Your Medication Atenolol Atenolol is also known as the brand name: Tenormin Atenolol comes in 25, 50, 100 mg tablet. Atenolol is most commonly used for high blood pressure, chest pain, and support after a heart attack. No matter what your doctor has you taking it for, atenolol is usually taken by mouth once daily and without regards to meals. Standard dosing of atenolol ranges from 25 mg to 100 mg daily Some common side effects with atenolol include low blood pressure, dizziness, chest pain, confusion, headache, constipation, diarrhea, nausea, and possible issues with fertility. Some less common side effects with atenolol include loss of hair, difficulty breathing, wheezing, and hallucinations. Do not take atenolol if: you are or may become pregnant While taking Atenolol, remember it is important to tell your doctor or pharmacist if you have: • Signs of an allergic reaction, such as rash, itching, or hives • A history of heart failure Do not abruptly stop taking this drug. The dose must gradually be lowered.