Description

Clonidine is a centrally acting alpha-2 adrenergic agonist. It is typically available as an oral tablet or a transdermal patch.

Indication

• Hypertension (High Blood Pressure): Clonidine is most commonly prescribed to treat high blood pressure.
• ADHD (Attention-Deficit/Hyperactivity Disorder): It can be used off-label or as an adjunct therapy for some individuals with ADHD.
• Withdrawal Symptoms: It is sometimes used to manage withdrawal symptoms from opioids, alcohol, or nicotine.
• Vasomotor Symptoms: It can be used to treat hot flashes in menopausal women.
• Other uses: Can also be used to treat certain types of pain and Tourette’s syndrome.

Mechanism of Action

Clonidine works by stimulating alpha-2 adrenergic receptors in the brain, particularly in the brainstem’s vasomotor center. This stimulation has two main effects:

1. Reduced Sympathetic Outflow: It decreases the release of norepinephrine (a vasoconstrictor) from sympathetic nerves.
2. Decreased Heart Rate and Blood Pressure: By reducing sympathetic activity, it leads to a decrease in heart rate and a relaxation of blood vessels, which in turn lowers blood pressure.

This central action results in a reduction of peripheral resistance, a decrease in renal vascular resistance, and a decrease in heart rate, all contributing to a lower blood pressure.