Charcoal for the management of pruritus and uremic toxins in patients with chronic kidney disease

Purpose of review: Pruritus is an important, prevalent but often neglected symptom in patients with advanced chronic kidney disease (CKD) or on dialysis. This review addresses the use of activated charcoal and its analogs in the treatment of uremic pruritus, which can be a sign of uremic toxicity. Recent findings: When common causes are corrected and dialysis efficiency is optimized, pruritus is mainly ascribed to the retention of middle and protein-bound molecules, of which indoxyl sulfate and p-cresyl sulfate are the best studied. While hemodialysis and hemodiafiltration are of limited use, activated charcoal and its analogs offer interesting alternatives. Oral preparations are associated with symptom improvement and a better metabolic pattern, probably via a combination of absorption and modification of the intestinal microbiota. Large studies, in well phenotyped populations, are needed. Hemoperfusion, commonly used in poisoning and intoxication, could be an interesting alternative in hemodialysis patients. The treatment has proved promising in some preliminary and small studies; more research is now needed to test its validity. Summary: Oral activated charcoal and hemoperfusion can be proposed to patients with severe refractory pruritus based on positive, albeit scattered evidence. They also contribute to reducing uremic toxins. Research on their implementation associated with well established treatments is needed to understand whether they can be used as 'uremic detoxifiers'.