- Use of prescription or nonprescription drugs, and dietary supplements within 7 days or 5 half-lives (whichever is longer) prior to the first dose of study medication. Herbal supplements and hormonal replacement therapy must be discontinued 28 days prior to the first dose of study medication. As an exception, ibuprofen may be used at doses of up to 1800 mg/day with food. Limited use of non-prescription medications that are not believed to affect subject safety or overall results of the study may be permitted on a case -by-case basis following approval by the sponsor.