Behavioural and Toxic Interaction Profile of Ketamine in Combination with Caffeine

Abstract: Ketamine street tablets often contain several other compounds in addition to ketamine, among them is caffeine. The purpose of this study was to examine whether caffeine interacts with ketamine‐induced behavioural and toxic effects. Male ICR mice were treated with ketamine alone or ketamine combined with various doses of caffeine, then the locomotor activity, rotarod test, prepulse inhibition of acoustic startle, loss of righting reflex, and mortality rate were examined. Caffeine enhanced the locomotor hyperactivity, caused disruption of the rotarod performance, and mortality rates due to ketamine, whereas prepulse inhibition deficits and anaesthesia remained unaffected. These findings demonstrate that use of ketamine in combination with caffeine enhances its stimulant responses and lethal risk, suggesting that a potentially toxic interaction exists between ketamine and caffeine.