aminoglutethimide + dexamethasone

Aminoglutethimide + dexamethasone is a combination therapy used primarily in the treatment of metastatic breast cancer and Cushing's syndrome. This combination works through complementary mechanisms to inhibit steroid hormone production. ## Description Aminoglutethimide in combination with dexamethasone is a therapeutic regimen that has been used in patients with metastatic breast cancer who had prior response to hormonal manipulation and/or positive estrogen receptors[1]. The combination works by inhibiting steroid hormone synthesis, particularly estrogen production, which can fuel hormone-dependent breast cancers. Aminoglutethimide blocks several steps in steroid synthesis, including the enzymatic conversion of cholesterol to Δ5-pregnenolone and the hydroxylations required for the aromatization of androgens to estrogens[8]. This inhibition results in decreased production of adrenal glucocorticoids, mineralocorticoids, estrogens, and androgens. Dexamethasone is typically administered alongside aminoglutethimide to prevent reflex ACTH hypersecretion that would otherwise overcome the adrenal inhibition caused by aminoglutethimide[6]. However, it's important to note that aminoglutethimide accelerates the metabolism of dexamethasone, which can reduce its effectiveness[3]. ## Clinical Use In studies of metastatic breast cancer, this combination has achieved objective tumor responses (complete response plus partial response) in 19 of 44 patients (approximately 43%)[1]. Responses were observed in soft tissue, bone, and pleura, with a median duration of response of 8 months. For Cushing's syndrome, aminoglutethimide is used either alone or in combination with other medications to suppress adrenal function[10]. When used with dexamethasone, it can help manage the excessive hormone production characteristic of this condition. ## Administration Two main strategies have been employed for this combination therapy: 1. A constant dose of aminoglutethimide (1000 mg daily) combined with increasing dexamethasone dosage as needed[9] 2. Varying doses based on patient response and tolerance ## Side Effects Side effects of this combination include: - Lethargy - Skin rash - Fever - Cushingoid facies - Somnolence - Dizziness - Headache - Appetite loss - Potential liver damage - Adrenal insufficiency[4] ## Drug Interactions Important drug interactions to note: - Aminoglutethimide accelerates the metabolism of dexamethasone; therefore, if glucocorticoid replacement is needed, hydrocortisone is often preferred[3] - Aminoglutethimide diminishes the effect of coumarin anticoagulants and warfarin[3][7] - Dosages of theophylline, digitoxin, and medroxyprogesterone acetate may need to be increased when used with aminoglutethimide[4][7] This combination therapy is generally well-tolerated and represents an effective hormonal manipulation approach for appropriate patients, though it has largely been superseded by newer agents with better efficacy and lower toxicity in modern practice[4].