Monday, October 27, 2008

MORE BAD NEWS FOR BETA-BLOCKERS IN HYPERTENSION

When I was a medical student about 30 years ago, beta-blockers were "THE " drug for management of heart disease, including hypertension. The concept of receptor blocking drugs, "the key that can turn on the lock ", was a very important pharmacological concept. Beta-blockers were in fashion for the treatment of hypertension. In the 70's we were also beginning to understand the RAA System. Dr John Laragh taught us that beta-blockers were essentially anti-renin and so should be used for hypertensives with high renin. There were then many clinical trials of management of hypertension, many of them including the use of beta-blockers, especially atenolol.
Looking back now, we realise that although many of the trials show good BP control, non of the trials with the beta-blockers, found a reduction in mortality.
Of course in the new millenium, beta-blockers are now out of fashion. In fact, we believe that the use of beta-blockers in hypertension, may be associated with higher morbidity.
The Oct 28th issue of the Journal of the American College of Cardiology, carried an article by Dr Bangalore from New York, who did a meta-analysis of 9 clinicla trials involving 30,000 patients. They found that a lower heart rate was associated with increase risk of death and cardiovascular events. Since most of the trials involved the use of atenolol as the beta-blockers, some have concluded that the use of atenolol may be associated with greater CVS morbidity and mortality. Some dispute this conclusion. But I must say that, I do think that lowering the heart rate with beta-blockers may be associated with a higher central aortic pressure, and therefore a greater incidence of strokes and other CVS events.
Of course, it is good to remember that there are now so many types of beta-blockers. There are the classical beta-blockers, beta-blockers with alpha-blocking effects as well ( and so have some vaso-dilatory actions ), and there are beta-blockers that are just heart rate blockers. Therefore, I suppose it is hard to generalise that all beta-blockers are bad. We do know, however that atenolol is bad. BUT, atenolol is cheap, and so many GPs are using them as they give a higher profit margin. Newer anti-hypertensive agents are expensive ( read lower profit margins ).
However, it would be correct, in the light of present evidence, that atenolol and maybe also metoprolol and propranolol, should not be use for the management of hypertension, unless the patient also have concomitant CAD and angina. It maybe better to risk lower profit margin and follow evidence base medicine, and so better patient-care.

2 comments:

Dr. Shankhdhar said...

Beta Blockers are diabetogenic is quite established yet ignored fact. This is yet another reason to avoid beta blockers as initial therapy for management of hypertension

msforty5 said...

I'm reading your articles for info & your blog is truly informative. At a forum during World Heart Day last year, a cardiologist mentioned that menopausal women SHOULD never take statins etc if advised by gynae so as to protect the heart as there are new medical evidence linking it to heart disease just like HRT scare. Is it true? Thanks