 - Eligibility of patients receiving medications or substances known to affect, or with the potential to affect the activity or pharmacokinetics of GW572016 will be determined following review of their use by the Principal Investigator; patients requiring oral anticoagulants coumadin, warfarin are eligible provided there is increased vigilance with respect to monitoring international normalized ratio INR; if medically appropriate and treatment available, the investigator may also consider switching these patients to low molecular weight LMW heparin, where an interaction with GW572016 is not expected 