The physical compatibility of bivalirudin (Angiomax) with 96 selected other drugs during simulated Y-site injection was evaluated by visual observation, turbidity measurement, and electronic particle content assessment (when appropriate). Five-milliliter samples of bivalirudin 5mg/mL in 5% dextrose injection were combined with 5mL of 96 other drugs (anti-infectives, analgesics, anihistamines, diuretics, steroids, or other supportive-care drugs that were either undiluted or diluted with either 5% dextrose injection or 0.9% sodium chloride injection [the diluent for drugs incompatible with 5% dextrose injection ]). Visual examinations were performed with the unaided eye in normal, diffuse fluorescent light with a Tydall beam (a high-intensity monodirectional light beam) to enhance the visualization of small particles and low-level turbidity. The turbidity of each sample was measured as well. The particle content of samples that did not exhibit a visible incompatibility was measured. Evaluation of the samples was performed initially and at 1 and 4 hours after preparation. Eighty-seven of the 96 test drugs were compatible with the bivalirudin dilution during the 4-hour observation period. However, the combination of bivalirudin solution with each of nine drugs resulted in haze formation, microparticulate formation, or gross preciptiation. Bivalirudin should not be administered simultaneously with those incompatible drugs.