Drug Interaction Report

MONITOR: Some sulfonamides may inhibit the hepatic metabolism of hydantoins. Serum hydantoin levels and risk of toxicity may be increased. Data are available for sulfadiazine, sulfaphenazole, and sulfamethizole.

MANAGEMENT: Monitoring for clinical and laboratory evidence of altered efficacy and safety is recommended. Hydantoin dosage adjustments or an alternate antimicrobial may be required if an interaction is suspected. Patients should be advised to notify their physician if they experience symptoms of hydantoin toxicity (e.g., drowsiness, visual disturbances, change in mental status, seizures, nausea, or ataxia).

MONITOR: Two cases have been reported in which patients on sulfamethoxazole-trimethoprim therapy, after consuming beer, reported flushing, heart palpitations, dyspnea, headache, and nausea (disulfiram - alcohol type reactions). First-generation sulfonylureas have been reported to cause facial flushing when administered with alcohol by inhibiting acetaldehyde dehydrogenase and subsequently causing acetaldehyde accumulation. Since sulfamethoxazole is chemically related to first-generation sulfonylureas, a disulfiram-like reaction with products containing sulfamethoxazole is theoretically possible. However, pharmacokinetic/pharmacodynamic data are lacking and in addition, the two reported cases cannot be clearly attributed to the concomitant use of sulfamethoxazole-trimethoprim and alcohol.

MANAGEMENT: Patients should be alerted to the potential for this interaction and although the risk for this interaction is minimal, caution is recommended while taking sulfamethoxazole-trimethoprim concomitantly with alcohol.