X-Ject SA

Company: Henry Schein^® Animal Health

Xylazine

20 mg/mL

Sedative and Analgesic

For Use in Dogs and Cats Only

Description:

X-Ject SA (xylazine) is supplied in 20 mL multiple-dose vials as a sterile solution.

Each mL contains 20 mg xylazine (base equivalent), 0.9 mg methylparaben, 0.1 mg propylparaben, water for injection; citric acid and sodium citrate for pH adjustment to 5.5 ± 0.3.

Active Ingredients:

Xylazine Hydrochloride 2.3% (Equivalent to 2% base)

INERT INGREDIENTS: 97.7%

X-Ject SA Caution:

Federal law restricts this drug to use by or on the order of a licensed veterinarian.

Pharmacology:

X-Ject SA (xylazine), a non-narcotic compound, is a sedative and analgesic as well as muscle relaxant. Its sedative and analgesic activity is related to central nervous system depression. Its muscle-relaxant effect is based upon inhibition of the intraneural transmission of impulses in the central nervous system. The principal pharmacological activities develop within 10 to 15 minutes after intramuscular or subcutaneous injection, and within 3 to 5 minutes following intravenous administration.

A sleeplike state, the depth of which is dose-dependent, is usually maintained for 1 to 2 hours, while analgesia lasts from 15 to 30 minutes. The centrally-acting muscle relaxant effect causes relaxation of the skeletal musculature complementing sedation and analgesia.

In animals under the influence of X-Ject SA (xylazine), the respiratory rate is reduced as in natural sleep. Following treatment with X-Ject SA (xylazine), the heart rate is decreased and a transient change in the conductivity of the cardiac muscle may occur as evidenced by a partial atrioventricular block. This resembles the atrioventricular block often observed in apparently normal animals.¹ Intravenous administration of X-Ject SA (xylazine) causes a transient rise in blood pressure, followed by a slight decrease.

X-Ject SA (xylazine) should be used in dogs and cats when it is desirable to produce a state of sedation accompanied by a shorter period of analgesia. X-Ject SA (xylazine) has been used successfully as follows:

1. Diagnostic procedures - examination of mouth and ears, abdominal palpation, rectal palpation, vaginal examination, catheterization of the bladder and radiographic examinations.

2. Orthopedic procedures, such as application of casting materials and splints.

3. Dental procedures.

4. Minor surgical procedures of short duration such as debridement, removal of cutaneous neoplasms and suturing of lacerations.

5. To calm and facilitate restraint of fractious animals.

6. Therapeutic medication for sedation and relief of pain following injury or surgery.

7. Major surgical procedures:

a. When used as a preanesthetic to general anesthesia.

b. When used in conjunction with local anesthetics.

Dosage and Administration

1. Dosage Intravenously - 0.5 mL/20 lbs body weight (0.5 mg/lb).

Intramuscularly or Subcutaneously - 1 mL/20 lbs body weight (1 mg/lb).

In large dogs (over 50 lbs), a dosage of 0.5 mg/lb administered intramuscularly may provide sufficient sedation and/or analgesia for most procedures.

Since vomiting may occur (see Side Effects), fasting for 6-24 hours prior to the use of X-Ject SA (xylazine) may reduce the incidence; the I.V. route results in the least vomiting.

Following injection of X-Ject SA (xylazine), the animal should be allowed to rest quietly until the full effect has been reached.

These dosages produce sedation which is usually maintained for 1 to 2 hours and analgesia which lasts for 15 to 30 minutes.

2. Preanesthetic to Local Anesthesia:

X-JECT SA (xylazine) at the recommended dosages can be used in conjunction with local anesthetics, such as procaine or lidocaine.

3. Preanesthetic to General Anesthesia: X-Ject SA (xylazine), at the recommended dosage rates, produces an additive effect to central nervous system depressants such as pentobarbital sodium, thiopental sodium and thiamylal sodium. Therefore, the dosage of such compounds should be reduced and administered to the desired effect. In general, 1/3 to 1/2 of the calculated dosage of the barbiturates will be needed to produce a surgical plane of anesthesia. Post-anesthetic or emergence excitement has not been observed in animals preanesthetized with X-Ject SA (xylazine).

X-Ject SA (xylazine) has been used successfully as a pre-anesthetic agent for pentobarbital sodium, thiopental sodium, thiamylal sodium, nitrous oxide, ether, halothane and methoxyflurane anesthesia.

Side Effects:

Emesis occurs occasionally in dogs, and frequently in cats, soon after the administration of X-Ject SA (xylazine), but before clinical sedation is evident. When observed, emesis usually occurs only a single time, after which there is no further emetic effect. The use of antiemetics may delay this phenomenon. The occurrence of emesis may be considered a desirable effect when X-Ject SA (xylazine) is administered as a preanesthetic to general anesthesia.

X-Ject SA (xylazine) used at the recommended dosage levels may occasionally cause slight muscle tremors, bradycardia with partial A-V heart block and a reduced respiratory rate. Should excessive respiratory depression occur following the use of X-Ject SA (xylazine), administer respiratory stimulants and provide artificial respiration.

Movement in response to sharp auditory stimuli may be observed.

Increased urination may occur in cats following the use of X-Ject SA (xylazine).

Precautions:

Clinical results with xylazine have not revealed any detrimental effects when the compound is administered to pregnant dogs or cats. However, until more definitive studies are completed, X-Ject SA (xylazine) is not recommended for use in these animals.

Careful consideration should be given before administering to dogs or cats with significantly depressed respiration, severe pathologic heart disease, advanced liver or kidney disease, severe endotoxic or traumatic shock and stress conditions such as extreme heat, cold or fatigue.

Analgesic effect is variable, and depth should be carefully assayed prior to surgical/clinical procedures. In spite of sedation, the practitioner and handlers should proceed with caution since defense reactions may not be diminished.

Do not use X-Ject SA (xylazine) in conjunction with tranquilizers.

Since an additive effect results from the use of X-Ject SA (xylazine) and the barbiturate compounds, it should be used with caution with these central nervous system depressants. Products known to produce respiratory depression or apnea, such as thiamylal sodium, should be given at a reduced dosage and, when injected intravenously, should be administered slowly.

When intravenous administration is desired, avoid perivascular injection in order to achieve the desired effect. Studies have shown negligible evidence of tissue irritation, however, following perivascular injection of xylazine.

Bradycardia and an arrhythmia in the form of incomplete atrioventricular block have been reported following xylazine administration. Although clinically the importance of this effect is questioned, a standard dose of atropine given prior to or following X-Ject SA (xylazine) will greatly decrease the incidence.

While sedation usually lasts from 1 to 2 hours, recovery periods in excess of 4 to 5 hours have been reported in both dogs and cats.

Safety:

X-Ject SA (xylazine) is tolerated in dogs and cats at 10 times the recommended dose. However, doses of this magnitude produce muscle tremors, emesis and long periods of sedation.

Warning:

The drug is for use in dogs and cats only.

How Supplied:

X-Ject SA (xylazine) is available in 20 mL multiple dose vials.

References

¹Detweiler, D.K., Patterson, D.F., Luginbuhl, H., Rhodes, W.H., Buchanan, J.W., Knight, D.H., Hill, J.D.: Diseases of the Cardiovascular System in Canine Medine, Edited by E.J. Catcott, American Veterinary Publications, Inc., Santa Barbara, California and Wheaton, Illinois, (1968), 589-679.

ANADA 200-184, Approved by FDA

CPN: 10823002