Caffeine clearance in cirrhosis

Less complex methods of measuring hepatic metabolic capacity are needed. A simplified caffeine clearance test was evaluated in 23 patients with stable alcoholic liver disease. First, saliva caffeine concentrations were measured over a 24-h caffeine-free interval. Clearance was calculated from the rate of elimination of caffeine and an assumed volume of distribution and compared with the results of a formal clearance test using sequential plasma and saliva samples following a 300 mg oral dose. The simplified method was then assessed in 11 hospitalized patients with cirrhosis. Saliva caffeine concentrations remained measurable over the interval of study in 82% of patients. Caffeine clearance as determined by the simplified method did not differ from plasma caffeine clearance after an oral dose. Application of this method was achieved in 11 of 12 patients hospitalized for complications of severe liver disease, and revealed markedly diminished clearance. Thus, caffeine clearance can be accurately estimated in patients with severe liver disease using two or more samples of either saliva or plasma. This simplified determination of caffeine elimination rate provides a more practical assessment of hepatic metabolic capacity than a formal clearance test.