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Alfaxan (Canada)

This page contains information on Alfaxan for veterinary use.
The information provided typically includes the following:
  • Alfaxan Indications
  • Warnings and cautions for Alfaxan
  • Direction and dosage information for Alfaxan

Alfaxan

This treatment applies to the following species:
Manufacturer: Central Sales

Alfaxalone BP 10 mg/ml

For veterinary use only

Description

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

Alfaxan Indications

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

Alfaxan Dosage And Administration

Induction of Anaesthesia:

The induction dose of Alfaxan 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 anaesthesia. Dosing recommendations for induction of anaesthesia are as follows:

 

DOGS

CATS

Un-premedicated

Premedicated

Un-premedicated

Premedicated

mg/kg

3

2

5

5

ml/kg

0.3

0.2

0.5

0.5

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 anaesthesia is sufficient for endotracheal intubation, or until the entire dose has been administered.

Maintenance of anaesthesia:

Following induction of anaesthesia with Alfaxan, the animal may be intubated and maintained on Alfaxan or an inhalation anaesthetic agent. Maintenance doses of Alfaxan may be given as supplemental boluses or as constant rate infusion. Alfaxan 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 anaesthesia are based on data taken from controlled laboratory and field studies and represent the average amount of drug required to provide maintenance anaesthesia for a dog or cat. However the actual dose will be based on the response of the individual patient.

Alfaxan doses suggested for maintenance of anaesthesia are as follows:

 

DOGS

CATS

Un-premedicated

Premedicated

Un-premedicated

Premedicated

Dose for constant rate infusion

mg/kg/hour

8 - 9

6 - 7

10 - 11

7 - 8

mg/kg/minute

0.13 - 0.15

0.10 - 0.12

0.16 - 0.18

0.11 - 0.13

ml/kg/minute

0.013 - 0.015

0.010 - 0.012

0.016 - 0.018

0.011 - 0.013

Bolus dose for each 10 minutes maintenance

mg/kg

1.3 - 1.5

1.0 - 1.2

1.6 - 1.8

1.1 - 1.3

ml/kg

0.13 - 0.15

0.10 - 0.12

0.16 - 0.18

0.11 - 0.13

Where maintenance of anaesthesia is with Alfaxan 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 injected subsequently to maintain the required level and duration of anaesthesia. In most cases the average duration of recovery when using Alfaxan for maintenance will be longer than if using an inhalant gas as a maintenance agent.

Lnteraction With Other Veterinary Medicinal Products

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

Drug Class

Examples

Phenothiazines

acepromazine maleate

Anticholinergic agents

atropine sulfate

Benzodiazepines

diazepam, midazolam hydrochloride

Alpha-2-adrenoceptor agonists

xylazine hydrochloride, medetomidine hydrochloride

Opiates

methadone, morphine sulfate, butorphanol tartrate, buprenorphine hydrochloride

NSAIDs

carprofen, meloxicam

The use of one premedicant or a combination of premedicants often reduces the dose of Alfaxan required. Premedication with alpha-2-adrenoceptor agonists such as xylazine and medetomidine can markedly increase the duration of anaesthesia 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 anaesthesia in some patients may be sub-optimal. Benzodiazepines may be used safely and effectively in combination with other premedicants and Alfaxan.

Contraindications

Do not use in combination with other intravenous anaesthetic 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 anaesthetic.

● 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 anaesthesia, the use of an endotracheal tube is recommended to maintain airway patency.

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

● Respiratory embarrassment may occur - ventilation of the lungs with oxygen should be considered if haemoglobin saturation with oxygen (SpO2%), as measured by a pulse oximeter, falls below 90% or if apnoea 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, necessitating cessation of further administration of Alfaxan when the required depth of anaesthesia has been reached.

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

The safety of Alfaxan 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 apnoea 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 apnoea, 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, a dose-dependent respiratory depression may occur. Oxygen and/or intermittent positive pressure ventilation should be administered to counteract the threatening hypoxaemia/hypercapnea. This should be particularly important in risky anaesthetic cases and whenever the anaesthesia is to be carried out for a longer period of time.

In both dogs and cats, the dose interval for maintenance of anaesthesia 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 anaesthesia. Post-anaesthetic 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 (apnoea 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 apnoea 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.

DOGS

CATS

Apnoea

Apnoea

Respiratory arrest

Respiratory arrest

Cardiac arrest

Cardiac arrest

Bradycardia

Cyanosis

Seizures

Seizures

Prolonged anaesthesia

Prolonged anaesthesia

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 apnoea 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 anaesthetic. The primary mechanism for the anaesthetic action of alfaxalone is modulation of neuronal cell membrane chloride ion transport, induced by binding of alfaxalone to GABAA 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

Keep the vial in the outer carton. Store at controlled room temperature (15°C to 30°C). Do not freeze.

This product does not contain an antimicrobial preservative. Any solution remaining in the vial following withdrawal of the required dose should be discarded.

HOW SUPPLIED

Supplied as a 10 mL single dose vial.

Manufactured by: Jurox Pty Limited, 85 Gardiner Street, Rutherford NSW 2320 Australia

Distributed by: Central Sales Limited, 1/14 Regan Road, Brampton, ON L7A 1B9, Canada

DIN: 02324040

409981 V01

NAC No.: 1170030.0

CENTRAL SALES LTD.
14 REGAN RD., UNIT # 1, BRAMPTON, ON, L7A 1B9
Telephone:   905-840-0800
Order Desk:   800-387-2522
Local Fax:   905-840-1309
Toll-Free Fax:   888-437-9999
Website:   www.centralsales.ca
Email:   customerservice@centralsales.ca
Every effort has been made to ensure the accuracy of the Alfaxan information published above. However, it remains the responsibility of the readers to familiarize themselves with the product information contained on the Canadian product label or package insert.

Copyright © 2016 North American Compendiums. Updated: 2016-10-31

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