- Use of non-prescription drugs, including vitamins, herbal and dietary supplements (including St John's Wort) 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 drug (Day 1) through the Follow-up Visit (Day 65), unless, in the opinion of the Investigator, medication will not interfere with the study procedures or compromise subject safety and GSK Medical Monitor concurs.