Xylazine as hydrochloride 100 mg/mL
Randlab Xylazine 100 is an injection containing 100 mg/mL (10% w/v) of Xylazine for use as sedative, analgesic and skeletal muscle relaxant in horses. Randlab Xylazine 100 produces dose dependent sedation and analgesia through an alphamimetic and direct opioid effect. It also produces muscle relaxation by inhibition of the intraneuronal transmission of impulses centrally in the CNS. Onset of action is rapid with effective sedation present within 3-5 minutes after intravenous injection and within 10-15 minutes following intramuscular or subcutaneous administration.
The sedative effect usually lasts 1-2 hours, while the analgesic effect lasts only 30-40 minutes. The usual response to Xylazine 100 administration in the horse is drooping of the head, ataxia without recumbency, penile prolapse which does not progress to paraphimosis, and pendulous lower lip. Complete recovery varies with the dose administered, however, it is usually uneventful and requires minimal supervision.
DIRECTIONS FOR USE
Horse Hack: Horses should not be fed until they have fully recovered from sedation due to the risk of oesophageal choke.
Randlab Xylazine 100 is an extremely useful sedative in the horse, allowing a number of procedures to be more easily conducted eg ophthalmic, dental or endoscopic examinations, wound suturing, rectal examination, stomach tubing, examination of fractious patients, diagnostic imaging, bandage application and removal etc. Xylazine in combination with appropriate local anaesthesia may be suitable for minor standing surgeries such as castration, dental procedures, draining abscesses, etc. Xylazine may provide short acting analgesia in cases of colic facilitating examination and transport. The visceral analgesia effect of xylazine has been demonstrated to be superior to that produced by butorphanol. Xylazine decreases digital blood flow for up to 8 hours after administration.
Randlab Xylazine 100 is also a very effective premedicant for both ketamine and barbiturate anaesthesia.
DOSAGE AND ADMINISTRATION
Horses: Dose dependent effect: 2.0-5.0mL per 450kg BW by slow IV injection. Draft horses are more sensitive to the effects of xylazine and the dose should be lowered accordingly.
Sedation: 1.1 mg/kg IV or 2.2 mg/kg IM. Allow animal to rest quietly until full effect is reached.
Colic: 0.2-0.5mg/kg IV will provide analgesia for 20-30 minutes. For longer duration, 0.6-1mg/kg IM will provide analgesia for 1-2 hours.
CRI for analgesia: 0.5-1.1 mg/kg IV followed by 0.72 mg/kg/ hour.
Caudal epidural: 0.03-0.35 mg/kg in first coccygeal space. 3-5 hour duration of effect.
Field induction: 1.1mg/kg IV. Wait until full sedation is achieved (5-10 min). If adequate sedation does not occur, re-dose with half the original dose of xylazine. Then follow with 2.2mg/kg IV of ketamine. Butorphanol (0.02-0.04mg/kg IV) or diazepam (0.03mg/kg IV) may be added before the ketamine for additional sedation, analgesia or muscle relaxation respectively.
“Triple drip” anaesthesia: Add 500mg xylazine and 2000mg ketamine to 1L of 5% guaifenesin in dextrose or 0.9% saline.
Induction: 1.1 mL/kg IV rapidly.
Maintenance: 2.0 -4.5 mL/kg/hr to effect. “Triple drip” should not be used for anaesthetics greater than 1 hour in duration unless oxygen supplementation and respiratory support is provided.
Foals & Ponies: Add 250mg xylazine and 500mg ketamine to 500mL 5% guaifenesin solution. For induction give 1.1 mL/ kg IV rapidly. For maintenance 2-3mL/kg/hr to effect.
Reversal: Tolazoline, atipamezole or yohimbine may be used alone or in combination to reverse the effects of xylazine or speed recovery..
Horse Hack: Inadvertent intra-arterial (eg carotid artery) administration of xylazine will result in extreme excitement and convulsions. The horse will normally recover within 10 minutes but is at high risk of sustaining an injury whilst convulsing.
It is normal for Randlab Xylazine 100 to cause cardiopulmonary depression manifested by a decrease in heart rate, stroke volume, cardiac output and respiratory rate together with an increase in total peripheral resistance. These effects are transitory and of no clinical significance in healthy horses. However, it is not recommended to use Randlab Xylazine 100 where there is cardiovascular disease including conditions of shock, or respiratory depression.
A number of cardiac dysrhythmias such as second degree AV block have been encountered with xylazine administration due to increased vagal tone.
Painful stimuli may cause an apparently deeply sedated patient to react inappropriately (eg kicking or striking) and therefore adequate care should be taken..
APVMA Approval No. 87320/118091 (Australia)