J. Harris,

Thanks for your question.

Atenolol is a drug known as a beta blocker and is used in the treatment of high blood pressure, coronary artery disease and various types of arrhythmias.  This drug has been in use for about 25 years and has a longer half life that prior beta blockers like inderal (propranolol).  It is usually taken once or twice a day and is well tolerated by patients. 

Atenolol works by slowing down the heart rate, as well as decreasing the force of each contraction of the heart.  Both of these actions result in less work done by the heart and a lower blood pressure.  Because there is less work done, less oxygen is needed and this helps if there are blockages in the coronary arteries which can cut the oxygen supplied to the heart muscle.  When the blood pressure is lower, this also reduces the pressure that the heart has to pump against, again making the workload of the heart easier. 

For arrhythmias, atenolol slows the electrical pathways down, which, as mentioned about, slows the heart beat.  This also delays the conduction of impulses through various nerve bundles (the natural pacemaker and the atrioventricular node) which can improve various abnormal rhythms.  Some people can be very sensitive to beta blockers and the heart can become too slow, causing problems like dizziness and even passing out.  Therefore close follow up is needed for patients beginning treatment with this drug. 

I hope this has been helpful.  Best wishes.

Martin Cane, M.D.