Drug Interaction Report

GENERALLY AVOID: Coadministration of topical chloramphenicol with other agents that can cause bone marrow depression, aplastic anemia, or agranulocytosis may increase the risk and/or severity of hematologic toxicity. Chloramphenicol may be absorbed systemically from the eye, ear, and vagina. Bone marrow hypoplasia, including aplastic anemia and death, has been reported following topical use of chloramphenicol. However, systemic absorption following topical, ophthalmic, otic, and vaginal administration is generally minimal, and data concerning the incidence of blood dyscrasias following the use of topical chloramphenicol are not available.

MANAGEMENT: Concurrent use of topical chloramphenicol formulations with other bone marrow depressing agents should generally be avoided. If concomitant use on a long-term or intermittent basis is considered necessary, patients should be monitored for the development of hematologic adverse effects. Monitoring via full blood counts before and periodically during therapy may also be advisable.

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.