The effect of ranitidine on the plasma clearance and hepatic extraction of indocyanine green in patients with chronic liver disease.

Since hepatic clearance of ICG is reduced by H2-receptor antagonists in normal subjects, it has been suggested that they reduce liver blood flow. We have studied the effect of intravenous ranitidine on ICG clearance in twelve patients with chronic liver disease. Wedged and free hepatic venous pressure were measured before and after intravenous ranitidine in nine of the patients, and the hepatic extraction of ICG was determined in six patients. ICG clearance fell by 22 +/- 11% (s.e. mean) 60 min after ranitidine. In patients in whom ICG clearance fell after intravenous ranitidine the hepatic extraction of ICG was also reduced. There was no significant change in the gradient between wedged and free hepatic venous pressure after ranitidine. It is therefore unlikely that ranitidine lowers liver blood flow.