We studied the therapeutic substitution of a less expensive but equally effective antihypertensive agent and assessed patient outcome. The medication of 39 patients with hypertension was changed from once-daily diltiazem hydrochloride (Cardizem CD) or nifedipine (Procardia XL) to felodipine (Plendil). Titration to a final dose was based on home and office blood pressure measurements assessed over subsequent follow-up clinic visits. Self-administered questionnaires measured different aspects of well-being and symptoms before and after the change in medication. Eighty percent of the cohort switched successfully to felodipine. Office systolic and diastolic pressures improved after the medication change (systolic: 150 mm Hg versus 144 mm Hg; diastolic: 92 mm Hg versus 87 mm Hg). No statistically significant differences were found among the 39 symptoms measured. A yearly savings potential for our institution was estimated to be $72,000.