Alfaxan Multidose (Canada)

Alfaxalone Injection 10 mg/ml

Brief Summary of Prescribing Information

N.B. For full prescribing information go to www.jurox.ca

For veterinary use only

Description

Sterile intravenous general anaesthetic solution for dogs and cats, with its mode of action as a GABA_A receptor blocker.

Alfaxan Multidose Indications

As an induction agent prior to inhalation anesthesia in dogs and cats. As a sole anesthetic agent for the induction and maintenance of anesthesia for the performance of examination or surgical procedures in dogs and cats.

Alfaxan Multidose Dosage And Administration

Induction Of Anesthesia

The induction dose of Alfaxan^® Multidose is based on data taken from controlled laboratory and field studies and is the amount of drug required for 9 of 10 dogs or cats (i.e. 90th percentile) to be successfully induced for anesthesia.

Dosing recommendations for induction of anesthesia are as follows:

The dosing syringe should be prepared to contain the above dose. The rate of intravenous injection should be such that the total dose, if required, would be administered over the first 60 seconds. If, 60 seconds after complete delivery of this first induction dose, intubation is still not possible, one further similar dose may be administered to effect. The necessary injection rate can be achieved by administration of one quarter (1/4) of the calculated dose every 15 seconds. Administration should continue until the clinician is satisfied that the depth of anesthesia is sufficient for endotracheal intubation, or until the entire dose has been administered.

Maintenance Of Anesthesia

Following induction of anesthesia with Alfaxan^® Multidose, the animal may be intubated and maintained on Alfaxan^® Multidose or an inhalation anesthetic agent. Maintenance doses of Alfaxan^® Multidose may be given as supplemental boluses or as constant rate infusion. Alfaxan^® Multidose has been used safely and effectively in both dogs and cats for procedures lasting for up to one hour. The following doses suggested for maintenance of anesthesia are based on data taken from controlled laboratory and field studies and represent the average amount of drug required to provide maintenance anesthesia for a dog or cat. However the actual dose will be based on the response of the individual patient.

Alfaxan^® Multidose doses suggested for maintenance of anesthesia are as follows:

Where maintenance of anesthesia is with Alfaxan^® Multidose for procedures lasting more than 5 to 10 minutes, a butterfly needle or catheter can be left in the vein, and small amounts of Alfaxan^® Multidose, injected subsequently to maintain the required level and duration of anesthesia. In most cases the average duration of recovery when using Alfaxan^® Multidose for maintenance will be longer than if using an inhalant gas as a maintenance agent.

Lnteraction With Other Veterinary Medicinal Products

Alfaxan^® Multidose has been demonstrated to be safe when used in combination with the following premedicant classes:

The use of one premedicant or a combination of premedicants often reduces the dose of Alfaxan^® Multidose required. Premedication with alpha-2-adrenoceptor agonists such as xylazine and medetomidine can markedly increase the duration of anesthesia in a dose dependent fashion. In order to shorten recovery periods it may be desirable to reverse the actions of these premedicants. Benzodiazepines should not be used as sole premedicants in dogs and cats as the quality of anesthesia in some patients may be sub-optimal. Benzodiazepines may be used safely and effectively in combination with other premedicants and Alfaxan^® Multidose.

Contraindications

Do not use in combination with other intravenous anesthetic agents. In the absence of compatibility studies, the veterinary medicinal product must not be mixed with other veterinary medicinal products.

Cautlons

As with all general anaesthetic agents:

● It is advisable to ensure that the patient has been fasted before receiving the anesthetic.

● Additional monitoring is advised and particular attention should be paid to respiratory parameters in aged animals, or in cases where there may be additional physiological stress imposed by pre-existing pathology, shock or caesarean section.

● Following induction of anesthesia, the use of an endotracheal tube is recommended to maintain airway patency.

● It is advisable to administer supplemental oxygen during maintenance of anesthesia.

● Respiratory embarrassment may occur - ventilation of the lungs with oxygen should be considered if hemoglobin saturation with oxygen (SpO₂%), as measured by a pulse oximeter, falls below 90% or if apnea persists for longer than 60 seconds.

● If cardiac arrhythmias are detected, attention to respiratory ventilation with oxygen is the first priority followed by appropriate cardiac therapy or intervention.

The concomitant use of other CNS depressants should be expected to potentiate the depressant effects of Alfaxan^® Multidose, necessitating cessation of further administration of Alfaxan^® Multidose when the required depth of anesthesia has been reached.

Appropriate analgesia should be provided in cases where procedures are anticipated to be painful.

The safety of Alfaxan^® Multidose, in animals less than 12 weeks of age has not been demonstrated.

During recovery, it is preferable that animals are not handled or disturbed. This may lead to paddling, minor muscle twitching or movements that are more violent. While better avoided, such reactions are clinically insignificant.

Transient post induction apnea frequently occurs, particularly in dogs. In such cases, endotracheal intubation and oxygen supplementation should be employed. Facilities for intermittent positive pressure ventilation should be available. In order to minimise the possibility of apnea, administer by slow intravenous injection (over a period of approximately 60 seconds) and not as a rapid dose.

Especially when using higher doses of Alfaxan^® Multidose, a dose-dependent respiratory depression may occur. Oxygen and/or intermittent positive pressure ventilation should be administered to counteract the threatening hypoxemia/hypercapnea. This should be particularly important in risky anesthetic cases and whenever the anesthesia is to be carried out for a longer period of time.

In both dogs and cats, the dose interval for maintenance of anesthesia by intermittent bolus administration may require lengthening by more than 20%, or the maintenance dose by intravenous infusion may require reduction by more than 20%, when hepatic blood flow is severely diminished or hepatocellular injury is severe.

Psychomotor excitement may be encountered in a minority of dogs and cats recovering from Alfaxan^® Multidose anesthesia. Post-anesthetic recovery should thus take place in appropriate facilities and under sufficient supervision. Use of a benzodiazepine as the sole premedicant may increase the probability of psychomotor excitement.

Use during pregnancy and lactation:

The safety of the veterinary medicinal product has not been established in cases where pregnancy is to be continued or during lactation. Its effects upon fertility have not been evaluated. However, studies using alfaxalone in pregnant mice, rats and rabbits have demonstrated no deleterious effects on gestation of the treated animals, or on the reproductive performance of their offspring. The product should be used in pregnant animals according to the risk-benefit assessment performed by the veterinarian.

Warnings

If the product comes into contact with the eyes or skin, wash off immediately with water. In case of accidental self injection seek immediate medical attention and show the product literature to the doctor. Keep out of reach of children.

Adverse Reactions

In dogs, respiratory depression (apnea and bradypnea) can be very common, while hypoxia can be common. Cardiovascular effects (either increased or decreased heart rate, and increased or decreased blood pressure) can be very common.

In cats, respiratory depression in the form of apnea can be very common, while bradypnea and hypoxia may be common. Cardiovascular effects (either increased or decreased heart rate, and increased or decreased blood pressure) can be very common.

Hypothermia can be experienced very commonly in dogs, and commonly in cats. Emesis is uncommon in both species.

Post-market Adverse Drug Reactions

Although all adverse reactions are not reported, the following adverse reaction information is based on voluntary post-approval drug experience reporting. It is generally recognised that this method of reporting results in significant under-reporting of adverse drug reactions. It should be noted that suspected adverse drug reactions listed here reflect reporting and not causality. The categories of adverse reactions are listed in decreasing order of frequency by body system.

Overdose

Acute tolerance to overdose has been demonstrated up to 10 times the recommended dose of 2 mg/kg in the dog (i.e. up to 20 mg/kg) and up to 5 times the recommended dose of 5 mg/kg in the cat (i.e. up to 25 mg/kg). For both dogs and cats, these excessive doses delivered over 60 seconds cause apnea and a temporary decrease in mean arterial blood pressure. The decrease in blood pressure is typically compensated for by changes in heart rate. When hypotension persists, these animals should be treated by intermittent positive pressure ventilation with room air or oxygen and, if required, with fluid therapy. Recovery is usually rapid.

Clinical Pharmacology

Pharmacodynamic properties: Alfaxalone (3-α-hydroxy-5-α-pregnane-11,20-dione) is a neuroactive steroid molecule with properties of a general anesthetic. The primary mechanism for the anesthetic action of alfaxalone is modulation of neuronal cell membrane chloride ion transport, induced by binding of alfaxalone to GABA_A cell surface receptors. Alfaxalone has limited analgesic properties at clinical doses.

Pharmacokinetic particulars: The volume of distribution after a single injection of clinical doses of 2 and 5 mg/kg bw of alfaxalone in dogs and cats is 2.4 L/kg and 1.8 L/kg, respectively. In cats, the mean terminal plasma elimination half-life (t1/2) for alfaxalone is approximately 45 minutes for a 5 mg/kg dose. Mean plasma clearance for a 5 mg/kg dose is 25.1 ± 7.6 ml/kg/min. In dogs, the mean terminal plasma elimination half-life (t1/2) for alfaxalone is approximately 25 minutes for a 2 mg/kg dose. Plasma clearance for a 2 mg/kg dose is 59.4 ± 12.9 ml/kg/min. Alfaxalone metabolites are likely to be eliminated from the dog and cat by the hepatic/faecal and renal routes, similar to other species.

Storage

Store at controlled room temperature (15°C to 30°C).

Shelf life after first opening the container: 28 days.

HOW SUPPLIED

Supplied as a 10 ml or 20 ml multi-dose glass vial.

Manufactured by:

Jurox Pty Limited, 85 Gardiner Street, Rutherford NSW 2320 Australia

DIN: 02468670

Master Distributor For Canada

Central Sales Limited, 1-14 Regan Road, Brampton, Ontario, L7A 1B9

Customer Service 1-800-387-2522

CAN-Multidose Prescribing Info-Jun 2020

CPN: 2065000.0