Drug-Drug Interaction Study With Pravastatin and Cyclosporine

Screening Procedures: Prior to enrollment, subjects will be asked to come to the Clinical and Translational Science (CTSI) Clinical Research Center (CRC) at San Francisco General Hospital (SFGH). The study protocol and procedures will be explained in detail, all questions will be answered, and subjects will be provided with a consent form to sign. The screening visit will be conducted within 14 days of the first inpatient visit (i.e. first pravastatin with placebo or pravastatin with cyclosporine dosing day) Only after subjects have consented to participate in the study will the screening procedures commence. During the screening visit, vital signs as well as blood sample (10 mL) will be taken by venipuncture to measure a complete blood count (CBC), electrolytes, blood urea nitrogen (BUN), creatinine, and liver function tests (LFTs) to screen for anemia and renal or hepatic insufficiency (see Inclusion/Exclusion Criteria) Procedures During Main Study: An equal number of subjects will be randomized, by a computer program, into one of the two study arms described below. On the first day of the study, subjects will be dosed with either 100 mg cyclosporine or placebo at 8PM, followed by an overnight fast. On the morning of Day 2, subjects will be asked to take a second dose of 100 mg cyclosporine or placebo at 8AM. At 9AM of Day 2, subjects will be asked to take 40 mg pravastatin. Plasma samples (5 ml) will be collected at baseline (prior to pravastatin administration), then at 0.25, 0.5, 0.75, 1, 1.5, 2, 2.5, 3, 4, 5, 6, 7, 8, 10, 12 hours post-dose. Whole blood will also be collected 12 hours post-dose to measure the cyclosporine level. The procedures during the second visit of the study will be identical to the first, but with dosing of 100 mg cyclosporine or placebo, opposite of what was dosed at the first study visit. Clinical and Laboratory Determinations: Analytical Methods: Measurement of pravastatin in plasma will be performed by High Performance Liquid Chromatography (HPLC) with tandem mass spectrometry (MS/MS), using assays previously described and validated.