Side Effects of Propranolol

Propranolol is a medication in a class of drugs known as beta blockers 12. Beta blockers work by decreasing the contractility of the heart and dilating the blood vessels. Propranolol is used to treat tremors, angina, high blood pressure, heart rhythm disorders and other heart or circulatory conditions 12. Your doctor might also prescribe it to reduce the risk of heart attack and for the treatment of chronic migraine headache. There are some side effects associated with propranolol 12.

Is This an Emergency?

If you are experiencing serious medical symptoms, seek emergency treatment immediately.


While taking propranolol, you may experience fatigue that may lessen over time as your body adjusts to the drug 12. You should use caution while driving or completing dangerous tasks until you know how this medication will affect you. Getting at least 7 to 8 hours of sleep nightly and taking a midday nap may help lessen daytime fatigue. If you experience severe fatigue report it to your physician, who may recommend a change in medication or dosage.

Stomach Discomfort

Stomach discomfort may occur when taking propranolol 12. Symptoms can include nausea, vomiting, diarrhea, constipation and stomach cramps. You can take propranolol with food or milk if immediate stomach upset occurs 12. Small dietary changes, such as avoiding spicy foods and eating smaller meals throughout the day, may help alleviate stomach discomfort. If you develop severe or persistent vomiting or diarrhea, you may be at risk for dehydration and should consult your doctor.

Sexual Dysfunction

Propranolol may lead to sexual dysfunction in some patients 12. Side effects may include decreased sex drive, impotence or difficulty achieving orgasm. These side effects may diminish over time as your body gets used to daily treatment with propranolol 12. Notify your doctor if these effects become bothersome. He can recommend a change in medication or dosage, or prescribe a medication intended to treat sexual dysfunction.


Patients taking propranolol may develop insomnia, which is a difficulty falling and remaining asleep at night 12. This is thought to occur because beta blocker medications decrease the body's production of melatonin, which is the natural hormone in the body that helps to induce sleep. If you experience insomnia, consult your doctor.