A new test called the erythromycin breath test will be administered to you three times during the study to measure how your liver will metabolize these drugs. Blood samples will also be obtained to assess platelet function. The criteria for exclusion are patient refusal or inability to give written consent, patients with allergic reaction to erythromycin, patients with known bleeding problems, liver disease, significant lung disease kidney disease and pregnancy. Patients with psychiatric impairment and documented history of substance abuse will also be excluded from the study.