Since many of the conditions that beta blockers treat are chronic, you may have to take this medicine for the rest of your life. Side Effects and Risks Common side effects include slowed heartbeat, tiredness, nausea, diarrhea, constipation, and decreased sexual ability. Other mild side effects can include difficulty sleeping or nightmares, headache, drowsiness, and numbness or tingling of the fingers, toes or scalp. Also, if you have diabetes, beta blockers can obscure some of the signs of low blood sugar, such as tremors or rapid heartbeat. Check with your doctor if any of these side effects seems troublesome or if you have any questions.
More serious reactions can sometimes occur with beta blockers.
Because beta blockers can trigger or worsen these conditions, make sure your doctor knows about them. If any of these or other serious reactions occur, call your doctor immediately. If you suddenly stop taking a beta blocker, you could worsen your condition and experience potentially dangerous side effects, such as chest pain, fast or irregular heartbeat, high blood pressure, and headaches. Always check with your doctor before discontinuing a beta blocker. Consult with your doctor if you think you could become pregnant or plan to breast-feed while on a beta blocker.