<qa>  What is the name of the drug that is used to treat patients who have been off the drug14. Patients receiving ketoconazole, erythromycin, verapamil, diazepam, quinidine, diltiazem, rifampicin, carbamazepine, phenytoin, efavirenz, nevirapine, fluoxetine or gemfibrozil. Patients taking any of these drugs may qualify for treatment on this investigational study if they have been off the drug at least for 7 days. 