QTc > 470 msec on electrocardiogram (by Bazett s; average of triplicate recordings at the discretion of the PI) will exclude patients from entry on study. Medications that are known to cause QTc interval prolongation are prohibited for patients entering on trial. Patients for whom a given medication that may cause QTc interval prolongation cannot be discontinued, may be eligible at the discretion of the study PI, provided QTc interval criteria is met at enrollment. A comprehensive list of agents with the potential to cause QTc prolongation can be found in Appendix C and at http://crediblemeds.org.