The disulfiram-ethanol reaction is a well-known clinical phenomenon occurring as a result of acetaldehyde accumulation in the blood. Symptoms usually begin within 5-15 minutes after ingestion of ethanol in patients who have taken disulfiram 3-123 hours earlier, and generally occur in the following order: flushing, sweating, palpitations, dyspnea, hyperventilation, increased pulse rate, fall in blood pressure, nausea, vomiting, and drowsiness. Patients need not experience all these symptoms, and recovery is generally complete. Trimethoprim-sulfamethoxazole (cotrimoxazole) is a commonly prescribed antimicrobial agent that may produce a reaction similar to that of disulfiram when taken by patients who drink ethanol. This drug-chemical interaction may result in accumulation of acetaldehyde in the blood.