Side Effects

• Atenolol may cause side effects in some patients. Some of the less serious side effects may include a decreased libido, difficulty having an orgasm, impotence, sleep problems such as insomnia, fatigue, anxiety and nervousness. Talk to your doctor about switching to another medication if any of these side effects become troublesome to you.
  
  

Serious Side Effects

• If you experience more serious side effects, contact your doctor immediately. These may include a cold feeling in your extremities, swelling of the ankles or feet, depression, stomach pain, nausea, jaundice, loss of appetite, fever, clay-colored stools, dark urine, uneven or slow heartbeat, lightheadedness, fainting and feeling short of breath. In addition, if you experience an allergic reaction, go to the emergency room at once. Symptoms of an allergic reaction may include problems breathing, hives and facial swelling.
  
  

Overdose

• Possible signs of an overdose of atenolol may include seizures, fainting, weakness, dizziness, bluish fingernails, shortness of breath and uneven heartbeats. To avoid an overdose, carefully follow your doctor's dosing instructions and never take more than the prescribed dose.
  
  

Interactions

• Tell your doctor about all of your other medications, whether they are prescription, non-prescription or over-the-counter supplements. Some other drugs may interact with atenolol. These may include cold medications, stimulants, diet pills, medications for asthma or any other breathing disorder, any heart medications, an MAO inhibitor, diabetes medications (including insulin), guanabenz, digoxin, disopyramide, clonidine, amiodarone or any allergy treatments (including if you are currently undergoing skin testing).
  
  

Pre-existing Conditions

• Never use atenolol if you are allergic to it. Some other pre-existing medical conditions may preclude you from using this drug, or you may need an adjusted dose. These conditions may include diabetes, low blood pressure, asthma, emphysema, bronchitis, other breathing disorders, depression, a heart condition (slow heart rate, congestive heart failure or a heart block), a thyroid disorder, kidney or liver disease, any problems with circulation, pheochromocytoma, myasthenia gravis or depression. Never use atenolol if you are pregnant or breastfeeding. Atenolol can cause birth defects and may also harm a nursing infant. If you become pregnant while using this drug, tell your doctor immediately.