- Unable to refrain from the use of prescription drugs (except contraceptives and HRT) or non-prescription drugs (except acetaminophen), including vitamins, herbal and dietary supplements from 7 days before the first dose of study medication until the follow-up visit, unless in the opinion of the Investigator and GlaxoSmithKline (GSK) Medical Monitor the medication will not interfere with the study procedure or compromise subject safety.