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Action/Kinetics:
Directly suppresses activity of adrenal cortex and changes the peripheral metabolism of corticosteroids, resulting in a decrease in 17-hydroxycorticosteroids. About 40% absorbed from GI tract; detectable in serum for 6-9 weeks after administration. Mostly stored in adipose tissue.
t
1/2: After therapy terminated, 18-159 days. Unchanged drug is excreted in the feces while metabolites are excreted in the urine. Steroid replacement therapy may have to be instituted (i.e., increased) to correct adrenal insufficiency. Therapy is continued as long as drug seems effective. Beneficial results may not become apparent until after 3 months of therapy.
Uses:
Inoperable carcinoma (both functional and nonfunctional) of the adrenal cortex.
Investigational: Cushing's syndrome.
Contraindications:
Hypersensitivity to drug. Discontinue temporarily after shock or severe trauma. Lactation.
Special Concerns:
Use with caution in the presence of liver disease other than metastatic lesions. Long-term usage may cause brain damage and functional impairment.
Side Effects:
CNS: Continuous doses may result in brain damage and impairment of function. Depression, lethargy, somnolence, dizziness, vertigo.
GI: N&V;, anorexia, diarrhea.
CV: Hypertension, orthostatic hypotension, flushing.
Dermatologic: Transient skin rashes.
Ophthalmic: Visual blurring, diplopia, lens opacity, toxic retinopathy.
GU: Hematuria, hemorrhagic cystitis, albuminuria.
Miscellaneous: Adrenal insufficiency, generalized aching, hyperpyrexia.
Laboratory Test Alterations:
PBI and urinary 17-hydroxycorticosteroids.
Drug Interactions:
-
Corticosteroids /
Corticosteroid metabolism
need for /
doses
-
Warfarin /
Rate of warfarin metabolism
need for
dosage
How Supplied:
Tablet: 500 mg
Dosage
?Tablets
Carcinoma of the adrenal cortex.
Adults, initial: 2-6 g/day in three to four equally divided doses; increase dose incrementally to 9-10 g/day (maxiumum tolerated dose: 2-16 g/day). Adjust dosage upward or downward according to severity of side effects or lack thereof.
Pediatric, initial: 1-2 g/day in divided doses;
then, dose can be increased gradually to 5-7 g/day.
Cushing's syndrome.
Initial: 3-6 g/day in three to four divided doses;
then, 0.5 mg 2 times/week to 2 g/day.
