Nerfasin 20 mg/ml, Solution for Injection for Cattle, Horses, Dogs and Cats

Horses:
• Xylazine inhibits the normal intestinal motility. Therefore, it should only be
used in horses with colic, that are not responsive to analgesics. The use of
xylazine should be avoided in horses with caecal malfunction.
• After treatment of horses with xylazine, the animals are reluctant to walk, so
whenever possible the drug should be administered in the place where the
treatment/investigation is going to take place.
• Caution should be taken in the administration of the product to horses
susceptible to laminitis.
• Horses with airway disease or malfunction may develop life-threatening
dyspnoea.
• The dose should be kept as low as possible.
• The association with other pre-anaesthetic agents or anaesthetic agents
should be the subject of a benefit/risk assessment. This assessment should
consider the composition of the products, their dose and the nature of the
surgery. Recommended dosages are likely to vary according to the choice of
the anaesthetic association.
Cats and dogs:
• Xylazine inhibits the normal intestinal motility. This may make xylazine
sedation undesirable for upper gastro-intestinal radiographs, because it
promotes filling of the stomach with gas and makes interpretation less
certain.
• Brachycephalic dogs with air way disease or malfunction may develop life-
threatening dyspnoea.
• The association with other pre-anaesthetic agents or anaesthetic agents
should be the subject of a benefit/risk assessment. This assessment should
consider the composition of the products, their dose and the nature of the
surgery. Recommended dosages are likely to vary according to the choice of
the anaesthetic association.
Cattle:
• Ruminants are highly susceptible to the effects of xylazine. Normally cattle
remain standing at the lower doses, but some animals may lie down. At the
highest recommended doses most animals will lie down and some animals
may lapse in lateral recumbency.
• Reticulo-ruminal motor functions are depressed after injection of xylazine.
This may results in bloat. It is advisable to withhold feed and water for
several hours before administration of xylazine.
• In cattle the ability to eructate, cough and swallow is retained but reduced
during the period of sedation, therefore cattle must be closely watched
during the recovery period: the animals should be maintained in sternal
recumbency.
• In cattle life threatening effects may occur after intramuscular doses above
0.5 mg/kg body weight (respiratory and circulatory failure). Therefore very
precise dosing is required.

Revised: August 2017
AN: 01201/2016
• The association with other pre-anaesthetic agents or anaesthetic agents
should be the subject of a benefit/risk assessment. This assessment should
consider the composition of the products, their dose and the nature of the
surgery. Recommended dosages are likely to vary according to the choice of
the anaesthetic association.

Special precautions for use in animals
Keep the animals calm, because they may respond to external stimuli.
Avoid intra-arterial administration.
Tympany may occasionally occur in recumbent cattle and can be avoided by
maintaining the animal in sternal recumbency.
To avoid aspiration of saliva or food, lower the animal’s head and neck. Fast
the animals before use of the product.
• Older and exhausted animals are more sensitive to xylazine, whilst nervous
or highly excitable animals may require a relatively high dose.
• In case of dehydration, xylazine should be used cautiously.
• Emesis is generally seen within 3-5 minutes after xylazine administration in
cats and dogs. It is advisable to fast dogs and cats for 12 hours prior to
surgery; they may have free access to drinking water.
• Pre-medication with atropine in cats and dogs may reduce salivation and
bradycardia effects
• Do not exceed the recommended dosage.
• Following administration animals should be allowed to rest quietly until the
full effect has been reached.
• It is advised to cool animals when the ambient temperature is above 25°C
and to keep animals warm at low temperatures.
• For painful procedures, xylazine should always be used in combination with
local or general anaesthesia.
• Xylazine produces a certain degree of ataxia; therefore, xylazine must be
used cautiously in procedures involving the distal extremities and in standing
castrations in the horse.
• Treated animals should be monitored until the effect has faded totally (e.g.
cardiac and respiratory function, also in the post-operative phase) and
should be segregated to avoid bullying.
• For use in young animals, see the age restriction mentioned in section 4.3. If
the product is intended to be used in young animals below these age-limits,
a benefit/risk assessment should be made by the veterinarian.
Special precautions to be taken by the person administering the veterinary
medicinal product to animals
• Care should be taken to avoid accidental self-injection. In case of accidental
oral intake or self-injection, seek medical advice immediately and show the
package leaflet to the physician but DO NOT DRIVE as sedation and
changes in blood pressure may occur.
• Avoid skin, eye or mucosal contact.
• Wash the exposed skin immediately after exposure with large amounts of

Revised: August 2017
AN: 01201/2016
water.
• Remove contaminated clothes that are in direct contact with skin.
• In the case of accidental contact of the product with eyes, rinse abundantly
with fresh water. If symptoms occur, seek the advice of a physician.
• If pregnant women handle the product, special caution should be observed
not to self-inject as uterine contractions and decreased foetal blood pressure
may occur after accidental systemic exposure.
Advice to doctors:
Xylazine is an agonist, symptoms after absorption may
involve clinical effects including dose-dependent sedation, respiratory
depression, bradycardia, hypotension, a dry mouth and hyperglycaemia.
Ventricular arrhythmias have also been reported. Respiratory and
haemodynamic symptoms should be treated symptomatically.