PURPOSE OF REVIEW: Since its introduction in 1966, clonidine, an α(2) adrenergic receptor agonist, has been widely used in clinical practice as an antihypertensive, nasal decongestant, ADHD medication, sedative, and analgesic. When α(2) adrenergic receptors are stimulated, sympathetic outflow is decreased. This leads to reduced norepinephrine release from the presynaptic neuron, which modifies pain through the dorsal horn and induces sedation through the locus coeruleus.
