Beta blockers are medications widely prescribed to treat high blood pressure, angina pectoris, arrhythmias, congestive heart failure and also for the prevention of migraines. According to IMS Health, beta blockers ranked fifth among the top 15 classes of drugs dispensed by prescription in 2008, accounting for nearly 160 million prescriptions. Patients who take beta blockers should never stop taking these drugs abruptly, because the withdrawal symptoms can be severe and even life threatening.
How They Work
Also known as beta-adrenergic blocking agents, beta blockers work by blocking epinephrine (adrenalin) and norepinephrine from binding to beta receptors on nerve cells. Of the three types of beta receptors, beta blockers are most effective on Beta-1 and Beta-2 receptors. The former are located in the nerve cells of the heart, eyes and kidneys, while the latter are found in cells of the blood vessels, lungs, liver, digestive tract, uterus and musculoskeletal system. Popular beta blockers include carvedilol (Coreg), acebutolol (Sectral), propranolol (Inderal LA), bisoprolol (Zebeta), metoprolol (Lopressor, Toprol XL), atenolol (Tenormin), nadolol (Corgard) and nebivolol (Bystolic).
Cardiovascular Disease Patients
Abrupt withdrawal of beta blockers usually results in a sharp but temporary upsurge in adrenergic activity, which is set in motion by the binding of epinephrine or related substances to the nerve cells. For patients with cardiovascular disease, this may cause a worsening of angina symptoms, heart attack, stroke and even death.
Patients with high blood pressure who abruptly withdraw from beta blockers may experience a variety of symptoms, including sinus tachycardia (a rapid heartbeat originating in the sinoatrial, or sinus, node of the heart), a dangerously sharp increase in blood pressure, palpitations, malaise and increased perspiration.
Incidence and Duration
Symptoms of beta blocker withdrawal are seen in about 5 per cent of the general population taking the drug but up to 50 per cent of those with angina, according to a fact sheet released by the University of Colorado Hospital Pharmacy. The duration of withdrawal symptoms is likely to be longer when the beta blocker withdrawn is of the short-acting variety, such as propranolol, rather than longer-acting drugs, such as nadolol.
It is unwise to self-medicate and equally unwise to stop taking a prescribed medication without first consulting with your doctor. Beta blockers are not the only drugs from which abrupt withdrawal may cause unwelcome symptoms. The University of Colorado Hospital Pharmacy recommends that patients be weaned off beta blockers over a period of 10 to 14 days to prevent acute withdrawal symptoms.