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