Ketamine Infusions for Pediatric Sedation and Analgesia

Marcia L. Buck, PharmD, FCCP, FPPAG


Pediatr Pharm. 2016;22(6) 

In This Article

Mechanism of Action

Ketamine is a rapid-acting general anesthetic with analgesic properties. It has multiple binding sites, including N-methyl-D-aspartate (NMDA), opioid, nicotinic, and muscarinic cholinergic receptors. Its primary mechanism of action is thought to be noncompetitive NMDA antagonism, blocking the effects of glutamine. While depression of the thalamocortical system at lower ketamine concentrations produces a dissociative state, administration of larger doses or continuous administration to achieve higher drug levels results in a much deeper level of sedation due to suppression of the reticular-activating and limbic systems.[1–3]

Ketamine offers several advantages over other sedative/analgesics. In most patients, administration of ketamine results in only minimal respiratory depression with preserved or exaggerated pharyngeal and laryngeal reflexes, normal or slightly increased muscle tone, and relatively minor elevations in blood pressure, heart rate, and cardiac output. The cardiac effects associated with ketamine result from blockade of catecholamine reuptake, producing a sympathomimetic effect. Changes typically occur shortly after injection and reach a maximum within minutes. In most patients, systolic and diastolic blood pressures peak at 10% to 50% above pre-anesthetic levels and return to baseline within 15 minutes after drug administration is completed.[1–3]