Severe and sometimes fatal hepatitis or hepatic failure associated with therapy may develop and may occur with or without prior history of abnormal hepatic function. In individuals who ingest alcohol while receiving disulfiram, the drug produces an adverse disulfiram-alcohol reaction which may persist for 30 minutes to several hours, or as long as alcohol remains in the blood. Adverse nervous system effects have been produced by low doses of disulfiram in patients with no previous history of neurologic illness (e.g. vertigo, irritability, insomnia, abnormal gait, slurred speech, disorientation, confusion, personality changes, tonic-clonic (Grand mal) seizures, peripheral neuropathy, polyneuritis, optic neuritis, delirium, bizarre behavior, drowsiness, and psychoses). Sudden withdrawal from alcohol itself may disclose a preexisting neurologic disorder. Disulfiram may aggravate preexisting EEG abnormalities. Disulfiram itself may produce adverse effects in the absence of alcohol, especially during the first 2 weeks of therapy (e.g. fatigue, impotence, headache, acneiform or allergic dermatitis, and a metallic or garlic-like aftertaste may occur), but usually disappear with continued therapy or temporary dosage reduction. The drug has rarely caused blood dyscrasias. Patients receiving disulfiram should be warned to avoid other preparations which contain alcohol (may produce a disulfiram-alcohol reaction). Hepatic toxicity, including hepatic failure resulting in transplantation or death, and blood dyscrasias reported. Disulfiram should be given with caution, if at all, to patients with diabetes mellitus, hypothyroidism, seizure disorders, cerebral damage, chronic or acute nephritis, hepatic cirrhosis or insufficiency, abnormal EEG results, or multiple drug dependence. Disulfiram is contraindicated in alcohol intoxication, cardiovascular disease, or psychoses. Disulfiram is also contraindicated in individuals hypersensitive to the drug or other thiuram derivatives such as those used in pesticides or rubber vulcanization. Administration of any medications containing alcohol, including topicals, is contraindicated. Disulfiram administration should be avoided if ethanol has been consumed within the prior 12 hours.