How Do Adrenergic Agonists Work?

Adrenergic agonists are drugs that work by mimicking the functioning of the sympathetic nervous system—the part of the nervous system that increases heart rate, blood pressure, breathing rate, and eye pupil size.

The sympathetic nervous system causes the release of chemical messengers, such as noradrenaline and adrenaline from the adrenal glands. The primary function of adrenaline and noradrenaline is to constrict the blood vessels (vasoconstriction), which in turn:

• Increases blood pressure
• Accelerates the rate and force of contractions of the heart
• Opens the airways leading to the lungs
• Stops bleeding
• Increases the pupil size

As adrenergic agonist drugs are similar in structure to the chemical messengers, they mimic the actions of the chemical messengers. These drugs may also stimulate the release of adrenaline or noradrenaline.

As adrenergic agonist drugs mimic the action of adrenaline and noradrenaline, they are mainly used to treat:

• Bronchial asthma
• Shock
• Cardiac arrest
• Conjunctival congestion (pink eye)
• Nasal congestion
• Emphysema (lung condition leading to shortness of breath)
• Bronchitis

Some of the side effects of adrenergic agonist drugs include:

• Headache
• Tremor
• Irritation/burning in the eye
• Blurred vision
• Hypertension
• Tachycardia (irregular heartbeat)
• Palpitation
• Dry mouth
• Sedation
• Anxiety

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:

• Rohto Arctic
• Tetrahydrozoline, ophthalmic
• Visine Advanced Relief
• Visine Maximum Redness Relief
• Visine Original