Drug Interaction Report

GENERALLY AVOID: The pharmacologic activity of oral midazolam, triazolam, and alprazolam may be increased if taken after drinking grapefruit juice. The proposed mechanism is CYP450 3A4 enzyme inhibition. In addition, acute alcohol ingestion may potentiate CNS depression and other CNS effects of many benzodiazepines. Tolerance may develop with chronic ethanol use. The mechanism may be decreased clearance of the benzodiazepines because of CYP450 hepatic enzyme inhibition. Also, it has been suggested that the cognitive deficits induced by benzodiazepines may be increased in patients who chronically consume large amounts of alcohol.

MANAGEMENT: The manufacturer recommends that grapefruit juice should not be taken with oral midazolam. Patients taking triazolam or alprazolam should be monitored for excessive sedation. Alternatively, the patient could consume orange juice which does not interact with these drugs. Patients should be advised to avoid alcohol during benzodiazepine therapy.

GENERALLY AVOID: Some cephalosporins may occasionally induce a disulfiram-like reaction when coadministered with alcohol. The interaction has been reported for cefamandole, cefoperazone, cefotetan, and moxalactam. These agents contain an N-methylthiotetrazole (NMTT) side chain that may inhibit aldehyde dehydrogenase (ALDH) similar to disulfiram. Following ingestion of alcohol, inhibition of ALDH results in increased concentration of acetaldehyde, the accumulation of which produces an unpleasant physiologic response referred to as the 'disulfiram reaction'. Symptoms include flushing, throbbing in head and neck, throbbing headache, respiratory difficulty, nausea, vomiting, sweating, thirst, chest pain, palpitation, dyspnea, hyperventilation, tachycardia, hypotension, syncope, weakness, vertigo, blurred vision, and confusion. Severe reactions may result in respiratory depression, cardiovascular collapse, arrhythmias, myocardial infarction, acute congestive heart failure, unconsciousness, convulsions, and death. Cefonicid contains a structurally similar side chain but did not produce elevations in blood acetaldehyde or a disulfiram reaction to ethanol in 15 healthy volunteers given single and multiple one gram doses of the drug.

MANAGEMENT: Patients receiving cephalosporins with the NMTT side chain should avoid the concomitant use of alcohol and alcohol-containing products.