Dosage/Direction for Use
Oral Inoperable adrenocortical tumours Adult: Initially, 2-3 g daily in 2-3 divided doses; may be reduced to 1-2 g daily after 2 mth of treatment or until cumulative dose of 200 g or in the event of toxicity. If plasma monitoring is available, initial dose may be 4-6 g in divided doses to a cumulative dose of 75 g (over about 15 days). Other dose recommendation: Initially, 2-6 g daily in 3-4 divided doses; increase to 9-10 g daily unless adverse effects necessitate dose reduction. Max tolerated dose: 2-16 g daily. Child: Initially, 1.5-3.5 g/m2 daily in 2-3 divided doses; reduce after 2-3 mth depending on plasma levels. Hepatic impairment: Dose reduction may be required. Oral Cushing's syndrome Adult: 1-12 g daily. Secondary to pituitary disorders: Initially, 3-6 g daily in 3-4 divided doses. Maintenance: 500 mg twice wkly to 2 g daily. Hepatic impairment: Dose reduction may be required. |
Administration
Should be taken with food. Preferably taken during meals.
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Special Precautions
Adrenocortical insufficiency may develop; corticosteroid therapy is often required. Temporarily discontinue treatment and administer systemic corticosteroids in cases of trauma, infection or shock. Renal or hepatic impairment. Surgically remove all possible tumour tissue from large metastases prior to therapy. Perform regular behavioural and neurological assessments in patients receiving treatment for ≥2 yr. Monitor plasma levels (therapeutic window: 14-20 mcg/l). Monitor hepatic function. May affect ability to drive or operate machinery. Pregnancy and lactation.
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Adverse Reactions
CNS depression, somnolence, dizziness/vertigo, headache, confusion; skin rash; anorexia, nausea, vomiting, diarrhoea; weakness, muscle tremor; albuminuria, blurred vision, diplopia, flushing, haematuria, haemorrhagic cystitis, hypertension, hyperpyrexia, lens opacity, myalgia, orthostatic hypotension, decreased protein-bound iodine, toxic retinopathy.
Potentially Fatal: Possible permanent brain damage. |
Overdosage
Symptoms: Diarrhoea, vomiting, numbness of limbs, weakness. Management: Symptomatic and supportive.
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Drug Interactions
May reduce the effects of coumarin anticoagulants, barbiturates, phenytoin. Reduced effects with spironolactone. CNS depression may occur with alcohol.
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Food Interaction
Absorption increases with food.
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Lab Interference
Urinary tetrahydrocortisol and tetrahydrocortisone glucuronides (measurable 17-OHCS) may be reduced in the 1st several wk of mitotane therapy. May interfere with certain thyroid function tests since it competitively binds to thyroxine-binding globulin and decreases serum protein-bound iodine.
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Action
Mitotane is an antineoplastic with a selective inhibitory action on adrenal cortex activity causing tissue necrosis and atrophy. It can also modify peripheral metabolism of steroids.
Absorption: 35-40% of a dose absorbed from the GI tract; absorption increases with food. Distribution: Widely distributed and appears to be stored mainly in fatty tissues. Metabolism: Metabolised in the liver and other tissues. Excretion: Via urine and bile as metabolites. Elimination half-life: 18-159 days. |
Storage
Oral: Store at room temperature.
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CIMS Class
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ATC Classification
L01XX23 - mitotane ; Belongs to the class of other antineoplastic agents. Used in the treatment of cancer.
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