Abstract Introduction As patients who receive cannabidiol (CBD) may have co-existing renal morbidities, it is important to understand whether dose adjustments are necessary to mitigate the risk of exposure-related toxicity. This study was conducted to evaluate the pharmacokinetics, safety, and tolerability of CBD in patients with renal impairment. Methods The pharmacokinetics and safety of a single oral 200 mg dose of a plant-derived pharmaceutical formulation of highly purified CBD in oral solution (Epidiolex® in the USA; 100 mg/mL) were assessed in subjects with mild, moderate, or severe renal impairment (n = 8/group) relative to matched subjects with normal renal function (n = 8). Blood samples were collected until 48 h post-dose and...