How Do Beta1Beta2 Adrenergic Agonists Work?

Beta-1/Beta-2 adrenergic agonists are a class of drugs used for the management of heart failure. They work by simultaneously binding to both Beta-1 and Beta-2 adrenergic receptors. Beta-1 and Beta-2 adrenergic receptors are a type of adrenergic receptor that plays a central role in the sympathetic nervous system—the part of the nervous system that increases heart rate, blood pressure, breathing rate, and eye pupil size. Beta-1 is mainly present on the muscle tissue of the heart (myocardial tissue), whereas Beta-2 is present on the smooth muscle cells.

Beta1/Beta2 agonists bind simultaneously to both Beta-1 and Beta-2 adrenergic receptors and activate them. Activation of these receptors can lead to:

• Cardiac stimulation
• Dilation of the blood vessels
• Relaxation of the gastrointestinal tract
• Relaxation of uterine smooth muscle

Apart from these, stimulation of Beta-2 adrenergic receptors can lead to:

• Dilation of the airway in the lungs
• Release of a hormone called glucagon from the pancreas
• Breakdown of the molecule glycogen to glucose in the liver

Similarly, stimulation of Beta-2 adrenergic receptors results in:

• Stimulation of the kidney to release renin, which stimulates the production of a hormone angiotensin II and subsequent release of aldosterone from the adrenal gland

Beta1/Beta2 adrenergic agonists are mainly used to treat:

• Heart failure
• Shock
• Bronchospasm (muscles in the lung tighten causing restricted airflow) during anesthesia
• Peripheral vascular disorders (circulatory condition in which narrowed blood vessels reduce blood flow to the legs)

Some of the side effects of Beta1/Beta2 adrenergic agonists include:

• Dizziness
• Nausea
• Vomiting
• Palpitations
• Trembling
• Postural hypotension (drop in blood pressure upon standing)
• Chest pain
• Nervousness
• Restlessness
• Confusion
• Headache
• Weakness
• Blurred vision
• Shortness of breath
• Irregular heart rate

The information contained herein is not intended to cover all possible side effects, precautions, warnings, drug interactions, allergic reactions, or adverse effects. Check with your doctor or pharmacist to make sure these drugs do not cause any harm when you take them along with other medicines. Never stop taking your medication and never change your dose or frequency without consulting your doctor.

Drug names include:

• Isoproterenol (Isuprel)
• Nylidrin