• primary biliary cirrhosis
• rifampicin
• cholestatic pruritus

Prince et al described three patients with primary biliary cirrhosis who developed hepatotoxicity when given rifampicin to treat their cholestatic pruritus (Gut 2002;50:436–9). They describe the use of rifampicin as “secondline” treatment of cholestatic pruritus. Firstline therapy is generally considered to be cholestyramine, a bile acid sequestrant. Use of this agent is frequently unsatisfactory because of gastrointestinal side effects, especially constipation. I am writing to summarise new evidence that retention of endogenous bile acids causes cholestatic pruritus, and to call attention to a recent abstract indicating that colesevalem, a new bile acid sequestrant, appears to be more potent than cholestyramine and does not induce constipation.

The view that bile acid retention causes pruritus is a very old one. Varco¹ in 1947 noted that biliary drainage reduced pruritus in patients with extrahepatic biliary obstruction and that when bile was fed to patients, their pruritus returned. Huet and colleagues² reported that biliary drainage improved cholestatic pruritus in patients with intrahepatic cholestasis. Administration of cholestyramine, an anion exchange resin with a strong affinity …