[Treatment of arterial hypertension with labetalol. A polycentric study].

One hundred and fifty-seven hypertensive patients (1st and 2nd degree of the WHO classification) studied in 15 hospitals were treated with labetalol at a dosage of 300-600 mg a day for 3 months. Nineteen patients did not complete the study because of the appearance of side effects, because of failure of the treatment to decrease the blood pressure, or for other reasons. Of the remaining 138 patients, 77 were treated with labetalol only, while in 61 a diuretic was added. The mean value of the systolic pressure decreased from 173 to 145 mmHg in the recumbent position and from 170 to 140 mmHg in the upright position. The diastolic pressure decreased from 111 to 92 mmHg in the recumbent position and from 113 to 92 mmHg in the upright position. All these differences are statistically significant (p less than 0,001). Heart rate was significantly reduced from 77 to 70 beats per minute in recumbent position and from 82 to 75 in the upright position, according to the action of the drug on the alpha and beta-receptors. Side-effects were mild and prompted the interruption of treatment in 3.2% of the patients. In conclusion this polycentric research confirms that labetalol has a good antihypertensive effect in patients with mild or moderate hypertension and that this effect can be achieved with a dosage equal or inferior to 600 mg a day. If with this dosage a satisfactory blood pressure level is not obtained, it is advisable to add a diuretic. With this combined treatment more than two thirds of cases (71%) have been satisfactorily controlled. The drug was well tolerated and postural hypotension was nearly always absent.