Take atenolol exactly as it was prescribed for you. Do not take the medication in larger amounts or for longer than recommended by your doctor. Take this medication with a full glass of water. Take atenolol at the same time every day.

Atenolol is in a group of drugs called beta-blockers. Beta-blockers affect the heart and circulation (blood flow through arteries and veins).

Call your doctor at once if you have any of these serious side effects: slow or uneven heartbeats; feeling light-headed, fainting; feeling short of breath, even with mild exertion; swelling of your ankles or feet; nausea, stomach pain, low fever, loss of appetite, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes); depression; or cold feeling in your hands and feet.

To be sure this medication is helping your condition, your blood pressure will need to be checked on a regular basis. It is important that you not miss any scheduled visits to your doctor. If you need to have any type of surgery, tell the surgeon that you are using atenolol. You may need to briefly stop using atenolol before having surgery. Atenolol is only part of a complete program of treatment for hypertension that may also include diet, exercise, and weight control. Follow your diet, medication, and exercise routines very closely if you are being treated for hypertension. Hypertension often has no symptoms, so you may not even feel that you have high blood pressure. Continue using this medicine as directed, even if you feel well. You may need to use blood pressure medication for the rest of your life.