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Wednesday, May 22, 2013
High Blood Pressure
Reducing heart rate in hypertensives harmful
I came across some studies mentioning that contrary to what was thought in the past ,reducing heart rate in hypertensives with beta blockers is actually very harmful. Beta blockers are already implicated in causing people to tip over to becoming diabetic and unsafe for asthmatics.
Is nebivolol safer and is it safe for asthmatics? Does it tip people into the diabetic range? Is nebivol effective for white coat effect and labile hypertension?
In general, lowering the heart rate is beneficial. A lower resting heart rate is associated with a lower mortality risk. This effect is small but consistent.
However, it appears to matter how heart rate is lowered. A recent review of 9 studies in hypertensive patients showed that beta blockers, when reducing the heart rate, increase mortality risk when compared to other modes of antihypertensive therapy. With one exception, the beta blocker in question was atenolol, and there is no good evidence that other beta blocker would have the same effect. It is also important to remember that many older studies have shown a clear benefit of beta blockers compared to no treatment. In patients with heart failure or coronary heart disease, beta blockers are very beneficial and should be part of the management.
Several experts now caution against the use of atenolol in the treatment of hypertension.
Nebivolol is a newer type of beta blocker. It has been used in Europe for over 11 years, and has been approved for the treatment of hypertension in the U.S. about one year ago. It has a better side effect profile and different effects on cardiac output and vascular resistance. It is difficult to compare it to atenolol. At this point, beta blockers , incl. nebivolol, can be considered safe and appropriate therapy for hypertension.
Beta blockers can be especially useful in patients who are somewhat anxious, and they may have an advantage in patients with white coat hypertension. There are no conclusive data to prove that point, however.
It is true that beta blockers cause a slight increase in the risk of developing diabetes, and they may slow the response to low blow blood sugar levels in diabetics. These effects are small, and have to be weighed against the benefit of beta blockers, esp. in patients with heart disease.
Max C Reif, MD
Professor of Medicine
Director of Hypertension Section
College of Medicine
University of Cincinnati