CLINICAL OUTCOME OF A MANDATORY FORMULARY SWITCH FOR DIHYDROPYRIDINE CALCIUM-CHANNEL BLOCKER THERAPY AT A VETERANS-ADMINISTRATION MEDICAL-CENTER

Recently, changes in antihypertensive therapies with similar propertie s have been made based primarily on cost savings for hospital formular ies. To assess blood pressure (BP) control and adverse side effects as sociated with a switch of patients on nifedipine GITS to felodipine at our Veteran's Administration Medical Center (VAMC), we prospectively studied physician records and patient-reported side effects (both from the medical record and patient questionnaires) in 127 hypertensive pa tients (70 +/- 10 years, 95% men, 88% nonblack, 44% with coronary dise ase) who underwent the forced switch in therapy. During the period of patient visits/chart review, physicians were unaware that the study wa s being conducted. A minimum of 2 months and two visits on each therap y was required for patient inclusion. The mean doses of nifedipine GIT S and felodipine used were 55 +/- 24 mg/day and 8 +/- 2.6 mg/day, resp ectively. The use of supplemental antihypertensive agents was similar in both calcium channel blocker groups. Systolic BPs and heart rates w ere similar in patients taking the two drugs, and the diastolic BP was modestly lower in patients taking felodipine (78 +/- 10 mm Hg for fel odipine and 80 +/- 10 mm Hg for nifedipine, P < .05). There were no di fferences in the incidence of side effects (both patient-reported and provider-reported) for the two antihypertensive therapies. These data demonstrate that in an hypertensive population followed in a VAMC, man datory switching of stable dihydropyridine calcium channel blocker the rapy did not result in any significant changes in short-term (2 to 3 m onths) BP control nor were adverse side effects different based on bot h physician- and patient-reported sources of information.