Influence of hepatic dysfunction on the pharmacokinetics of propafenone

Hepatic metabolism is the primary process of elimination of propafenone. It therefore is important to understand the effect of altered liver function on the disposition and elimination kinetics of this drug. Patients with abnormal liver function probably will require treatment with propafenone for cardiac arrhythmias; an understanding of the relationship between liver function and the pharmacokinetics of propafenone will provide a rational basis for optimal dosage adjustments in these individuals. Our results demonstrate that both systemic clearance and bioavailability of propafenone are sensitive to variability in liver function. The bioavailability of propafenone is inversely related to the clearance of indocyanine green (ICG), whereas a direct relationship exists between systemic clearance of propafenone and ICG clearance. Comparisons of clinical parameters with the propafenone data yielded interesting results. An overall clinical grading of severity of liver disease based on the presence or absence of portal hypertension (i.e., varices and/or splenomegaly), prior encephalopathy, and ascites did not correlate well with propafenone results. However, albumin, total bilirubin, serum glutamic oxaloacetic transaminase (SGOT) concentrations and prothrombin time values correlated strongly with the overall results. No definite relationships with subjects' age; weight; and hemoglobin, alkaline phosphatase, lactic acid dehydrogenose, cholesterol, blood urea nitrogen, or creatinine levels were detected. These results demonstrate that moderate to severe liver disease significantly affects the absorption and disposition of propafenone. In patients with cirrhosis, and presumably other forms of hepatic dysfunction, careful adjustments of propafenone doses are needed to optimize therapy.