Modafinil Warfarin

ANTICOAGULANTS-ORAL CNS STIMULANTS -MODAFINIL May cause moderate T plasma concentrations of warfarin Modafinil is a reversible inhibitor of CYP2C9 and CYP2C19 when used in therapeutic doses Be aware... 

The manufacturers caution if enzyme-inducing anticonvulsants, particularly phenytoin, are used with modafiniL There is speculation, based on in vitro studies, about some possible interactions with other drugs, such as warfarin. Modafinil is an inducer of CYP3A4 and therefore may be expected to interact with substrates of this isoenzyme. 

There is no clinical evidence of an interaction between warfarin and mo-dafmil, but because warfarin is, in part, metabolised by the cytochrome P450 isoenzyme CYP2C9 (which is inhibited by modafinil) the manufacturers suggest that concurrent use should be monitored for the first 2 months of concurrent use. ... 

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