Side Effects

• Common side effects include dizziness, tiredness, slow heart rate, drowsiness, depression, nausea, diarrhea, swelling of the ankles and feet, and decreased sex drive.
  
  

Contraindications

• Inform your doctor before taking this medication if you have a slow heart rate, heart block or allergies. Also tell your doctor if you are pregnant or have other health problems such as diabetes, psychiatric illness or heart failure.
  
  

Overdose

• Severe side effects can come from an overdose of this medication. Symptoms include decreased breathing, very low blood pressure and heart rate, and heart failure. Call your doctor immediately if you notice any of these side effects.
  
  

Pregnancy

• Atenolol should not be used while pregnant or breastfeeding. The medicine enters the umbilical cord blood and can cause low birth weight babies. It is passed through breast milk and can cause low blood sugar and heart rates in infants.
  
  

Duration

• Atenolol usually exits your system within 24 to 48 hours.