DOSAGE AND ADMINISTRATION:
The following procedure is recommended: Use two sterile needles, one to fill the syringe from the bottle and one to inject the patient. Once the required dose has been withdrawn from the vial, the syringe should be removed from the needle. A separate sterile needle should be inserted into the injection site and the syringe connected to it. The needles should be discarded.
Domosedan alone for sedation
For parenteral use by intramuscular or slow intravenous injection. Onset of effect is more rapid following intravenous administration.
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Dosage table
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Anticipated level of sedation
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Light
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Moderate
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Profound
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Dosage (IM or IV) mcg/kg
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10 - 20
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20 - 40
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40 - 80
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Dose (IM or IV) ml/100 kg
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0.1 - 0.2
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0.2-0.4
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0.4 - 0.8
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Domosedan with butorphanol for sedation
Dosage: 0.10 ml Domosedan/100 kg (10 mcg/kg detomidine hydrochloride) intravenously, followed within 5 minutes by a dose rate in the region of 25mcg/kg butorphanol (e.g. 0.25ml/100kg of a 10mg/ml solution), intravenously. Clinical experience has shown that 5mg detomidine (0.5ml Domosedan) and 10mg butorphanol (e.g. 1ml of a 10 mg/ml solution) affords effective, safe sedation in horses above 200 kg bodyweight.
Domosedan and ketamine (short duration anaesthesia)
Ketamine must not be used as the sole anaesthetic agent in horses. To obtain satisfactory surgical anaesthesia, it is important that the following procedure is used:
Administer Domosedan at a dose rate of 20 mcg/kg by slow intravenous injection.
Allow 5 minutes for the horse to become deeply sedated then administer ketamine at a dose rate of 2.2 mg/kg as an intravenous bolus.
Onset of anaesthesia is gradual, the horse taking approximately 1 minute to become recumbent. In large fit horses recumbency may take up to 3 minutes.
Anaesthesia will continue 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 administration.
The duration of surgical anaesthesia is approximately 10 - 15 minutes and if for any reason it is necessary to prolong anaesthesia, thiopentone sodium can 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.
Thiopentone can also be administered (as above regime) if sufficient depth of anaesthesia is not achieved.
The horse should be allowed to stand in its own time. The horse may be ataxic if it stands prematurely and therefore it should be encouraged to remain recumbent.
To facilitate handling and the administration of the induction agents, some horses have received acepromazine by intramuscular injection at a dose rate of 0.03 mg/kg at least 45 minutes before induction of anaesthesia.
Excitable horses are sometimes poor subjects for anaesthesia. It is a prime requisite that the horse should be quietly and carefully handled during the administration of the anaesthetic agents so as to ensure the minimum amount of upset during the induction period. If the horse fails to become sedated following the injection of Domosedan, then ketamine should not be injected and the anaesthetic procedure should be abandoned.
CONTRAINDICATIONS:
Before using any combinations consult the contraindications and warnings that appear on the other products' data sheets.
Do not administer to horses in the last month of pregnancy.
Do not use in conjunction with sympathomimetic amines or with intravenous potentiated sulphonamides.
It is always necessary to administer detomidine prior to ketamine and to allow sufficient time (5 minutes) for sedation to develop. The two agents must therefore never be administered simultaneously in the same syringe.
Do not use the butorphanol combination in horses suffering from colic.
Detomidine/butorphanol combination should not be used in horses with a history of liver disease or cardiac irregularities.
Precautions:
The product should not be used in horses with pre-existing AV blocks, with severe coronary insufficiency, respiratory disease or chronic renal failure.
Careful consideration should be given prior to administration to animals in shock and to animals with liver or kidney disease.
Intravenous administration should be slow.
It is recommended that feed should be withheld for at least 12 hours prior to anaesthesia.
The horse should not be given water or feed before the drug effect has passed.
Routine safety measures should be employed to protect practitioners and handlers.
ADVERSE REACTIONS:
Injection may cause benign reversible cardiac arrhythmia. Side effects such as sweating, incoordination of limbs and muscle tremor may occur after administration. A diuretic effect is usually observed within 45 to 60 minutes after treatment.
Use during pregnancy, lactation
Not to be used in mares in the last month of pregnancy.
Interactions:
Domosedan should not be mixed with other products.
Use with care with other sedatives and anaesthetics because of an additive/synergistic effect.
Where appropriate the product may be used in conjunction with local anaesthetic agents.
Induction of anaesthesia with detomidine and ketamine has been used prior to maintenance with halothane. Because of the nature of the induction agents, the effects of halothane may be delayed and special care must be taken to avoid over-dosage. When detomidine is used as a premedication prior to general anaesthesia, the product may delay onset of induction.
Use in conjunction with sympathomimetic amines and intravenous potentiated sulphonamides is contra-indicated.
Overdose:
In cases of overdose, or should the effects become life-threatening, an alpha-2 agonist (atipamezole) is recommended (5 - 10 times the dose of detomidine in mcg/kg)
