WHAT IS THE ROLE OF LABETALOL IN ANTIHYPERTENSIVE THERAPY?

Compared with propranolol in mild to moderate hypertension Labetalol (Trandate'; Allen & Hanburys) and propranolol both lowered BP satisfactorily in the supine position in a double-blind study in patients with previously untreated mild to moderate hypertension. However, labetalol reduced BP more than propranolol in the erect posture and after exercise, and induced less bradycardia. 1 I patients completed the study on a final mean dose of labetalol of 1180mg/ day and propranolol 480mgi day. The ratio oflabetalol to propranolol was 2.45: 1 w /w. Heart rates with labetalol were slower than with placebo but faster than with propranolol. Side effects during the 1 O-week therapy were fewer with both drugs than placebo in the early part of the study, a trend reversed in the last 3 weeks. Incidence of reactions was similar (12 patients). Two patients complained of ejaculation difficulty with labetalol and one of postural dizziness when the dose was raised. With propranolol there were 2 cases of Raynaud's phenomenon and 2 of gastrointestinal disturbances. Haemoglobin values were reducedafter·labetalol. Pugsley, DJ. et al.: British Journal of Clinical Pharmacology 7: 63 (Jan 1979)

In general practice, BP control seems easier to achieve with labetalol Labetalol offered several therapeutic advantages to both physician and patient in a general practice study in 163 patients with hypertension treated with labetalol for up to 3 months. Control ofBP was achieved easily, at a lower level than with previous therapy, with fewer incremental dose changes and often with a single drug, although previous medication was continued in some patients. Mean dosage oflabetalol at the start of the study was 399mg daily and 420mg at the end of 3 months. 10 patients had a diuretic added but no other antihypertensive drugs were necessary. 72 (44 %) of the patients had no side effects and in the remaining 62 patients side effects were mild and transient. Most reactions had been experienced with previous regimens, but tingling of the scalp (3 patients), 'muzzy head' m and bronchospasm (2) were new complaints. Only 29 (1 8 %) patients withdrew due to side effects. Manderson, W.S.: Practitioner 222: 131 (Jan 1979)

... and good single drug control is possible for the 'difficult' hypertensive patient Labetalol 300-600mg daily for 3 months gave good blood pressure control in 49 patients with hypertension resistant to other therapy. In 43 of the 49 patients labetalol was sufficient alone and in combination with pther drugs in the remaining 6 patients. This open study in 53 general practice patients showed only 3 who had to withdraw due to severe side effects. 35 patients had mild tolerable side effects similar to those of ~-adrenergic blocking agents. Harris, c.: Current Medical Research and Opinion 5: 618 (No 8, 1978)

8 INPHARMA 3 Feb 1979 0156-2703/79/0203-0008 $00.50/0 © AD IS Press