The efficacy and safety of the recommended intramuscular (im) clinical doses of xylazine-ketamine (5mg-35mg/kg), diazepam-ketamine (5mg-60mg/kg) and acepromazine-ketamine (5mg-75mg/kg) post administration were obtained, evaluated and compared using the following parameters in 10 apparently healthy rabbits: vital parameters (means of heart rates, respiratory rates and temperature), onset of loss of righting reflex, onset of analgesia, duration of analgesia, duration at recumbency and attempts to stand. Onset of loss of righting reflex was not significantly different (p>0.05) with xylazine-ketamine, diazepam-ketamine and acepromazine-ketamine at 3.4±0.3, 2.0±0.0 and 2.6±0.3 minutes respectively. Diazepam-ketamine and acepromazine-ketamine showed no analgesia while xylazine-ketamine had onset of analgesia and duration of analgesia of 4.2±0.1 and 57.0±0.7 minutes respectively. Duration of recumbency and first attempt to stand were longest with diazepam-ketamine, intermediate with acepromazine-ketamine and shortest with xylazine-ketamine of 184.4±3.3 and 42.0±1.4; 169.9±3.0 and 26.6±1.7; and 62±1.5 and 11.2±0.9 minutes respectively. Mean heart rate ranged between 173.2±6.6 to 187.2±7.5; 188.6±6.4 to 206.0±3.1 and 190.8±1.3 to 202.8±1.9 beats/minute with xylazine-ketamine, diazepam-ketamine, and acepromazine-ketamine respectively. Mean respiratory rate ranges were 58.4±3.5 to 133.0±11.2; 71.4±6.9 to 121.2±12.6 and 80.8±6.2 to 137.0±4.3 breaths/minute with xylazine-ketamine, diazepamketamine and acepromazine-ketamine respectively. Mean temperature ranges were 39.9±0.1 to 40.0±0.1; 39.0±0.3 to 39.9±0.1 and 39.6±0.1 to 40.2±0.0 : C with xylazine-ketamine, diazepam-ketamine and acepromazineketamine respectively. In conclusion, all the three ketamine drug combinations produced unconsciousness and immobility, but only xylazine-ketamine provided additional analgesia. They were associated with normal heart rate and rectal temperature, as well as polypnoea of some clinical concern. Only xylazine-ketamine is potentially useful for painful procedures. Addition of specific analgesics to diazepam-ketamine and acepromazine-ketamine may make them useful for painful procedures.

The effect of ascorbic acid premedication on dexmedetomidine-ketamine anaesthesia was evaluated in five cats in two sets of experiments namely dexmedetomidine-ketamine (control) and ascorbic acid /dexmedetomidine/ketamine (test). The control group involved concurrent intramuscular administration of 10 mg/kg ketamine and 10 µg/kg dexmedetomidine to each cat. Selected anaesthetic indices and vital parameters were recorded at ten minutes' interval for a period of 90 minutes using standard methods. A week later, the test experiment was conducted with the same cats used in the control experiment but the trial was preceded with intramuscular injection of 20 mg/kg ascorbic acid 10 minutes before the concurrent administration of the previously used doses of dexmedetomidine and ketamine. Vitamin C premedication did not produce any significant difference on heart and respiratory rates and rectal temperature of the treated cats. Onset of drug action was not influenced by premedication with vitamin C and was the same in both control and test groups (3.6 ± 1.50 min). The duration of analgesia was also similar for both control (45.6 ± 13.22 min) and test trials (44.4 ± 10.01 min). Ascorbic acid premedication produced a longer duration of anaesthesia (68.2±17.96 min) than the control (59.6 ± 21.51 min). It also produced a significantly (P < 0.05) shorter time to stand (2.2 ± 2.49 min) than the control (4.8 ± 5.34 min). It was concluded that vitamin C intramuscular administration at a dosage of 20mg/kg prior to dexmedetomidine-ketamine anesthesia in cats produced a longer duration of anaesthesia but hastened the time to stand from sternal recumbency.