ENDOTHELIAL TOXICITY OF CEFTAZIDIME IN ANTERIOR-CHAMBER IRRIGATION SOLUTION

Due to the high toxicity of aminoglycoside antibiotics, many authors p refer to use third generation cephalosporines in the prophylaxis and t reatment of intraocular infections. The aim of the present study was t o determine safe ceftazidime levels in anterior chamber irrigation sol ution. Twenty-two eyes of 12 white New Zealand rabbits were divided in to six groups of two animals each. Double paracentesis was performed i n both eyes, irrigating the right eye with 250 ml of BSS-Plus (BSS +) solution, and the left eye with 250 ml of BSS + solution with increasi ng concentrations of ceftazidime (2, 3, 4, 6 and 8 mg ml(-1)). Each ra bbit was killed at the end of surgery, except the last group, which re ceived BSS + and BSS + with 8 mg ml(-1) of ceftazidime, respectively, in one eye, and were then killed 24 hr later. Endothelial lesions were assessed by silver nitrate staining. We considered lesions endothelia l silver affinity ranging hom minimal (1-2 +) to intense (3-4 +). 1-2 + silver affinity was found in 4 +/- 1.35% of endothelial cells in the controls; this percentage in turn increased with antibiotic concentra tion (6.1 +/- 1.13%, 6.7 +/- 0.4%, +/- 7.2 +/- 1.36%, 7.3 +/- 1.93% an d 7.5 +/- 1.83%, respectively). The percentage of 3-4 + silver affinit y was 0.18 +/- 0.17% in the controls, and likewise increased with anti biotic concentration (0.22 +/- 0.11%, 0.37 +/- 0.09%, 2.8 +/- 0.63% an d 3.1 +/- 0.46%, respectively). The increase in affinity was greatest up to the 4 mg ml(-1) concentration. In the last group there were zone s of endothelial alterations in morphology and size, with signs of att empted repair in the eye treated with antibiotic, but none in the case treated only with BSS +. Ceftazidime concentrations above 3 mg ml(-1) in intraocular infusions induce endothelial cell toxicity. (C) 1996 A cademic Press Limited