PT  - JOURNAL ARTICLE
AU  - Christine A. Hughes, PharmD
AU  - Andrea Freitas, BSc
AU  - Lilly J. Miedzinski MD
TI  - Interaction between lopinavir/ritonavir and warfarin
AID  - 10.1503/cmaj.061284
DP  - 2007 Aug 14
TA  - Canadian Medical Association Journal
PG  - 357--359
VI  - 177
IP  - 4
4099  - http://www.cmaj.ca/content/177/4/357.short
4100  - http://www.cmaj.ca/content/177/4/357.full
SO  - CMAJ2007 Aug 14; 177
AB  - 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.