Clonidine acts in the brain, inhibiting adrenergic outflow from the brainstem. Inhibition of sympathetic outflow results in a decrease in blood pressure.

Clonidine reduces cardiac output:

• (by reducing both stroke volume and heart rate) and peripheral resistance.

• Reduction in stoke volume occurs due to increased venous pooling (decreased preload).

Clonidine does not interfere with cardiovascular responses to exercise.

Renal blood flow and function is maintained during clonidine treatment.

Clonidine has minimal or no effect on plasma lipids.

Adverse Effects:

• Dry Mouth (xerostomia)

• Bradycardia (in patients with SA nodal abnormality)

• Withdrawal syndrome upon abrupt discontinuation (increased blood pressure, headache, tachycardia, apprehension, tremors)