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Contra-indications, warnings, etc
Do not use in case of hypersensitivity to the active substance or to any of the excipients.
Do not use for treatment of animals with severe dysfunction of the liver and kidneys, in case of cerebral injury or organic brain lesions and in animals with obstructive respiratory diseases, heart dysfunctions or spastic conditions.
For combination use with α2-agonists in horses:
Do not use in horses with a pre-existing cardiac dysrhythmia. The combination will cause a reduction in gastrointestinal motility and consequently should not be used in cases of colic associated with impaction. Do not use combination during pregnancy.
Adverse reaction
Undesirable effects are generally related to the known activity of opioids. In published trials with butorphanol, transient ataxia, lasting about 3 to 15 minutes, occurred in about 20 % of horses. Mild sedation occurred in about 10 % of horses. Increased motor activity (running movements) is possible.
Gastrointestinal motility may be reduced.This effect is mild and transient.
For combination use:
Any reduction of gastrointestinal motility caused by butorphanol may be enhanced by the concomitant use of α2-agonists. The respiratory depressive effects of α2-agonists may be enhanced by concomitant butorphanol, particularly if respiratory function is already impaired. Other undesirable effects (e.g. cardiovascular) are likely to be related to the α 2-agonist.
Depression of the respiratory and cardiovascular system. Local pain associated with intramuscular administration. Decreased gastrointestinal motility. In rare cases, ataxia, anorexia and diarrhoea. In cats excitation or sedation, anxiety, disorientation, dysphoria and mydriasis are possible.
If you notice any serious effects or other effects not mentioned in this leaflet, please inform your veterinary surgeon.
Special warnings
The precautionary measures required for contact with animals should be followed and stress factors for the animals should be avoided.
In cats, individual response to butorphanol may be variable. In the absence of an adequate analgesic response, an alternative analgesic agent should be used.
Increasing of the dose may not increase the intensity or duration of analgesia.
Special precautions for use in animals
The safety of the product in puppies, kitten and foals has not been established. Use of the product in these groups should be on the basis of a risk-benefit analysis by the responsible veterinarian.
Due to its antitussive properties, butorphanol may lead to an accumulation of mucous in the respiratory tract. Therefore, in animals with respiratory diseases associated with increased mucous production, butorphaol should only be used after a risk-benefit evaluation by the responsible veterinarian. If respiratory depression occurs, naloxone may be used as an antidote.
Sedation may be noted in treated animals. The combination of butorphanol and α2-adrenoceptor agonists should be used with caution in animals with cardiovascular disease. The concurrent use of anticholinergic drugs e.g atropine should be considered.
Administration of butorphanol and romifidine in one syringe should be avoided due to increased bradycardia, heart block and ataxia.
The use of the product at the recommended dose may lead to transient ataxia and/or excitement. Therefore, to prevent injuries in patient and people when treating horses, the location for the treatment should be chosen carefully.
Cats should be weighed to ensure that the correct dose is calculated. An appropriate graduated syringe must be used to allow accurate administration of the required dose volume (e.g. insulin syringe or 1 ml graduated syringe). If repeated administrations are required, use different injection sites.
Interaction with other medicinal products
The concomitant administration of other drugs which are metabolised in the liver may enhance the effect of butorphanol.
Butorphanol used with concurrently administered anaesthetics, centrally sedative or respiratory depressive drugs produces additive effects. Any use of butorphanol in this context requires acute control and a careful adaptation of the dose.
Administration of butorphanol may remove the analgesic effect in animals, which have already received pure μ-opioid analgesics.
Increased dosages could result in respiratory depression as a general opioid effect. Intravenous doses of 1.0 mg/kg (10 x the recommended dose), repeated at 4-hourly intervals for 2 days, led to transient adverse effects, including pyrexia, tachypnoea, CNS signs (hyperexcitability, restlessness, mild ataxia leading to somnolence) and gastrointestinal hypomotility, sometimes with abdominal discomfort. An opioid antagonist (e.g. Naloxone) may be used as an antidote.
Miosis (dog)/Mydriasis (cat), respiratory depression, hypotension, disorders of the cardiovascular system and in severe cases respiratory inhibition, shock and coma. Depending on the clinical situation counter-measures should be taken under intense medical monitoring. Monitoring is required for a minimum of 24 hours.
Use during pregnancy and lactation
Butorphanol crosses the placental barrier and penetrates into milk. Studies in laboratory species have not produced any evidence of teratogenic effects.
The safety of this veterinary medicinal product has not been established in the target species during pregnancy and lactation. The use of butorphanol during pregnancy and lactation is not recommended.
User warnings
Butorphanol has opioid-like activity. Precautions should be taken to avoid accidental injection/self-injection with this potent drug. The most frequent adverse effects of butorphanol in humans are drowsiness, sweating, nausea, dizziness and vertigo and may occur following unintended self-injection. If accidental self-injection occurs, seek medical advice immediately and show the package leaflet or the label to the physician. Do not drive. An opioid antagonist (e.g. naloxone) may be used as an antidote. Wash splashes from skin and eyes immediately
Withdrawal period
Horse (meat & offal): Zero days
Horse (milk): zero hours