How Do Alpha-1 Agonists Work?

Alpha1 agonists are a class of medications that work by binding to the alpha1 adrenergic receptors. Alpha1 adrenergic receptors are a type of adrenergic receptors that play 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. Alpha1 adrenergic receptors are mainly present in the smooth muscles of the blood vessels and the muscle tissues of the heart (myocardial tissue). When these receptors are activated, they cause the blood vessels to constrict.

Alpha-1 agonists bind to the alpha1 adrenergic receptors and activate them. Activation of alpha1 adrenergic receptors can lead to:

• Increased resistance to the blood flow
• Increased workload on the heart
• Increased blood pressure
• Reduced cardiac output

Thus, alpha-1 agonists are mainly indicated for a condition like severe hypotension.

Alpha-1 agonists are administered intravenously or orally. Besides, they are marketed as topical applications administered in the eyes and nose as drops. Alpha-1 agonists are mainly used to treat hypotension. Other conditions include:

• Glaucoma (increased intraocular pressure)
• Septic shock (widespread infection that causes organ failure and dangerously low blood pressure)
• Cardiac arrest
• Nasal congestion

Some of the side effects of alpha-1 agonists include:

• Goosebumps
• Increased blood pressure while sleeping
• Tingling sensation
• Difficulty in urinating
• Itching
• Chills
• Rash
• Abdominal pain
• Anxiety
• Confusion
• Dizziness
• Dry skin
• Redness on face
• Headache
• Insomnia
• Nausea
• Weakness
• Leaking from the site of injection
• Sneezing
• Metabolic acidosis (increased buildup of acid in the blood or urine)
• Irritation in the stomach

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.

Generic and brand names of alpha-1 agonist drugs include:

• Phenylephrine (Vazculep, Biorphen)
• Midodrine (ProAmatine, Orvaten)