6. Use of drugs which are P450 3A4 inducers or inhibitors within the past 30 days (e.g. alprazolam, chlorpheniramine, cimetidine, fluoxetine, haloperidol, ketoconazole, itraconazole, erythromycin, clarithromycin, sildenafil, simvastatin, St. John's Wort);