Pellegrino AM, et al. - Given a recent approval of tolvaptan use, a V₂-receptor antagonist, in patients with autosomal dominant polycystic kidney disease (ADPKD), and in view of the finding that tolvaptan get slower drop in Kidney function vs placebo, and idiosyncratic hepatic toxicity was reported in patients taking tolvaptan, with rises in aminotransferases concentrations, researchers report the first case published in the literature wherein the cause of the hepatic toxicity was the link of amoxicillin/clavulanic acid and tolvaptan. They examined a 41 years old woman who was treated with tolvaptan for 16 weeks for ADPKD when a rise of liver enzyme levels was identified. Approximately 5 weeks before, she had received autonomously amoxicillin/clavulanic acid (in doses of 825/175 mg twice a day for 7 days). The concomitance of medication of tolvaptan and amoxicillin/clavulanic acid could be held responsible for the timing of the event and the kind of hepatocellular injury. Among ADPKD patients in treatment with tolvaptan and amoxicillin/clavulanic acid, the requirement to careful monitor hepatic enzyme levels was highlighted for the detection of early hepatic side effects.