Clinical Efficacy and Risks of Clonidine Infusion for Sedation and Analgesia: A Narrative Review

Since its introduction in 1966, clonidine, an α₂ adrenergic receptor agonist, has been widely used in clinical practice as an antihypertensive, nasal decongestant, ADHD medication, sedative, and analgesic. When α₂ 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.

Clonidine preparations have been utilized for various purposes in anesthesia over the past few decades. In this regard, infusions can be used perioperatively as a sedative and analgesic, a one-time bolus, or a continuous infusion. Clonidine infusion reduces opioid requirements and can be used to treat both nociceptive and neuropathic pain after surgical procedures. There is a lack of research on isolated efficacy and risk for sedation related to prominent use as adjunctive therapy. Future research is warranted to investigate clonidine unaccompanied to determine performance and potential. Furthermore, there is a gap in our literature between the efficacy, risk, and side effects of continuous clonidine compared to non-continuous clonidine for analgesia. This narrative review aims to highlight the current state of knowledge of clonidine's pharmacology, indications, efficacy, sedative properties, analgesic ability, and side effects.