Therapeutic trials of pindolol in hypertension: comparison and combination with other drugs.

The antihypertensive effect of pindolol has been demonstrated in several hundred clinical trials performed in many countries. The results of several representative trials will be reviewed in this article. In a cooperative study of pindolol by Swiss internists, blood pressure (BP) normalization was achieved in 76% of the patients and a fair response in 9%. In a French trial, BP reduction was found to correlate with the initial pressure level. Pindolol was also found effective in treating renal hypertension (Germany) and was considered particularly useful in hypertensive patients with coexistent angina pectoris (South Africa). A favorable effect on the BP profile registered during the whole day was demonstrated by means of BP telemetry (Germany). A Swedish long-term study showed pindolol to have a sustained antihypertensive effect over 16 months associated with a progressive decrease in systemic vascular resistance. In a study conducted in New Zealand, pindolol compared favorably with drugs previously used for hypertension, (methyldopa, diuretics, rauwolfia, guanethidine, etc.). It proved slightly less effective than methyldopa in a Canadian trial but significantly more effective than this drug in a South African study. Danish investigators found pindolol equivalent to chlorthalidone in lowering the resting BP but more effective than the diuretic in reducing the pressure and pulse response to exercise. Of particular interest are comparisons of pindolol with other beta-blockers performed in Germany, Sweden, Australia, and New Zealand. BP reductions obtained with pindolol did not differ significantly from those obtained with the other beta-blockers, whether they were cardioselective (metoprolol, atenolol) or not (propranolol, timolol, nadolol); however, pindolol produced less slowing of resting heart rate than these five other drugs, which are devoid of intrinsic sympathomimetic activity (ISA). Pindolol proved somewhat more effective than other nonselective beta-blockers with ISA (i.e., oxprenolol), although both produced less bradycardia than propranolol (New Zealand). In resistant cases, the combination of pindolol with diuretics, methyldopa, or hydralazine was found to significantly increase the responder rate.