Drug Interaction Report

MONITOR: Coadministration with inhibitors of CYP450 2C9 may increase the plasma concentrations of celecoxib, which is primarily metabolized by the isoenzyme. The possibility of prolonged and/or increased pharmacologic effects of celecoxib should be considered.

MANAGEMENT: Clinical monitoring for altered effects of celecoxib is recommended following initiation or discontinuation of a CYP450 2C9 inhibitor. Dosage adjustments may be required if an interaction is suspected. Patients should be advised to notify their physician if they experience potential signs and symptoms of celecoxib toxicity such as abdominal pain, black or tarry stools, nausea, vomiting, lethargy, fluid retention, swelling of legs, and worsening heart failure.

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.