TY - JOUR T1 - Interaction between lopinavir/ritonavir and warfarin JF - Canadian Medical Association Journal JO - CMAJ SP - 357 LP - 359 DO - 10.1503/cmaj.061284 VL - 177 IS - 4 AU - Christine A. Hughes, PharmD AU - Andrea Freitas, BSc AU - Lilly J. Miedzinski MD Y1 - 2007/08/14 UR - http://www.cmaj.ca/content/177/4/357.abstract N2 - Drug interactions involving protease inhibitors are common. Protease inhibitors are well known inhibitors of the 3A4 isozyme of cytochrome P450. Select protease inhibitors, including co-formulated lopinavir/ritonavir, may induce glucuronidation or the activity of other CYP450 isozymes. We describe the case of a patient taking warfarin who experienced a significantly decreased international normalized ratio after the initiation of antiretroviral therapy that included lopinavir/ritonavir. We review the possible mechanisms of this interaction and the reported interactions between warfarin and other protease inhibitors. ER -