Chronic pain is a major therapeutic problem in kidney transplant patients owing to nephrotoxicity associated with nonsteroidal antiiflammatory drugs. Benefits in chronic pain treatment with cannabidiol (CBD) have been reported. This study assesses the effect, safety, and possible drug interactions in kidney transplant patients treated with CBD for chronic pain.
We assessed patients who asked to receive CBD for pain treatment. Doses were increased from 50 to 150 mg twice a day for 3 weeks. Creatinine, blood count, liver function, liver enzymes, and drug levels were determined every 48 hours the first week and then once a week thereafter.
We assessed 7 patients with a mean age of 64.5 years (range, 58-75 years). CBD initial dose was 100 mg/d, CBD dose reduction to 50 mg/d has been done on day 4 to patient 1 for persistent nausea. Tacrolimus dose reduction in patient 3 was undertaken on days 4, 7, and 21 owing to persisting elevated levels (even before CBD) and itching, and on day 21 in patient 5. Tacrolimus levels decreased in patient 2 but were normal in the control 1 week later. Patients on cyclosporine were stable. Adverse effects were nausea, dry mouth, dizziness, drowsiness, and intermittent episodes of heat. CBD dose decrease was required in 2 patients. Two patients had total pain improvement, 4 had a partial response in the first 15 days, and in 1 there was no change.
During this follow-up, CBD was well-tolerated, and there were no severe adverse effects. Plasma levels of tacrolimus were variable. Therefore, longer follow-up is required.