The effect of acetazolamide on the kinetics of four newer beta-lactams in the aqueous humor

Objective To evaluate whether the effect of acetazolamide on piperacillin's aqueous humor concentrations observed in animals exists also in humans for ceftazidime, cefotaxime, ceftriaxone and aztreonam. Methods One hundred and eighty-eight patients undergoing eye cataract surge ry were randomly allocated to receive intravenous ceftazidime, cefotaxime, aztreonam or ceftriaxone with (subgroup A) or without (subgroup B) concomit ant oral administration of acetazolamide. Antibiotic concentrations in seru m and the aqueous humor, simultaneously sampled during the operation, were measured using an agar well diffusion technique, and the ratios of the conc entrations of aqueous humor to serum were calculated and compared. Statisti cal analysis was performed by using the paired t-test. Results Mean aqueous humor ceftazidime concentrations at 2, 4, and 6 h were 24.65, 16.4 and 8.6 mg/L (subgroup A), and 4.26, 8.66 and 5.61 mg/L (subgr oup B). Corresponding concentrations of cefotaxime were 1.75, 1.0 and 0.77 mg/L (subgroup A), and 1.11, 0.81 and 0.58 mg/L (subgroup B), and of aztreo nam 6.9, 5.84 and 3.61 mg/L (subgroup A), and 3.38, 2.57 and 1.48 mg/L (sub group B). Ceftriaxone concentrations at 2, 4, 6 and 12 h were 1.78, 1.49, 1 .57 and 1.41 mg/L (subgroup A), and 1.35, 0.95, 1.08 and 0.85 mg/L (subgrou p B). The differences in aqueous humor concentrations when acetazolamide wa s administered were statistically significant (P < 0.05), with the exceptio n of ceftazidime 6 h, cefotaxime 6 h and ceftriaxone 2 h. Conclusions Although acetazolamide resulted in statistically significant in creases in the aqueous humor concentrations of all the antibiotics tested, this effect was most marked for ceftazidime.