Target species
Horses
Indications for use
Anaesthetic Premedication: Following acepromazine administration, the amount of anaesthetic necessary to induce anaesthesia is considerably reduced.
Tranquilisation: Acepromazine tranquilisation (ataraxy) involves a modification of temperament which is not associated with hypnosis, narcosis or marked sedation. This is achieved with low doses of acepromazine. At low doses, acepromazine reduces anxiety which is beneficial for use in horses prior to shoeing or transportation.
Sedation: At higher dose rates acepromazine is an effective sedative, as an adjunct to, or replacement for, physical restraint e.g. dentistry, handling and shoeing. The relaxant effects aid examination of the penis in horses and the treatment of tetanus and choke.
Contraindications
Do not use in cases of hypersensitivity to the active substance or to any of the excipients.
Do not administer to breeding stallions. See Adverse reactions.
Do not use in pregnant mares.
Do not use in animals in existing severe emotional excitation.
Special warnings for each target species
Acepromazine has little, if any, analgesic effect so that painful procedures must be avoided, particularly where animals are known to have unpredictable temperaments. Therefore, the usual precautions should be maintained when handling sedated horses.
During sedation, horses will normally retain visual and auditory acuity, so that loud sounds and rapid movements may cause arousal from the sedated state. It is therefore important to keep treated horses in a quiet environment and avoid sensory stimulation as far as possible.
Special precautions for use in animals
Situations may arise where general anaesthesia is required in the 4−6 hours following use of the product. In such cases care should be taken to reduce the dose of other premedicants and anaesthetic agents, particularly parenteral barbiturates, so as to avoid potentiation and additive depressant effects.
When administered to male horses (geldings or non-breeding stallions), use the lowest dose recommended to produce the required effect.
Acepromazine may cause hypothermia due to depression of the thermoregulatory centre and peripheral vasodilation.
Acepromazine is an adrenoceptor blocking drug and this causes hypotension and lowered haematocrit. The product should therefore be administered with great caution, and at low dose rates only to debilitated horses and animals in states of hypovolaemia, anaemia and shock, or with cardiovascular disease. Rehydration should precede acepromazine administration.
Duration of action may be prolonged and this should be remembered when riding, as acepromazine may affect performance and appear in drug tests for some time.
Special precautions to be taken by the person administering the veterinary medicinal product to animals
This product contains a potent sedative; care should be taken, when handling and administering the product, to avoid accidental self-exposure.
In case of accidental self-injection, seek medical advice immediately and show the package insert or the label to the physician but DO NOT DRIVE as sedation and changes in blood pressure may occur. Symptomatic treatment may be required.
If accidental eye contamination occurs, flush gently with fresh running water for 15 minutes. Medical advice should be sought if irritation persists.
In the event of accidental skin contamination, contaminated clothing should be removed and the area washed with large amounts of soap and water. Medical advice should be sought if irritation persists.
Wash hands and exposed skin thoroughly after use.
Adverse reactions
Acepromazine may cause hypotension (common) and lowered haematocrit (very common). Reversible paralysis of the retractor penis muscle has been associated with the use of parenterally administered acepromazine in horses (very common). Acepromazine has caused paraphimosis (uncommon), sometimes as a sequel to priapism, however this only very rarely results in permanent penile dysfunction. When extrusion of the penis occurs, the owner should be advised to inform his veterinary surgeon if retraction of the penis does not take place within 2−3 hours. Suitable treatments have been described in the veterinary literature e.g. manual compression during the period of general anaesthesia, penile support and manual compression, use of an Esmarch bandage, or drug reversal (e.g. slow intravenous administration of benztropine mesylate).
Accidental intracarotid injection in horses can produce clinical signs ranging from disorientation to convulsive seizures and death.
The frequency of adverse reactions is defined using the following convention:
- very common (more than 1 in 10 animals treated displaying adverse reactions(s))
- common (more than 1 but less than 10 animals in 100 animals treated)
- uncommon (more than 1 but less than 10 animals in 1,000 animals treated)
- rare (more than 1 but less than 10 animals is 10,000 animals treated)
- very rare (less than 1 animal in 10,000 animals treated, including isolated reports).
Use during pregnancy and lactation
Do not administer to pregnant mares. The safety of the veterinary medicinal product has not been established during pregnancy or lactation.
Interactions
Phenothiazines are additive to the actions of other CNS depressants and will potentiate general anaesthesia (see Indications for use).
Do not use this product in conjunction with organophosphates and/or procaine hydrochloride, as it may enhance activity and potential toxicity.
Amounts to be administered and administration route
For intramuscular or intravenous injection. In case of intravenous injection, it is recommended the injection is made slowly.
0.03−0.10 mg acepromazine per kg body weight, equivalent to 0.15−0.5 ml product per 50 kg body weight.
Normally, single doses of acepromazine are administered. Long term use is not recommended. On the rare occasions that repeat dosing is required, the dosing interval should be 36−48 hours.
Take adequate precautions to maintain sterility. Avoid the introduction of contamination during use. Should any apparent growth or discolouration occur, discard the product.
The maximum number of vial punctures when using needle sizes of 21G and 23G should not exceed 100 and when using a 18G needle, the maximum should not exceed 40.
Overdose
Transient dose-dependent hypotension may occur in cases of accidental overdose. Therapy should consist of discontinuing any other hypotensive treatment, supportive care such as intravenous infusion of warm isotonic saline to correct hypotension and close monitoring. In severe cases treatment with norepinephrine may be indicated but its use must be based on a careful evaluation of the benefit risk balance by the responsible veterinary surgeon.
Epinephrine (adrenaline) is contra-indicated in the treatment of acute hypotension produced by overdosage of acepromazine maleate, since further depression of systemic blood pressure can result.
Withdrawal periods
The product is not authorised for use in horses intended for human consumption.