<qa>  What is the effect of cytochrome P450 interactions on women?7. Women who are pregnant or breast feeding, or womenmen able to conceive and unwilling to practice an effective method of birth control throughout the trial and for 8 weeks after the last dose of study drug. Women of childbearing potential must have a negative pregnancy test. Oral, implantable, or injectable contraceptives may be affected by cytochrome P450 interactions, and are therefore not considered effective for this study. 