BackgroundCeftriaxone (CTX) is widely used for the treatment of bacterial infections; however, side effects such as gallstone and nephrolithiasis have been reported in children. There is limited information about urinary tract calculi as CTX side effects in adults. Therefore, the present study was aimed to evaluate the incidence of gallstone and nephrolithiasis following CTX administration.MethodsThe present study was conducted in the Vali-e-Asr Hospital. Eighty-four patients with various infectious diseases with different daily treatment (mean ± SD: 4.19±2.54) were included in this study, consisting of 49 females and 35 males. The mean of total doses used in patients was 10.2143 (SD: 5.8585). To detect possible gallstone, gallbladder sludge, and urolithiasis, patients were evaluated by serial ultrasound before and after CTX treatment. Patients with renal and hepatobiliary dysfunction were excluded from the study and did not receive any nephrotoxic drugs during this study. Demographic parameters including age, sex, body mass index, dosage of CTX, as well as the duration of treatment and hospitalization were determined. Statistical significances were determined using Fisher’s exact test and independent t-test.ResultsResults from our study showed that the incidence of gallstone and nephrolithiasis were 8.8% and 1.5% following CTX administration, respectively. Surprisingly, we found a significant correlation in terms of age between patients with and without gallstone (P=0.03).ConclusionOur findings suggest that the patients’ age might play a role in the development of such a complication. This indicates the need for a close monitoring of CTX-treated patients to assess the possible formation of gallstone and nephrolithiasis.