A comparison of the efficacy and duration of action of candesartan cilexetil and losartan as assessed by clinic and ambulatory blood pressure after a missed dose, in truly hypertensive patients : A placebo-controlled, forced titration study

The purpose of this double-blind, forced titration study was to compare the antihypertensive effect duration of candesartan cilexetil, which has a long-lasting binding to the human AT₁-receptor, to that of losartan on ambulatory BP (ABP) not only during the 24-h dosing interval but also during the day of a missed dose intake. After a 4-week placebo lead-in period, 268 patients with sitting diastolic BP 95 to 110 mm Hg and mean awake ambulatory DBP ≥85 mm Hg were randomized to receive either 8 mg of candesartan, 50 mg of losartan, or placebo for a 4-week period. Thereafter, the doses were doubled in all patients for an additional 4-week period. Ambulatory BP monitoring was performed for 36 h after dosing and clinic BP measured 48 h after dosing.

Candesartan cilexetil (16 mg) reduced ABP to a significantly greater extent than 100 mg of losartan, particularly for systolic ABP during daytime (P < .05), nighttime (P < .05), and 24-h (P < .01) periods, systolic (P < .01) and diastolic (P < .05) ABP between 0 and 36 h, and both systolic (P < .001) and diastolic (P < 0.001) ABP during the day of a missed dose. Clinic BP at 48 h after dosing was significantly reduced exclusively with 16 mg of candesartan. The differences in BP reduction between 8 mg of candesartan and 50 mg of losartan were statistically significant for systolic ABP during daytime (P < .01), nighttime (P < .05), 24-h (P < .01), 0 to 36 h (P < .05) and during the day of missed dose (P < .05). Moreover, although losartan did not significantly reduce ambulatory BP in a dose-related manner, ambulatory systolic and diastolic BP reductions with 16 mg of candesartan were significantly greater (P < .01 and < .001) than those seen with 8 mg of candesartan during every period at the ABP supporting a dose–response relationship.

In conclusion, this forced titration study in ambulatory hypertensive patients demonstrates that candesartan cilexetil provides significant dose-dependent reduction in both clinic and ambulatory BP in doses ranging from 8 to 16 mg once daily. Furthermore, candesartan cilexetil is superior to losartan in reducing systolic ABP and in controlling both systolic and diastolic ABP on the day of a missed dose. The differences observed between both agents are most likely attributable to a tighter binding to, and a slower dissociation from, the receptor binding site with candesartan cilexetil.