p-Biockers Reduce Stress-Induced Increases in Cardiac Workload Metoprolol and propranolol are more effective than hydrochlorothiazide in hypertensives

To compare the effects of metoprolol with propranolol and hydrochlorothiazide in patients with essential hypertension, (WHO stage 1-11), undergoing mental and physical stress, 47 patients randomly received metoprolol 100-400 (mean 243) mgjday (n = 15), propranolol 80-160mg bid (14) or hydrochlorothiazide 25-100 mg/day (16) for> 6 months. The haemodynamic effects of mental and physical stress were recorded during a colour word test, an orthostatic test and a cold pressor test before and after the active treatment periods.

Two patients were excluded because of poor compliance. Mean supine BP was reduced (p < 0.001) by each drug (n = 45) in the outpatient clinic and by metoprolol and propranolol in the laboratory (p < 0.001 ). Absolute BP levels during mental stress were significantly reduced in patients on {j-blockers, compared with those receiving hydrochlorothiazide without significantly affecting the stress-induced increase (30%) in BP in any treatment group. The induced rise in standing systolic BP was attenuated by each drug and diastolic BP by metoprolol and propranolol.

Mean resting supine HR was reduced (p < 0.001) after treatment with metoprolol and propranolol but not after hydrochlorothiazide. The mental stress-induced increase in HR was, however, attenuated in each treatment group. The mean rate pressure product fell by 44 and 42% (p < 0.001) during mental stress after metoprolol and propranolol, respectively, and by 15% (p < 0.05) after hydrochlorothiazide (p < 0.001 between (j-blockers and hydrochlorothiazide both during mental stress and at rest). Self assessment of stress (by visual analogue scales) was not significantly altered after any of the treatments. Patients on metoprolol and propranolol rated increased levels of tiredness (p < 0.05) at rest, but not after mental stress.

Changes in plasma epinephrine [adrenaline] and norepinephrine [noradrenaline] levels were not correlated w1th haemodynamic responses.

Thus, blood pressure levels and cardiac workload were reduced more effectively by metoprolol and propranolol than by hydrochlorothiazide, in hypertensive patients at rest and under stress, but none of the treatment regimens appeared to alter the relative haemodynamic responsiveness of these patients to stress. Eliasson K, Kahan T, Hylander B. HJemdahl P British Journal of Clinical Pharmacology 24: 1-14, Jul 1987

0156-2703!87 /1017-0015/0$01.00/0 © ADIS Press INPHARMA" 17 October 1987 15