Urlyx/Urlyx 500 Drug Interactions

Urlyx: Ursodeoxycholic acid should not be used with drugs that increase bile cholesterol such as estrogenic hormones and cholesterol-lowering drug such as clofibrate. Use with bile-acid binding drugs including antacids, charcoal, and cholestyramine should be avoided since this may reduce the effectiveness of therapy with ursodeoxycholic acid.
Urlyx 500: Ursodeoxycholic acid should not be administered concomitantly with colestyramine, colestipol or antacids containing aluminum hydroxide and/or smectite (aluminum oxide), because these preparations bind ursodeoxycholic acid in the intestine and thereby inhibit absorption and efficacy. Should the use of a preparation containing one of these substances be necessary, it must be taken at least 2 hours before or after Ursodeoxycholic acid. Ursodeoxycholic acid can affect the absorption of ciclosporin from the intestine. In patients receiving ciclosporin treatment, blood concentrations of this substance should therefore be checked by the physician and the ciclosporin dose adjusted if necessary. Due to the effect of UDCA on the secretion of bile acids there is a theoretical possibility that the absorption of other lipophilic substances could be affected. In certain rare cases Ursodeoxycholic acid can reduce the absorption of ciprofloxacin. Ursodeoxycholic acid has been shown to reduce the plasma peak concentrations Cmax nitrendipine in healthy volunteers. Close monitoring of the outcome of concurrent use of nitrendipine and UDCA is recommended. An increase of dose may be necessary. An interaction with a reduction of the therapeutic effect of dapsone was also reported. These two interactions in addition to shown in vitro interaction could be explained by enzyme induction with CYP3A4. However, no induction was observed in a well-designed interaction study with budesonide. Oestrogenic hormones and blood cholesterol lowering agents such as clofibrate increase hepatic cholesterol secretion and may encourage biliary lithiasis, which is a counter-effect to ursodeoxycholic acid used for dissolution of gallstones. A clinical study on healthy volunteers with concomitant use of UDCA (500 mg/day) and rosuvastatin. The clinical relevance of this interaction and even the interactions concerning other statins are unknown.