Acute inotropic effects of intravenous nifedipine and its vehicle compared with saline: a double-blind study of systolic time intervals in normal subjects

A comparison of the acute haemodynamic effects of nisoldipine and nifedipine during treatment with atenolol in patients with coronary artery disease

1. The acute haemodynamic effects of intravenous nisoldipine (1, 2, 4 microg kg(-1)) and nifedipine (2.5, 5, 10 microg kg(-1)) were compared in a randomised, within-patient crossover study. Fifteen male patients with stable angina pectoris treated with atenolol were studied after undergoing routine cardiac catheterisation. 2. Nisoldipine caused a dose-related fall in systemic vascular resistance (maximum 22%) associated with an increase in heart rate and cardiac index (18%) and a fall in mean arterial pressure (7%). 3. By contrast, nifedipine was associated with a significant increase in heart rate but systemic vascular resistance, cardiac index and mean arterial pressure remained unaltered. 4. At doses with equivalent effects on heart rate (2 microg kg(-1) nisoldipine; 10 microg kg(-1) nifedipine) acute dosing with nisoldipine caused a significantly greater fall in systemic vascular resistance and increase in cardiac index, whilst nifedipine caused a greater reduction in stroke volume index and left ventricular stroke work index. 5. The results suggest that, when combined with atenolol, acute dosing with nisoldipine may have a more complementary haemodynamic profile than nifedipine. The implications of this finding for chronic oral dosing in patients with impaired left ventricular function should be evaluated.

Comparison of the cardiovascular effects of nifedipine and nicardipine in the presence of atenolol

A placebo controlled double blind crossover study was performed in 12 healthy volunteers to compare the cardiovascular effects of single oral doses of nifedipine (5, 10 and 15 mg) and nicardipine (20 and 30 mg) in the presence of atenolol 100 mg. Haemodynamic measurements were made by transthoracic electrical bioimpedance cardiography (TEBC) 2 h following drug administration during passive tilting, graded bicycle exercise (30-150 W) and recovery from exercise. In the absence of calcium channel blockade, atenolol reduced mean blood pressure, heart rate, and cardiac index, and increased stroke volume, peripheral resistance, pre-ejection period, and ventricular ejection time, particularly during and after exercise. In comparison with atenolol alone, addition of nifedipine or nicardipine reduced peripheral resistance but did not produce significant changes in stroke volume, cardiac output, dZ/dt [max], pre-ejection period (PEP). Ventricular ejection time (VET), PEP/VET, or Heather index at any point in the experiment. Similar reductions in peripheral resistance were produced by nifedipine 10 mg and nicardipine 20 and 30 mg. These apparently equivalent doses of nifedipine and nicardipine had similar effects on stroke volume, cardiac index, PEP/VET and Heather index. Thus the increases in ventricular performance previously demonstrated in association with nifedipine and nicardipine therapy were not observed in the presence of beta-adrenoceptor blockade. Under these conditions no important differences have been observed in the cardiovascular effects of these two calcium channel blockers.

The cardiovascular effects of oral nifedipine and nicardipine: a double-blind comparison in healthy volunteers using transthoracic bioimpedance cardiography

The cardiovascular effects of single oral doses of nifedipine (5 and 10 mg) and nicardipine (20 and 30 mg) were compared in a placebo controlled double-blind crossover study involving 8 healthy male volunteers. Two hours following drug administration stroke volume and cardiac index were measured non-invasively using transthoracic electrical bioimpedance cardiography during passive tilting, graded bicycle exercise, and recovery from exercise. Two separate experiments were performed in the absence of active drug to allow the reproducibility of the measurements to be assessed. Coefficients of variation (within experiment/between experiments) for cardiac index were 7.0%/19.9% at rest and 11.5%/9.3% at 180 W exercise. Both nifedipine and nicardipine increased stroke volume and cardiac index and reduced total peripheral resistance (mean blood pressure/cardiac index) at all times in the experiment. Reductions in peripheral resistance were similar for nifedipine 10 mg and nicardipine 20 mg but in these doses slightly larger increases in heart rate were produced by nifedipine, and in stroke volume and cardiac index with nicardipine. The study shows that the cardiovascular effects of nifedipine and nicardipine can be detected using impedance cardiography which is a simple, safe, and inexpensive technique. The differences between the effects of the two drugs were small. Although some were of statistical significance and are consistent with a less marked cardiodepressant effect for nicardipine, the clinical importance of these observations is uncertain. Further studies to examine the effect of oral nifedipine and nicardipine in patients with impaired ventricular function may be helpful in clarifying this tissue.

Comparative haemodynamic effects of intravenous nisoldipine and hydralazine in congestive heart failure

The acute haemodynamic effects of intravenous nisoldipine and hydralazine were compared in nine patients with heart failure. Both agents caused qualitatively similar effects, reducing both left ventricular preload and afterload, with reductions in systemic vascular resistance and increases in cardiac output. However, the effect of hydralazine was significantly greater and of longer duration than nisoldipine, and was associated with side effects in four patients. This, and previously reported data, suggests that nisoldipine may be useful in patients with ischaemia and concomitant heart failure.