Modafinil can inhibit the action of oral contraceptives and can cause the liver to metabolize hormones faster.
Women who use low dosage oral contraceptives (steroidal drugs) should be aware that Provigil (Modafinil) may decrease the effectiveness of oral contraceptives. Experts recommend using another form of birth control while taking modafinil and for at least one month after you stop taking modafinil. Embryotoxic effects have been observed in some, but not all animal studies and there were never adequate clinical trials in pregnant women to establish safety.
A scientific study showed that the pharmacokinetics of steady-state ethinyl estradiol (ethinylestradiol) and single-dose triazolam were altered by taking Provigil. In the study, the modafinil treatment group had a marked decrease in maximum observed plasma concentrations and areas under the plasma concentration-time curve for triazolam relative to placebo, with a much smaller decrease in these parameters for ethinyl estradiol. The half-life of triazolam was also decreased, but the half-life of ethinyl estradiol did not appear to be affected by treatment with modafinil.
The researchers concluded that Modafinil induced CYP3A4/5 activity in humans in vivo, suggesting that there is potential for metabolic drug-drug interactions between modafinil and substrates of CYP3A4/5. However, the induction appeared to be more gastrointestinal than hepatic in nature.
Oral birth control pills mentioned here are also called steroid contraceptives (birth control medicines, including birth control pills and implants (e.g., Norplant) It is important that you use another method of birth control to avoid pregnancy during and for a month after modafinil therapy.
Oral and implantable contraceptives are less effective while you are taking modafinil. You should use an additional method of contraception while you are taking Provigil and for one month after discontinuing this medication.
Note also that modafinil is in pregnancy category C. The medical community feels it should only be used in pregnant or nursing women if the benefits outweigh the risks. A reassuring study in 2020 found nodafinil use is not associated with an increase in incidence of birth defects. Consult your doctor.
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