Wednesday, August 8, 2007

Beta Blockers in Uncomplicated Hypertension

New review "beats the drum" for not using beta blockers in uncomplicated

August 8, 2007

New York, NY - A new review published in the August 14, 2007 issue of the Journal of the American College of Cardiology further explores the use of beta blockers in uncomplicated hypertension, with experts arguing that doctors should stop prescribing the drugs as monotherapy or first-line agents in uncomplicated hypertension, as there is a lack of evidence to support their use

"Year after year, the use of beta blockers has been increasing in the United States," Dr Franz Messerli (St Luke's-Roosevelt Hospital, New York), one of the authors, told heartwire. "This is despite the fact that we showed many, many years ago, for hypertension, that there is basically no evidence for their use."

Messerli said that despite a number of meta-analyses showing no benefit of beta-blocker use in patients with hypertension the agents appear to have the "myth of cardioprotection attached to them." This myth, explained Messerli, originates from studies showing benefit in the post-MI patient. While beta blockers reduce reinfarction rates and even morbidity and mortality in these patients, the cardioprotection myth is erroneously extended to a number of different indications, most notably hypertension, all under the assumption that "what is good for the goose must be good for the gander," he said.

Beta blockers in hypertension

Speaking with heartwire, Messerli said that beta blockers, specifically atenolol, were the fourth-most-prescribed drug in the US and that, based on a report in the New York Times, there are more than 44 million prescriptions for the popular beta blocker yearly. Most of these prescriptions, said Messerli, are for hypertension, and many guidelines, including the US and European guidelines, still recommend the use of beta blockers as first-line therapy or as on an "equal footing" with thiazide diuretics, calcium antagonists, or renin angiotensin aldosterone system (RAAS) blockers. The most recent UK hypertension guidelines, however, have omitted beta blockers for routine use.

The purpose of the new review, explained Messerli, was to highlight the paucity of data supporting the use of beta blockers in uncomplicated hypertension and to "beat the drum among cardiologists to make them realize that what they are doing is no longer appropriate."

Since the Veterans Administration (VA) study in the 1970s, numerous studies have documented reductions in stroke, and to a lesser extent, MI and cardiovascular morbidity and mortality, in hypertensive patients treated with a diuretic-based antihypertensive therapy. However, after more than 30 years, no study of beta blockers has shown that their use as monotherapy reduces morbidity and mortality in hypertensive patients, said Messerli.

"What is the evidence for atenolol in hypertension?" asked Messerli. "Zero. Zilch. There has never been a study in hypertension with atenolol that has shown a reduction in heart attacks or strokes."

The most recent evidence, a meta-analysis previously reported by heartwire and cited by Messerli and lead author Dr Spiral Banagalore (St Luke's-Roosevelt Hospital, New York) in their review, recently showed beta blockers to be ineffective as first-line drugs in the treatment of hypertension.

The review, published in January, bases this conclusion on "the relatively weak effect of beta blockers to reduce stroke and the absence of an effect on coronary heart disease when compared with placebo or no treatment" and "the trend toward worse outcomes in comparison with calcium-channel blockers, renin-angiotensin-system inhibitors, and thiazide diuretics."

Different types of patients

Post-MI patients, in whom beta blockers are appropriately prescribed, differ from hypertensive patients in that they have severe manifest coronary artery disease, Messerli explained. In post-MI and congestive heart failure patients, beta blockers slow the heart rate and shield the heart from surges in catecholamines, physiological effects beneficial to patients with coronary disease.

Uncomplicated hypertensive patients, on the other hand, particularly the elderly, are characterized by low cardiac output, low heart rate, and very high peripheral resistance, and prescribing beta blockers in this setting "accelerates the biological clock, said Messerli. Heart rate slows further, cardiac output decreases, and peripheral resistance increases, and for this reason, beta blockers should not be prescribed in uncomplicated hypertension.

Messerli concludes that the risk/benefit ratio of beta blockers does not make them an option for the treatment of uncomplicated hypertension. "Hypertension," he said, "is an asymptomatic disease, and our treatment for it should also remain asymptomatic." Given the increased risk of stroke, the failure to lower central aortic pressure, and numerous adverse effects, including predisposing patients to diabetes mellitus, drowsiness, and lethargy, as well as peripheral vascular and pulmonary side effects, the risk/benefit ratio for beta blockers is "not acceptable for this indication.

Bangalore S, Messerli FH, Kostis JB, Pepine CJ. Cardiovascular protection using beta blockers. J Am Coll Cardiol 2007; 50:563-72.

Wiysonge CS, Bradley H, Mayosi BM, et al. Beta blockers for hypertension. Cochrane Database Review 2007;1: CD002003

Related links:

Cochrane review: Beta blockers should not be first line for hypertension
HeartWire News; Feb 02, 2007

New UK hypertension guidelines omit beta blockers for routine use HeartWire News; Jul 06, 2006

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