Atenolol belongs to general class of cardiac drug that is used in veterinary medicine and is indicated in treating certain heart diseases like arrythmias. During the course, the medicine controls the heart rate, lowers blood pressure and deals with rhythm irregularity in animals like cats, dogs and ferrets. In certain cases, the medication is also used in cats suffering from enlarged hearts. Atenolol, the active ingredient in the medicine is a beta-blocker, which effectively deals with certain conditions affecting the heart. When administered, this oral medication helps in controlling abnormalities in the heart as well as in the blood pressure by blocking certain nervous system impulses. The medicine is available by prescription in capsule form.