Background

Sublingual benzodiazepines, including midazolam, are effective in humans. Ketamine also has sublingual absorption in human. The current study compared acceptance of and behavioral responses to Transmucosal midazolam and Ketamine administered via the sublingual route in cat.

Methods

Ten mal mature free roaming cats received different doses of Ketamine (20, 40, 80, 120 mg/kg) Or midazolam (0.3, 0.6, 1.2, 2.4, 4.8 mg/kg) under the tongue with additional sugar. Each animal was observed continuously by a winded observer for CNS depression as graded on the behavioral scale shown in under. Our scales for CNS depression were: 1) no effect 2) impaired gait, prancing gait, some excitement 3) lowered head, braced stance, hindquarter weakness 4) sternal or lateral recumbency, some responsiveness to repositioning, unable to stand 5) lateral recumbency, no response to movement of limbs, no reaction to pain. Quantal data were obtained by determining the percentage of animals which lost the reflexes (above scores) for each dose. Peak scores for each dose and the percentage of animals that reached each peak score is given.

Results

Animals accepted midazolam and Ketamine administered via the sublingual. Different doses of ketamine and midazolam showed dose dependent effect in CNS depression. Midazolam administration via the sublingual in 1.2, 2.4, 4.8 mg/kg doses could induce only immobility (score = 4) in 100% of animals but all of cats in any doses react to pain. 100% of animals showed no reaction to pain (score = 5) in ketamine (80, 120 mg/kg). Also onset of effect in midazolam administration was dose dependent but in regard with ketamine wasn't in this order.

Conclusion

Sublingual administration of ketamine is effective as and better suppressed than sublingual midazolam as a sedative-hypnotic in cats. Our findings suggest that the ketamine subligual administration should be selected for anesthetic effects in cat.