Ketamine can show large inter-individual variation in effect, and therefore dose rates administered should be tailored to the individual animal, dependant on factors such as age, condition, and the depth and duration of anaesthesia required. Prolongation of effect is possible by repeated administration of an optionally reduced initial dose.
Administration is possible intravenously (horse and cattle), intramuscularly (pig, dog and cat) or in cats also subcutaneously.
In adult farm animals intravenous application is recommended.
For combination use: before ketamine is administered, please ensure that the animals are adequately sedated.
HORSE
Pre-medication with a sedative is required for a sufficient anaesthetic effect:
To induce anaesthesia
With detomidine:
Detomidine 20 μg/kg IV,
after 5 minutes
Ketamine 2.2 mg/kg fast IV (2.2 ml/100 kg)
Onset of action is gradual, taking approximately 1 minute to attain recumbency, with duration of anaesthetic effect lasting approximately 10 - 15 minutes.
With xylazine:
Xylazine 1.1 mg/kg IV, followed by
Ketamine 2.2 mg/kg IV (2.2 ml/100 kg)
Onset of action is gradual, taking approximately 1 minute, with duration of anaesthetic effect being variable and lasting 10 - 30 minutes but usually less than 20 minutes.
After injection the horse lays down spontaneously without any further help. If a distinct muscle relaxation is required simultaneously, muscle relaxants can be administered to the recumbent animal, until the horse shows first symptoms of relaxation.
CATTLE
To avoid uncontrolled lying down and possible symptoms of excitation or for potentiation of anaesthesia a sedative premedication is recommended. To avoid hypoxia due to lateral or dorsal recumbency, oxygen can be administered through a nasal tube.
To induce anaesthesia
With xylazine
Xylazine 0.14 - 0.22 mg/kg IV/IM, followed by
Ketamine 2 - 5 mg/kg IV (2 - 5 ml/100 kg)
Onset of action is approximately 1 minute, with duration of anaesthetic effect lasting approximately 30 minutes.
The lower end of the stated dose range should be used when administering xylazine via the intravenous route.
PIG
To induce anaesthesia
With azaperone
Ketamine 15 - 20 mg/kg IM (1.5 - 2 ml/10 kg)
and 2 mg/kg azaperone IM.
In 4 – 5 month old pigs, following administration of 2 mg/kg azaperone and 20 mg/kg ketamine IM the onset of anaesthesia took on average 29 minutes and duration of effect lasted about 27 minutes.
DOG
Ketamine can not be used as a mono-anaesthetic in dogs, as it causes an increased muscle tone and uncoordinated muscle contractions.
To induce anaesthesia
With medetomidine
Medetomidine 40 μg/kg IM, followed by
Ketamine 5 - 7.5 mg/kg IM (0.5 - 0.75 ml/10 kg)
Duration of effect varies between 30 - 50 minutes and is dose related.
With xylazine
Xylazine 2 mg/kg IM, after 10 minutes
Ketamine 10 mg/kg IM (1 ml/10 kg).
In dogs weighing more than 25 kg bodyweight reduce xylazine dosage to 1.3 mg/kg.
Onset of action is usually within 10 minutes and duration of effect lasts for approximately 30 minutes.
With diazepam
Administer diazepam 0.25 mg/kg IV, immediately followed by Ketamine 5 mg/kg IV (0.5 ml/10 kg). Ketamine should be injected slowly and generally administered to effect, when used intravenously. Appropriate premedication should be used to ensure adequate sedation before administration of the diazepam-ketamine combination and to facilitate intubation. The optimal dosing regimen should be individually based on the pre-medication used. Average duration of effect is 10-20 minutes.
CAT
Mono-anaesthetic use of ketamine is possible, but to avoid undesired psychomotoric effects combined anaesthesia is recommended. Ketamine on its own may be used by intravenous injection, but intramuscular injection is the recommended route. Ketamine should be injected slowly when administered intravenously.
As a sole agent
11 mg/kg ketamine IM for minor restraint,
22 - 33 mg/kg ketamine IM for minor surgery and restraint of fractious cats.
Duration of ketamine anaesthesia is 20 – 40 minutes and recovery takes place over a 1 – 4 hour period. .
To induce anaesthesia (anaesthesia < 1 hour)
With medetomidine
Medetomidine 80 μg/kg IM, followed by
Ketamine 5 – 7.5 mg/kg IM (0.25 - 0.4 ml/5 kg)
Onset of action is usually 3 - 4 minutes and duration of effect varies between 30 - 60 minutes and is dose related.
With xylazine
Xylazine 1 - 2 mg/kg IM/SC and
Ketamine 10 - 20 mg/kg IM/SC (0.5 - 1 ml/5 kg)
The lowest dose of xylazine (1 mg/kg) should be used, if ketamine is used at the highest dose (20 mg/kg).
Onset of action is usually within 5 minutes of ketamine administration and duration of effect lasts for at least 30 minutes.
Due to low dose volumes, it is recommended to use an insulin type syringe to accurately measure dosages. The rubber stopper can be punctured safely a maximum of 25 times.
Advise on correct administration
When using the product in combination with other products, the SPCs should be read carefully and all warnings and contraindications observed.
Do not reverse ketamine-medetomidine combinations in dogs and cats with atipamezole until 45 minutes after ketamine administration, when ketamine action has ceased.
Pre-surgical preparation: As for all anaesthetics animals should be fasted for at least 12 hours before ketamine anaesthesia.
Anaesthetic period: Under ketamine anaesthesia the eyes of treated animals remain open, therefore to prevent desiccation in case of longer lasting procedures they should be protected accordingly (by use of appropriate ointments).
Recovery period: It is important that both premedication and recovery should occur in quiet and calm surroundings. Recovery usually is complete after 2 hours, but may occasionally take longer. In dogs, states of psychomotoric excitation with howling can rarely be observed.