral hypertrophy, testicular atrophy. Estrogen deficiency: Flushing, sweating, vaginitis, nervousness, changes in emotions. GI: N&V, constipation, gastroenteritis. Hepatic: Jaundice, dysfunction. CNS: Fatigue, tremor, headache, dizziness, sleep problems, paresthesia of extremities, anxiety, depression, appetite changes. Musculoskeletal: Muscle cramps or spasms, joint swelling or lock-up, pain in back, legs, or neck. Miscellaneous: Allergic reactions (skin rashes and rarely nasal congestion), hematuria, increased BP, chills, pelvic pain, carpal tunnel syndrome, hair loss, change in libido.
Drug Interactions:
Insulin / Insulin requirements Warfarin / PT in warfarin-stabilized clients
How Supplied:
Capsule: 50 mg, 100 mg, 200 mg
