Potent hemodynamic effects of bimakalim, a new potassium channel opener, in humans.

The cardiac hemodynamic effects of bimakalim, a new potassium channel opener, were evaluated in 12 normal volunteers by echocardiography (ECHO)/Doppler in a placebo-controlled, randomized double-blind, cross-over, dose-ranging study. A single oral dose (0.25-1 mg) was given at weekly intervals. Hemodynamic measurements were made at 0, 90, 120, and 240 min after drug intake and ECHO/Doppler was performed at 0 and 90 min. Reproducibility of the ECHO/Doppler study was assessed by comparing predose baseline values of the four different phases of treatment (placebo and 0.25, 0.5, and 1 mg) by analysis of variance (ANOVA), which showed no significant differences for left ventricular ejection fraction (LVEF). Doppler-derived stroke volume (SV), total peripheral resistance (TPR), and peak mitral early to late velocity ratio (PEV/PAV). ANOVA showed significant increases in LVEF (p = 0.0003) and SV (p = 0.03), however, and decreases in TPR (p = 0.002) and PEV/PAV (p = 0.005) after bimakalim treatment. Heart rate (HR) showed a dose-dependent increase, but systolic and diastolic blood pressure (SBP, DBP) did not change with bimakalim. Despite vasodilatory headaches, none of the volunteers discontinued the study. Bimakalim appears to be a potent vasodilating drug that may have an important role in management of patients with compromised LV function.

Comparison of the safety and efficacy of bisoprolol versus atenolol in stable exercise-induced angina pectoris: a Multicenter International Randomized Study of Angina Pectoris (MIRSA).

Bisoprolol 10 mg and atenolol 100 mg once daily were compared regarding efficacy and safety in stable effort angina in a 12-week, multicenter, double-blind, randomized, parallel-group study. Efficacy was evaluated with angina pectoris diaries and bicycle exercise tests. Spontaneously mentioned complaints and side effects were recorded at each visit. In 11 centers, 147 patients completed the study; 76 received bisoprolol 10 mg, and 71 received atenolol 100 mg. After 12 weeks, weekly anginal attack rate was reduced significantly (p less than 0.05) with bisoprolol (5 +/- 0.5 to 2 +/- 0.6) and with atenolol (4 +/- 0.4 to 1 +/- 0.2). Peak exercise capacity (in W x min) increased significantly (p less than 0.05) with bisoprolol (772 +/- 47 to 878 +/- 52) and with atenolol (891 +/- 46 to 986 +/- 53). Rate pressure product (RPP) at peak exercise (in beats/min x mm Hg) decreased significantly (p less than 0.05) with both bisoprolol (25,003 +/- 692 to 20,116 +/- 637) and atenolol (26,544 +/- 557 to 21,603 +/- 576) (all values are mean +/- SE). The differences between the groups were not statistically significant. There were no significant differences regarding nature and incidence of adverse events between the groups. Thus, bisoprolol 10 mg once daily and atenolol 100 mg once daily are equipotent in their effects on stable effort angina. Both regimens were comparable with respect to incidence and nature of side effects.