[Change from ACE inhibitor, Ca-antagonist or beta-blocker to candesartan cilexetil: better efficacy and tolerance. SWITCH study (German study segment)]

Abstract

Background and objective: Lack of efficacy in the treatment of hypertension with only one drug presents a problem in general practice and often requires switching to another type of drug, because higher dosage of currently used antihypertensives increases the frequency of side effects. Angiotensin II antagonists are well tolerated and there is no evidence of dose-related increase in side effects. This study in 574 hypertensives under therapy with ACE inhibitors, beta-blockers or calcium channel blockers was undertaken to determine whether direct switching to the Angiotensin II-antagonist candesartan cilexetil at its maximal dose of 16 mg is as effective and tolerable as starting therapy with candesartan cilexetil 8 mg followed by up-titration to 16 mg after 4 weeks.

Patients and methods: 258 men (mean age 57 +/- 11 years) and 316 women (58 +/- 12) with essential hypertension (blood pressure < 180/95 mm Hg) under ambulatory therapy with ACE-inhibitors, beta-blockers or calcium channel blockers with inadequate efficacy or tolerability were switched to monotherapy with candesartan cilexetil. Half of the patients were treated with 8 mg for 4 weeks (n = 284), the other half received 16 mg (n = 290). Both groups then were treated with candesartan cilexetil, 16 mg, for further 4 weeks. Choice of treatment was doubly blinded and randomised.

Results: After 4 weeks significant blood pressure reduction was observed in both treatment groups (p < 0.0001 for each pretreatment group). A tendency for more adequate blood pressure reduction under initial therapy with candesartan cilexetil 16 mg was observed. There was a small further blood pressure reduction in both treatment groups after 8 weeks. In comparison with the previous medications the proportion of patients with blood pressure reduction < 90 mm Hg diastolic was doubled in both treatment arms after 4 weeks: after initial dose of candesartan cilexetil 8 mg from 36.7% to 78.8%, after initial dose of candesartan cilexetil 16 mg from 43.9% to 81.1%. Clinically relevant side effects were not observed.

Conclusion: Switching of antihypertensive monotherapy with ACE inhibitors, beta-blockers or calcium channel blockers to candesartan cilexetil 8 mg or 16 mg under ambulatory conditions is safe and equally well tolerated and effectively reduces blood pressure.