A multicentre study of labetalol in hypertension. New Zealand Hypertension Study Group.

Labetalol was used in a multicentre open clinical trial in 128 patients in 10 centres. Nearly half had had either poor response to other drugs or side effects with them, while another 25 percent had failed to respond satisfactorily to a diuretic alone and 35 percent were previously untreated. The results at one year showed that labetalol had an excellent antihypertensive effect, often successful in patients who had failed to respond adequately to pure beta-blockers or other drugs and it proved easy to use. Side effects necessitated stopping the drug at less than adequate dosage in some patients who might also have proved resistant to labetalol and other drugs were added to improve blood pressure control in 25 patients who continued labetalol. The mean dose of labetalol was 707 mg/day and there was no evidence of tolerance developing. Side effects were fairly common and led to withdrawal of 28 patients (22 percent).