The plasma concentration‐time profile of acetazolamide (AZ) following an intravenous bolus dose (5 mg kg‐1) was determined during control, aspirin and flurbiprofen (FLU) treatment periods. The unbound fraction of AZ in plasma increased three‐fold in the presence of salicylate (SA) while, in contrast, FLU produced consistent, but statistically insignificant, increases in binding. SA caused a two‐fold decrease in both unbound AZ renal clearance and apparent volume of distribution at steady‐state, while FLU produced a small, but significant, increase only in the latter. The area under the concentration‐time curve for AZ in erythrocytes was increased by about 40% during SA treatment while FLU had no effect. Our results suggest that on a pharmacokinetic basis FLU may be a safer nonsteroidal anti‐inflammatory drug (NSAID) to co‐ administer with AZ.