Individuals may not take atenolol like a vitamin to prevent dangerously low heart rates. Atenolol is a prescription medication that lowers blood pressure and decreases heart rate, as explained by MedlinePlus. Patients should take this medication exactly as directed by their doctors.
Atenolol is a beta blocker, as noted by MedlinePlus. This medication increases blood flow and lowers blood pressure by relaxing blood vessels and decreasing heart rate. Common side effects of atenolol include dizziness, lightheadedness, fatigue, depression and diarrhea. Serious side effects, including difficulty breathing, weight gain, fainting and swelling of the arms or legs, require prompt medical care.