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Dosage and administration
Target species: Horses
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 Once the required dose has been withdrawn from the vial, the syringe should be removed from the needle.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
To be administered intramuscularly or by slow intravenous injection. Onset of effect is more rapid following intravenous administration.
Dosage table
Anticipated level of sedation
Dosage (IM or IV) µ/kg
10 - 20
20 - 40
40 - 80
Dose (IM or IV) ml/100 kg
0.1 - 0.2
0.2 - 0.4
0.4 - 0.8
Domosedan with butorphanol for sedation
Dosage: 0.10 ml Domosedan/100 kg (10 µ/kg detomidine hydrochloride) intravenously, followed within 5 minutes by a dose rate in the region of 25 µ/kg butorphanol (e.g. 0.25ml/100kg of a 10mg/ml solution), intravenously.
Clinical experience has shown that 5 mg detomidine (0.5 ml Domosedan) and 10mg butorphanol (e.g. 1 ml 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. 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. It is important that, to obtain satisfactory surgical anaesthesia the following procedure is followed:
Administer the product at a dose rate of 20 µg/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 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 the product, then ketamine should not be injected and the anaesthesia procedure should be abandoned.