Anesketin

For administration by intramuscular, subcutaneous or intravenous injection. For combination use: before ketamine is administered, please ensure that the animals are adequately sedated.It should be noted that dosages and routes of administration vary widely between species. Furthermore, the effect of ketamine may show large inter-individual differences and therefore, individual dosage accommodation is recommended.

To ensure a correct dosage, body weight should be determined as accurately as possible.

DOG:

Ketamine cannot be used as a mono-anaesthetic in dogs, as it causes an increased muscle tone and uncoordinated muscle contractions.

Xylazine/ketamine:

Administer xylazine at a dose rate of 1 mg/kg by intramuscular injection

(corresponding to 0.5 ml/10 kg body weight of xylazine 2% solution). Immediately administer ketamine at a dose rate of 15 mg/kg by intramuscular injection (corresponding to 1.5 ml/10 kg body weight).

Dogs become recumbent in approximately 3 minutes and lose their pedal reflex in approximately 7 minutes. Duration of anaesthesia is approximately 24 minutes, the pedal reflex returning about 30 minutes following administration of the ketamine injection.

Table 1: Xylazine and ketamine 100 mg/ml canine anaesthesia (IM)

* based on a dose rate of 1 mg xylazine/kg body weight ** based on a dose rate of 15 mg ketamine/kg body weight

Medetomidine/ketamine:

Administer medetomidine at a dose rate of 40 µg/kg (corresponding to 0.40 ml/10 kg body weight of medetomidine 1 mg/ml solution) and ketamine at 5.0-7.5 mg/kg (corresponding to 0.5-0.75 ml/10 kg body weight), depending on duration of anaesthesia required, by intramuscular injection.

Loss of pedal reflex occurs approximately 11 minutes following injection at 5 mg ketamine/kg and 7 minutes following injection at 7.5 mg ketamine/kg. Duration of anaesthesia is approximately 30 and 50 minutes respectively.

It is NOT advisable to reverse this combination in the dog with atipamezole.

Table 2: Medetomidine and ketamine canine anaesthesia (IM): Dosage chart for

5 mg ketamine/kg (duration of anaesthesia approximately 30 minutes)

* based on a dose rate of 40 µg medetomidine/kg body weight

** based on a dose rate of 5 mg ketamine/kg body weight

Table 3: Medetomidine and ketamine canine anaesthesia (IM): Dosage chart for

7.5 mg ketamine/kg (duration of anaesthesia approximately 50 minutes)

* based on a dose rate of 40 µg medetomidine/kg body weight ** based on a dose rate of 7.5 mg ketamine/kg body weight

Butorphanol/medetomidine/ketamine:

Administer butorphanol at 0.1 mg/kg and medetomidine at 25 µg/kg by intramuscular injection.

Dogs become recumbent in approximately 6 minutes and lose their pedal reflex in approximately 14 minutes.

Ketamine injection should be administered 15 minutes following the first injection at a dose rate of 5 mg/kg by intramuscular injection (corresponding to 0.5 ml/10 kg body weight).

The pedal reflex returns approximately 53 minutes following administration of the ketamine 100 mg/ml injection. Sternal recumbency is attained approximately 35 minutes later followed by standing a further 36 minutes later.

It is NOT advisable to reverse this combination in the dog with atipamezole.

Table 4: Butorphanol, medetomidine and ketamine canine anaesthesia (IM)

* based on a dose rate of 0.1 mg butorphanol/kg body weight

** based on a dose rate of 25 µg medetomidine/kg body weight *** based on a dose rate of 5 mg ketamine/kg body weight

CAT:

Ketamine as a sole agent:

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 or subcutaneous injection, but intramuscular injection is the recommended route. The dose is 11-33 mg ketamine/kg depending on the degree of restraint or surgical interference that is intended. The following dosages are indicated as a guide but may need to be adjusted depending on the physical condition of the patient and the usage of sedatives and premedicants.

Duration of ketamine anaesthesia is 20-40 minutes and recovery takes place over a 1-4 hour period.

For major surgery, ketamine should be used in conjunction with supplemental sedatives or anaesthetics. Dosage varies from 1.25-22 mg/kg (0.06-1.1 ml/5 kg) depending on the combination and route of administration used.

Vomiting is unlikely to occur when ketamine is used alone, however, cats should be starved for several hours prior to anaesthesia where possible.

Ketamine supplementary combinations in the cat:

Atropine premedication is generally recommended at 0.05 mg/kg to reduce salivation.

In addition, acepromazine (0.2% solution) at a dose rate of 0.11 mg/kg

(corresponding to 0.28 ml/5 kg body weight) can be administered by intramuscular injection, as premedicant. Endotracheal intubation can be achieved during ketamine anaesthesia. Inhalation anaesthesia may be maintained by suitable combinations of methoxyflurane, halothane, nitrous oxide and oxygen.

Xylazine/ketamine:

Administer xylazine at a dose rate of 1.1 mg/kg (corresponding to 0.28 ml/5 kg body weight of xylazine 2% solution) and atropine at a dose rate of 0.03 mg/kg (corresponding to 0.25 ml/5 kg body weight of atropine 0.06% solution) by intramuscular injection. Wait 20 minutes and then administer ketamine at a dose rate of 22 mg/kg (corresponding to 1.1 ml/5 kg body weight) by intramuscular injection. Xylazine may induce vomiting up to 20 minutes after administration. Onset of anaesthesia after intramuscular injection of ketamine takes some 3-6 minutes.

A xylazine/ketamine combination produces a deeper anaesthesia with more pronounced respiratory and cardiac effects and a longer recovery period than acepromazine/ketamine combinations.

Table 5: Xylazine and ketamine feline anaesthesia (IM)

* based on a dose rate of 1.1 mg xylazine/kg body weight

** based on a dose rate of 0.03 mg atropine/kg body weight *** based on a dose rate of 22 mg ketamine/kg body weight

Medetomidine/ketamine:

Intramuscular:

Administer medetomidine at a dose rate of 80 µg/kg by intramuscular injection. This should be followed immediately by the intramuscular injection of ketamine at a dose rate of 2.5-7.5 mg/kg (corresponding to 0.12-0.38 ml/5 kg body weight). Onset of anaesthesia is 3-4 minutes. The duration of surgical anaesthesia varies between 30-60 minutes and is related to the dose of ketamine used. If required, anaesthesia may be prolonged with halothane and oxygen with or without nitrous oxide.

Table 6: Medetomidine and ketamine feline anaesthesia (IM)

* based on a dose rate of 80 µg medetomidine/kg body weight** based on a dose rate of 5 mg ketamine/kg body weight

Intravenous:

Medetomidine and ketamine may be administered by intravenous injection at the following dose rates: 40 µg medetomidine/kg and 1.25 mg ketamine/kg. Clinical experience has shown that when ketamine and medetomidine have been used intravenously in cats and the need for anaesthesia has passed, administration of 100 µg atipamezole/kg by intramuscular injection results in recovery to sternal recumbency in approximately 10 minutes and to standing in approximately 14 minutes.

Table 7: Medetomidine and ketamine feline anaesthesia (IV)

* based on a dose rate of 40 µg medetomidine/kg body weight

** based on a dose rate of 1.25 mg ketamine/kg body weight

Atropine is not normally necessary when using a medetomidine/ketamine combination.

Use of either insulin syringes or 1 ml graduated syringes is recommended to ensure accurate dosing.

Butorphanol/medetomidine/ketamine:

Intramuscular:

Administer butorphanol at a dose rate of 0.4 mg/kg, medetomidine at a dose rate of 80 µg/kg and ketamine at a dose rate of 5 mg/kg (corresponding to 0.25 ml/5 kg body weight) by intramuscular injection.

Cats become recumbent in 2-3 minutes following injection. Loss of pedal reflex occurs 3 minutes post injection. At 45 minutes post induction, reversal with 200 µg atipamezole/kg results in return of pedal reflex 2 minutes later, sternal recumbency 6 minutes later and standing 31 minutes later.

Table 8: Butorphanol, medetomidine and ketamine feline anaesthesia (IM)

* based on a dose rate of 0.4 mg butorphanol/kg body weight

** based on a dose rate of 80 µg medetomidine/kg body weight

*** based on a dose rate of 5 mg ketamine/kg body weight

Intravenous:

Administer butorphanol at a dose rate of 0.1 mg/kg, medetomidine at a dose rate of 40 µg/kg and ketamine, depending on depth of anaesthesia required, at a dose rate of 1.25-2.5 mg/kg (corresponding to 0.06-0.13 ml/5 kg body weight) by intravenous injection.

Approximate time scales when using the triple combination intravenously:

* in conjunction with butorphanol at 0.1 mg/kg and medetomidine at 40 µg/kg

Clinical experience has shown that reversal, at any stage, with 100 µg atipamezole/kg results in return of the pedal reflex 4 minutes later, sternal recumbency 7 minutes later and standing 18 minutes later.

Table 9: Butorphanol, medetomidine and ketamine feline anaesthesia (IV): Dosage chart for 2.5 mg/kg ketamine (duration of anaesthesia approximately 28 minutes)

* based on a dose rate of 0.1 mg butorphanol/kg body weight

** based on a dose rate of 40 µg medetomidine/kg body weight *** based on a dose rate of 2.5 mg ketamine/kg body weight

HORSE:

For the production of short term anaesthesia suitable for minor surgical interferences or for induction prior to inhalation anaesthesia. When romifidine or detomidine are used as the premedicant, anaesthesia may also be maintained with a ‘top-up’ combination of either romifidine and ketamine 100 mg/ml or detomidine and ketamine at regular 8-10 minute intervals. Ketamine should never be used as a sole anaesthetic agent.

It is generally accepted as good anaesthetic practice to starve animals for a period prior to anaesthesia where possible.

To achieve the best results, it is important that horses are not stressed before the anaesthetic. It is equally important that the whole procedure, from induction to recovery, should take place in quiet and calm surroundings.

For horses that are stressed before the procedure, the use of 0.03 mg/kg acepromazine 45 minutes prior to administration of either detomidine or romifidine facilitates handling and placement of an intravenous catheter.

If the horse fails to become sedated following the injection of either xylazine, detomidine or romifidine, then ketamine should not be injected and the anaesthetic procedure should be abandoned. The situation should be assessed to establish why the horse failed to respond, and then the environment and/or the drugs should be adjusted as necessary, before trying again the following day.

When using a total intravenous technique and for safe and effective use of a top-up regime, the use of an intravenous catheter is strongly advised.

During castration it has been noted that the use of 10 ml lidocaine divided between the testicles eliminates the possible response to ligation of the testicular cord and minimises the number of top-ups required.

Xylazine/ketamine:

Xylazine should be administered by slow intravenous injection at a dose rate of 1.1 mg/kg (corresponding to 1.1 ml/100 kg body weight of xylazine 10% solution). The horse should appear sedated within 2 minutes post injection. Injection of ketamine should be administered at this stage. It is recommended not to delay the ketamine injection longer than 5 minutes after xylazine administration. Ketamine should be administered as an intravenous bolus at a dose rate of 2.2 mg/kg (corresponding to 2.2 ml/100 kg body weight).

Induction and recumbency take some 1-2 minutes. Muscle jerking may occur in the first minutes, but this usually subsides.

Anaesthesia is variable in duration, lasting between 10 and30 minutes, but usually less than 20 minutes. Horses invariably stand 25-45 minutes after induction. Recovery is generally quiet, but may occur suddenly. It is important therefore that short duration interferences only are attempted, or arrangements to prolong anaesthesia are made. For longer periods of anaesthesia, intubation and maintenance by inhalation anaesthesia can be used.

Table 10: Xylazine and ketamine equine anaesthesia (IV)

* based on a dose rate of 1.1 mg xylazine/kg body weight ** based on a dose rate of 2.2 mg ketamine/kg body weight

Detomidine/ketamine:

Detomidine should be administered by intravenous injection at a dose rate of 20 µg/kg. The horse should appear sedated within five minutes post injection. At this stage ketamine should be administered at a dose rate of 2.2 mg/kg (corresponding to 2.2 ml/100 kg body weight) as an intravenous bolus.

Onset of anaesthesia is gradual; most horses take approximately 1 minute to become recumbent. Large, fit horses may take up to 3 minutes for recumbency. Anaesthesia continues to deepen for a further 1-2 minutes and during this time the horse should be left quietly. Horses regain sternal recumbency approximately 20 minutes post ketamine injection giving a surgical anaesthesia duration of 10-15 minutes.

Maintenance of surgical anaesthesia:

Should it become necessary to prolong anaesthesia, either of the following regimes may be used:

a) Thiopental sodium

Thiopental sodium may be administered intravenously in boluses of 1 mg/kg as required. Total doses of 5 mg/kg (five 1 mg/kg increments) have been given. Total doses greater than this may reduce the quality of recovery. Thiopental sodium can also be administered in increments if sufficient depth of anaesthesia is not achieved. The horse may be ataxic if encouraged to stand prematurely and so should be left to stand in its own time.

b) Detomidine/ketamine

Administer 10 µg detomidine/kg, i.e. ½ the initial premedication dose by intravenous injection, followed immediately by 1.1 mg ketamine/kg, i.e. ½ the initial induction dose by intravenous injection. This will provide approximately 10 minutes additional surgical anaesthesia, which can be repeated at regular 10 minute intervals (up to 5 times) without compromising recovery.

Table 11: Detomidine and ketamine equine anaesthesia (IV): Premedication and induction of anaesthesia

* based on a dose rate of 20 µg detomidine/kg body weight

** based on a dose rate of 2.2 mg ketamine/kg body weight

Table 12: Detomidine and ketamine equine anaesthesia (IV): Maintenance (topup) dose at 10 minute intervals

* based on a dose rate of 10 µg detomidine/kg body weight ** based on a dose rate of 1.1 mg ketamine/kg body weight

Romifidine/ketamine:

Romifidine should be administered by intravenous injection at a dose rate of 100 µg/kg. The horse should appear sedated by five to ten minutes post injection. At this stage ketamine should be administered at a dose rate of 2.2 mg/kg (corresponding to 2.2 ml/100 kg) as an intravenous bolus. Sedation should be apparent before the induction of anaesthesia.

Maintenance of surgical anaesthesia:

Should it become necessary to prolong anaesthesia, either of the following regimes may be used:

a) Thiopental sodium

Thiopental sodium may be administered intravenously in boluses of 2.5 mg/kg when signs of returning consciousness appear. This can be repeated up to 3 times after induction. Total doses greater than this may reduce the quality of recovery. The horse may be ataxic if encouraged to stand prematurely and so should be left to stand in its own time.

b) Romifidine/ketamine

Depending on depth and duration of anaesthesia required, administer romifidine intravenously within the dose range of 25-50 µg/kg body weight, i.e. ¼-½ the initial premedication dose followed immediately by ketamine intravenously at a dose rate of

1.1 mg/kg body weight, i.e. ½ the initial induction dose). Each top-up lasts approximately 8-10 minutes and can be repeated at regular 8-10 minute intervals (up to 5 times) without compromising recovery.

Table 13: Romifidine and ketamine equine anaesthesia (IV): Premedication and induction of anaesthesia

* based on a dose rate of 100 µg romifidine/kg body weight

** based on a dose rate of 2.2 mg ketamine/kg body weight

Table 14: Romifidine and ketamine equine anaesthesia (IV): Maintenance (topup) dose at 8-10 minute intervals

* based on a dose rate of 50 µg romifidine/kg body weight

** based on a dose rate of 1.1 mg ketamine/kg body weight