Effects of short-term oral administration of trimethoprim-sulfamethoxazole on Schirmer II tear test results in clinically normal rabbits.

Fifteen New Zealand white rabbits were used in a study to determine whether oral administration of trimethoprim-sulfamethoxazole affects the rate of tear secretion in healthy rabbits. Ten rabbits received 40 mg/kg trimethoprim-sulfamethoxazole orally twice a day for 14 days; the other five rabbits were used as a control group and received a placebo during the study. The Schirmer II tear test (STT-II) was performed in both groups during administration of the drugs or placebo on the first, third, seventh and 14th days. Significant decreases in STT-II values were observed in the treatment group on the 14th day of the study in comparison with baseline values (P<0.001).