Saturday, January 28, 2006

Xenical and Coumadin

Saturday January 28, 2006
Xenical and Coumadin

Last week FDA advisory panel voted to recommend that the regulatory agency approve the nonprescription form of weight reducing agent, Xenical (orlistat), which Glaxo would market as Alli. It may be of importance to know its possible effect with warfarin (coumadin), cyclosporin and amiodarone. Orlistat is a reversible inhibitor of lipases. It forms a covalent bond with gastric and pancreatic lipases. The inactivated enzymes are thus unavailable to hydrolyze dietary fat in the form of triglycerides into absorbable free fatty acids and monoglycerides. As a side effect deficiency of fat-soluble vitamins like Vitamin A, D, E and K may occur. Recommendation is to take a multi-vitamin two hours before Xenical. Patients on coumadin (warfarin) may have potential of bleed due to increase INR (as absorption of Vitamin K is decrease). We cannot find any mention in literature describing any such real case but frequent INR check is recommended for safety. Also to remember, Xenical can decrease the amount of cyclosporine and 25-30% reduction in systemic exposure to Amiodarone. Also, there may be some concern of electrolyte imbalance with associated diarrhea. But again, we didn't find any evidence-base literature against Xenical in our search but as xenical expects to do well as over-the-counter medicine, intensivists should be ready for any potential adverse arrival in hospital.

References: Click to see abstract/article

Mechanism of Action - Orlistat -
Important Patient Information Patient Information about XENICAL -