Cost savings associated with therapeutic interchange in the treatment of mild-to-moderate hypertension

The short-term outcome and cost savings of a therapeutic interchange from calcium channel blocker (CCB) monotherapy to a fixed-dose combination of bisoprolol/hydrochlorothiazide (HCTZ) were evaluated. Sixty patients with mild-to-moderate hypertension initiated on and controlled with a single daily dose of amlodipine (n = 20), sustained-release diltiazem hydrochloride (HCl) (n = 20), or nifedipine gastrointestinal therapeutic system (GITS) (n = 20) were switched to bisoprolol/HCTZ. At the end of 3 months of follow-up after the switch, 55 of 60 (92%) patients maintained blood pressure control without dose-limiting side effects on the combination product. Mean blood pressure during CCB and bisoprolol/HCTZ treatment was not significantly different. All five treatment failures on the combination product occurred as a result of a loss of blood pressure control. Side effects were reported in 42% of patients on CCB therapy compared with 10% of bisoprolol/HCTZ therapy (P = 0.02). The cost analysis indicated that acquisition cost of the drugs was $16,868 less per year for bisoprolol/HCTZ than for CCBs. The savings were reduced by $11,724 as a result of clinic visits, laboratory testing, and side-effect management costs associated with the switch.