Drugs categorized beta-blockers are familiar among people with heart problem.
Many doctor using this prescribe for the patient due to improving heart-beat and amount of blood that pumped by heart organ, by blocking the neurotransmitter from binding to receptors.
The results, the heart-beat of patient will more relax.

As recent research published on May 31, 2008 by Lancet that these drugs will impact for increasing of strokes rate and mortality caused by blood loss due high doses of these drugs, also may linked to increasing risk of complication for anemia patient that need surgery.
This impact founded by W. Scott Beattie, MD, PhD, Fraser Elliot chair in Cardiac Anesthesia, University Health Network.
He said, “the natural response of the body to blood loss and the action beta blockers induce on the body create a paradox for treatment. Blocking the appropriate response of the body to anemia, as would happen with patients who are on or in need of beta blockers, may actually increase the risk of anemia-induced adverse cardiovascular events.”

Richard B, Weiskopf, MD, from the University of California, San Fransisco, accompanying editorial added, “until better data are available, while beta-adrenergic antagonists appear to protect the myocardium of high-risk patients, and may well be of lesser or no efficacy for patients at lesser risk, it would seem prudent to avoid those agents that substantially impair the cardiac response to acute sever anemia when that or substantial hemorrhage is anticipate.”

In this case showed that we should pay attention carefully that there is connection, risk and complicated impact between hemoglobin blood levels and beta blocker effects.