Xylamax (Canada)

Company: Bimeda-MTC

Xylazine Injection 100 mg/mL

Veterinary Use Only

Sedative and Analgesic for Horses

DIN 00805475

Sterile

Description

Xylamax (Xylazine HCl) Injection is a clear, colourless solution for intravenous or intramuscular administration supplied in 50 mL multiple-dose vials as a sterile solution.

Active Ingredient

Xylazine HCl equivalent to 100 mg/mL xylazine base.

Preservatives: 0.9 mg/mL methylparaben and 0.1 mg/mL propylparaben.

ACTIONS: Xylazine HCl is pharmacologically classified as a non-narcotic sedative with strong analgesic and hypnotic properties. ^1 2 3 4 Xylazine HCl produces muscle relaxation by inhibiting the intraneural transmission of impulse in the central nervous system. ^1 4 The drug produces sedation primarily through activation of alpha-adrenergic receptors in the locus coeruleus of the brain to prevent the release of norepinephrine and can be reversed with an alpha 2 adrenergic antagonist such as yohimbine. ⁵

Deep sedation develops in the animal within 10 to 15 minutes after intramuscular injection and within 3 to 5 minutes following intravenous administration. ^{1 2 4 6 7} Deep sedation lasts 15 to 20 minutes, while a sleep-like state, the depth of which is dose-dependent, is usually maintained for 1 to 2 hours following intramuscular administration of the drug at the recommended dosage. ^{1 2 4 6 7}

Recovery is complete within 30-40 minutes following intravenous injection. ^1 2 6 7 In either case, the analgesia lasts from 15-30 minutes. ^1 2 4

In animals under the influence of Xylazine HCl, the respiratory and pulse rates are reduced as in a natural sleep. ^1 3 4 5 The intramuscular injection of Xylamax (Xylamax HCl) produces only negligible effects on the cardiovascular and respiratory systems.

However, intravenous administration produces significant reductions in tidal volume and respiratory rate in the horse and pony although arterial oxygen and carbon dioxide levels are not appreciably altered. Xylamax (Xylamax HCl) may produce bradycardia which is severe enough to require treatment with an anticholinergic agent (atropine, glycopyrrolate) on rare occasions. Sinoatrial arrest, first, second and third degree A-V blocks and premature ventricular contractions have been observed. Arrhythmias may persist for up to three hours. ^{1 3 4 5 6 7} The cardiovascular system of the horse sedated with Xylazine HCl may not respond to stimulation (stress, hemorrhage) with an increased heart rate and cardiac output like a “normal horse”. ⁶ Xylazine HCl has no effect on blood clotting time or other hematologic parameters. ⁴

Indications: Horses- Xylamax (xylazine HCl) injection should be used when it is desirable to produce a state of sedation accompanied by a shorter period of analgesia. It has been successfully used when conducting various diagnostic, orthopedic and dental procedures and for minor surgical procedures of short duration. It may also be used as a preanesthetic to local or general anesthesia.

Dosage and Administration: Horses- For intravenous or intramuscular administration.

Sedation and analgesia- The recommended dosage for intravenous administration is 0.5 mL/45 kg body weight (equivalent to 1.1 mg/kg or 0.5 mg/lb). The recommended dosage for intramuscular administration is 1.0 mL/45 kg body weight (equivalent to 2.2 mg/kg or 1.0 mg/lb).

Following the administration of Xylamax (Xylamax HCl) Injection, the animal should be allowed to rest quietly until the full effect has been reached. These dosages produce a state of sedation which is usually maintained for 1 to 2 hours and analgesia which lasts for 15 to 30 minutes.

Preanesthetic to local anesthesia- At the recommended dosage rates, Xylamax (Xylamax HCl) Injection may be used in conjunction with local anesthetics, such as procaine and lidocaine.

Preanesthetic to general anesthesia- At the recommended dosage rates, Xylamax (Xylamax HCl) Injection produces an additive effect to central nervous system depressants, such as sodium pentobarbital, sodium thiopental and sodium thiamylal. Accordingly, the dosage of such compounds should be reduced and administered to the desired effect. Generally, 1/3 to 1/2 of the calculated dosage of barbiturates will be needed to produce a surgical plane of anesthesia. Postanesthetic or emergence excitement has not been observed in animals preanesthetized with Xylazine HCl Injection.

Xylamax (Xylamax HCl) Injection has been successfully used as a preanesthetic agent with a dose range of 0.3 to 0.6 mg/kg prior to sodium pentobarbital, sodium thiopental, sodium thiamylal, nitrous oxide, ether, halothane, glyceryl guaiacolate or methoxyflurane anesthesia. Xylamax can be used at full intravenous sedative dose (1.0 to 1.1 mg/kg) before ketamine HCl (Ketalean) induction.

Contraindications: Horses- Xylamax (Xylamax HCl) Injection should not be used in conjunction with neuroleptics or tranquilizers. ^1 4 5

WarningS: Horses- This drug is not to be administered to horses that are to be slaughtered for use in food. KEEP OUT OF REACH OF CHILDREN.

Cautions: Horses- Debilitated animals with depressed respiration, cardiac disease, renal and liver impairment, shock or any other stress conditions should be carefully monitored whenever Xylamax (Xylamax HCl) Injection is administered. ¹

Because Xylazine HCl produces an additive effect to central nervous system depressants, caution should be taken when administering barbiturate compounds in conjunction with Xylamax (Xylamax HCl) Injection. These drugs should be given at a reduced dosage to the desired effect and, when injected intravenously, should be given slowly.

Arrhythmias, resulting in partial A-V blocks, and bradycardia are transient changes which may occur, but these can be counteracted to a large degree by the administration of atropine prior to or following Xylamax (Xylamax HCl) Injection. ^1 3 4 5

Analgesic effect is variable, and depth should be carefully determined prior to surgical/clinical procedures. Variability of analgesia occurs most frequently at the distal extremities of the horse. In spite of sedation, the practitioner should proceed with caution, since defense reactions may not be diminished. Sedation for transport is most successful if the actual transportation is initiated after full effect of the drug has been obtained and the animal’s stability maintained in the standing position. It should be noted that animals under the influence of Xylazine HCl are particularly sensitive to noise and care should be taken accordingly to avoid risk of injury.

Intracarotid arterial injection should be avoided. As with many drugs, including tranquilizers, immediate and violent seizures, followed by collapse, may result from inadvertent administration into the carotid artery.

Although the reaction with Xylazine HCl is usually transient and the recovery rapid and complete, special care should be taken to ensure that the needle is in the jugular vein rather than the carotid artery. Xylazine HCl reduces gastrointestinal motility, decreases plasma insulin concentration and increases plasma glucose concentration and should be considered important in horses with gastrointestinal and hemodynamic disorders.

Side Effects: Horses- The deep sedation produced by Xylazine HCl is characterized by lowering of the head, drooping of the eyelids and lower lip and a marked reluctance to move. ^1 6 Most horses given Xylazine HCl sweat around the ears and poll region and may seem particularly sensitive to sharp auditory stimuli during the recovery period. ^1 4 6 7 The respiratory and pulse rate are reduced as in natural sleep. ^1 3 4 5 Transient changes in the conductivity of the cardiac muscle (resulting in partial A-V blocks), bradycardia, decreased cardiac output and a rise in arterial blood pressure may occur following intravenous administration. ^{1 3 4 5 6 7} Sudden death following Xylazine HCl administration has been reported in a stallion suffering from colic. ⁸

SAFETY: Horses- Xylazine HCl is tolerated in horses at 10 times the recommended dosage; however, doses of this magnitude produce muscle tremors and longer periods of sedation. At less than 10 times the recommended dosage, some horses may collapse and remain recumbent for a brief period of time.

Storage

Store at room temperature between 15°C - 30°C.

How Supplied

Xylamax (Xylazine HCl) Injection, 100 mg/mL, is available in 50 mL multiple-dose vials.

REFERENCES

1. Booth, N.H. and L.E. McDonald. 1982. Veterinary Pharmacology and Therapeutics, 5th ed. Iowa State University Press, Ames, IA. 311-316.

2. Rossoff, I.S. 1974. Handbook of Veterinary Drugs, Springer Publishing Co., New York, NY. 662.

3. Howard, J.L. 1981. Current Veterinary Therapy, Food Animal Practice. W.B. Saunders Co., Philadelphia, PA.

4. Grey, R.M. 1974. Veterinarians Product and Therapeutic Reference, 3rd ed. Edward Nottage, Publisher. 64-67.

5. Upson, D.W. 1985. Handbook on Clinical Veterinary Pharmacology, 2nd ed. Veterinary Medicine Publishing Co., Lenexa, KS. 216-218.

6. Hall, L.W. 1971. Wright’s Veterinary Anesthesia and Analgesia, 7th ed. Williams and Wilkins Co., Baltimore, MD. 161-163.

7. Soma, L.R. 1971. Textbook of Veterinary Anesthesia. Williams and Wilkins Co., Baltimore, MD. 324.

8. Fuentes, V.O. 1978. Veterinary Record. 102: 106.

Manufactured by: Bimeda-MTC Animal Health Inc., Cambridge ON, N3C 2W4

8XYL003A

CPN: 1194092.6