AMINOGLUTETHIMIDE
(a-mee-noe-gloo-teth'i-mide)
Cytadren
Classifications: antineoplastic aromatase inhibitor
Pregnancy Category: D

Availability

250 mg tablets

Actions

Blocks adrenal corticosteroid biosynthesis by inhibiting enzymatic conversion of cholesterol to precursors of cortisol and aldosterone. Also blocks aromatase, thereby preventing conversion of androgens to estrogens in peripheral tissues.

Therapeutic Effects

Because estrogens are supplied principally by the adrenals in postmenopausal and oophorectomized women, aminoglutethimide-induced lowering of plasma estrogen levels (by adrenal suppression) is reportedly as effective as that produced by surgical adrenalectomy.

Uses

Temporary treatment of selected patients with Cushing's syndrome associated with adrenal carcinoma, ectopic ACTH-producing tumors, or adrenal hyperplasia.

Unlabeled Uses

To produce medical adrenalectomy in postmenopausal women with positive estrogen receptor test, metastatic breast cancer, or who fail or relapse with tamoxifen (Nolvadex), and for patients with prostatic carcinoma.

Contraindications

Hypothyroidism; infection. Safety during pregnancy (category D), lactation, and in children is not established.

Cautious Use

Older adults.

Route & Dosage

Cushing's Disease
Adult: PO 250 mg q6h, may be increased 250 mg/d q1–2wk if needed (max: 2 g/d)

Breast Cancer
Adult: PO 250 mg b.i.d. and hydrocortisone 60 mg h.s., 20 mg in a.m., and 20 mg at 2 p.m. daily for 2 wk, then 250 mg q.i.d. and hydrocortisone 20 mg h.s., 10 mg in a.m., and 10 mg at 2 p.m. thereafter

Administration

Oral

Adverse Effects (1%)

CNS: Lethargy, drowsiness, dizziness, uncontrolled eye movements (dose related); clumsiness, headache. CV: Hypotension, tachycardia. Endocrine: Masculinization. GI: Nausea, vomiting, anorexia, hepatotoxicity. Hematologic: (Rare) Neutropenia, leukopenia, thrombocytopenia, pancytopenia, agranulo-cytosis, decreased Hgb and Hct, anemia, Coombs' negative hemolytic anemia. Skin: Measles-like (morbilliform) rash, pruritus.

Interactions

Drug: Dexamethasone decreases pharmacologic effects of aminoglutethimide; decreases anticoagulant response to warfarin.

Pharmacokinetics

Onset: 3–5 d. Distribution: Crosses placenta. Metabolism: Hepatic metabolism. Elimination: Excreted by kidneys; recovery of adrenal responsiveness to stress occurs 36–72 h after discontinuation. Half-Life: 13 h (7 h with long-term use).

Nursing Implications

Assessment & Drug Effects

Patient & Family Education


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