- Use of prescription or non-prescription drugs, including antacids, vitamins, herbal and dietary supplements (including St John's Wort and iron supplements) within 7 days (or 14 days if the drug is a potential enzyme inducer) or 5 half-lives (whichever is longer) prior to the first dose of study medication, unless in the opinion of the Investigator and sponsor the medication will not interfere with the study procedures or compromise subject safety.