Irbesartan: CLINICAL IMPLICATIONS(1)
Comparative antihypertensive effects of ARBs
Because losartan was the first approved ARB, it has become an important benchmark for within-class comparisons with respect to antihypertensive effect. As such, six trials have been conducted to date comparing the antihypertensive effects of losartan with other ARBs. Table 2 reviews these studies, comprising two comparative studies with irbesartan, two with candesartan, and one each with valsartan and eprosartan.
When comparing the data in Table 2, it is important to bear in mind some critical differences in study designs and outcomes. Of the six studies, the comparative study of telmisartan and one of the studies with candesartan did not evaluate the maximum dose of losartan 100 mg, and consequently the results should not be weighted as heavily as those obtained from the remaining studies . Of the remaining results, the comparative study with valsartan found no statistically significant difference in terms of reduction in DBP at week 8 (the primary endpoint) between the maximum doses of valsartan and losartan. It is, therefore, important to note that only irbesartan has been demonstrated to provide statistically superior reductions in blood pressure compared with the maximum dose of losartan in two independent studies (Figure 3) . Similar results were obtained in only one of the two comparative studies with candesartan. ventolin inhaler
TABLE 2 Comparative studies of angiotensin II type 1 receptor blockers
*Group randomly assigned to the highest dose
Figure 3) Comparative efficacy in reducing seated diastolic blood pressure (SeDBP) with irbesartan 300 mg (■) and losartan 100 mg (A). ♦ Placebo; • Irbesartan 150 mg. n=567; *P<0.01 irbesartan 300 mg versus losartan 100 mg; tP<0.017 irbesartan 300 mg versus losartan 100 mg. Data from reference 6