Cardioselective vs. Non-Cardioselective Beta Blockers: Understanding the Difference

Beta-blockers treat hypertension (high blood pressure) by blocking the effects of adrenaline on the beta receptors of the heart. Cardioselective and non-cardioselective beta-blockers have the same functions, but work on different beta receptors.

Beta Receptors

• Beta-1 adrenoceptors control your heart rate and the force of the heartbeat, according to Dr. Richard E. Klabunde, author of "Cardiovascular Pharmacology Concepts." Beta-2 adrenoceptors control the relaxation of smooth muscle. Both types of beta receptors affect blood pressure levels.

Function

• Cardioselective beta-blockers only work on beta-1 adrenoceptors. Non-cardioselective adrenoceptors work on both beta-1 and beta-2 adrenoceptors. Both types of drugs slow the speed of nerve impulse transmission in the heart muscle.

Effects

• When the nerve impulses in the heart slow down, the heart needs less blood and oxygen to work properly. This reduces heart rate and makes it easier for the heart to supply other organs with blood.

Drugs

• Atenolol, acebutolol, bisoprolol, betaxolol, esmolol and bisoprolol work on beta-1 adrenoreceptors, making them cardioselective. Nadolol, timolol, labetalol, pindolol, propranolol, penbutolol and carvedilol work on both types of receptors, making them non-cardioselective.

Risks

• Common beta-blocker side effects include drowsiness, weakness, dry mouth, cold hands and feet, fatigue, shortness of breath, insomnia and dizziness, according to the Texas Heart Institute. Potential interactions exist between beta-blockers and medications that treat diabetes, depression, allergies and asthma.