Alfaxan 10 Mg/Ml Solution For Injection For Dogs And Cats

Revised: September 2016

AN: 00649/2016



ALFAXAN 10 mg/ml solution for injection for dogs and cats


Active substance: alfaxalone 10 mg/ml

For the full list of excipients, see section 6.1.


Solution for injection

Clear colourless solution


4.1 Target species

Dogs and cats

4.2 Indications for use, specifying the target species

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

4.3 Contraindications

Do not use in combination with other intravenous anaesthetic agents.

4.4 Special warnings

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.

4.5 Special precautions for use

(i) Special precautions for use in animals

The analgesic properties of alfaxalone are limited, therefore appropriate peri-operative analgesia should be provided in cases where procedures are anticipated to be painful.

The safety of the veterinary medicinal product in animals less than 12 weeks of age has not been demonstrated.

Transient post induction apnoea frequently occurs, particularly in dogs – see section 4.6 for details. 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 the veterinary medicinal product by slow intravenous injection and not as a rapid dose.

Especially when using higher doses of the veterinary medicinal product, 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. In cats or dogs with renal insufficiency, doses for induction and maintenance may require reduction.

As with all general anaesthetic agents:

Psychomotor excitement may be encountered in a minority of dogs and cats recovering from anaesthesia with the veterinary medicinal product. 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.

(ii) Special precautions to be taken by the person administering the veterinary medicinal product to animals

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.

4.6 Adverse reactions (frequency and seriousness)

In clinical studies using the veterinary medicinal product, 44% of dogs and 19% of cats experienced post induction apnoea, which was defined as the cessation of breathing for 30 seconds or more. The mean duration of apnoea in these animals was 100 seconds in dogs and 60 seconds in cats. Endotracheal intubation and oxygen supplementation should therefore be employed.

4.7 Use during pregnancy, lactation or lay

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. The product has been safely used in dogs for the induction of anaesthesia prior to delivery of puppies by caesarean section. In these studies, dogs were not premedicated, a dose of 1-2 mg/kg was drawn up (i.e. slightly lower than the usual 3 mg/kg dose, see section 4.9) and the product was administered as recommended, to effect.

4.8 Interaction with other medicinal products and other forms of interaction

The veterinary medicinal product has been demonstrated to be safe when used in combination with the following premedicant classes:

Drug Class



acepromazine maleate

Anticholinergic agents

atropine sulfate


diazepam, midazolam hydrochloride,

Alpha-2-adrenoceptor agonists

xylazine hydrochloride, medetomidine hydrochloride


methadone, morphine sulfate, butorphanol tartrate, buprenorphine hydrochloride


carprofen, meloxicam

The concomitant use of other CNS depressants should be expected to potentiate the depressant effects of the veterinary medicinal product, necessitating cessation of further administration of the veterinary medicinal product when the required depth of anaesthesia has been reached.

The use of one premedicant or a combination of premedicants often reduces the dose of the veterinary medicinal product 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 the veterinary medicinal product.

Refer to section 4.3.

4.9 Amounts to be administered and administration route

Induction of anaesthesia:

The induction dose of the veterinary medicinal product 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:

















The dosing syringe should be prepared to contain the above dose. 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. The necessary injection rate can be achieved by administration of one quarter (¼) of the calculated dose every 15 seconds, so 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.

Maintenance of anaesthesia:

Following induction of anaesthesia with the veterinary medicinal product, the animal may be intubated and maintained on the veterinary medicinal product or an inhalation anaesthetic agent. Maintenance doses of the veterinary medicinal product may be given as supplemental boluses or as constant rate infusion. The veterinary medicinal product 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.

Dosing recommendations for maintenance of anaesthesia are as follows:







Dose for constant rate infusion


8 - 9

6 - 7

10 - 11

7 - 8


0.13 - 0.15

0.10 - 0.12

0.16 - 0.18

0.11 - 0.13


0.013 - 0.015

0.010 - 0.012

0.016 - 0.018

0.011 - 0.013

Bolus dose for each 10 minutes maintenance


1.3 - 1.5

1.0 - 1.2

1.6 - 1.8

1.1 - 1.3


0.13 - 0.15

0.10 - 0.12

0.16 - 0.18

0.11 - 0.13

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

4.10 Overdose (symptoms, emergency procedures, antidotes), if necessary

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 not life threatening and is compensated for by changes in heart rate. These animals can be treated solely by intermittent positive pressure ventilation (if required) with either room air or, preferably, oxygen. Recovery is rapid with no residual effects.

4.11 Withdrawal periods

Not applicable.


Pharmacotherapeutic group: other general anaesthetics, alfaxalone.

ATCvet code: QN01AX05.

5.1 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 GABAAcell surface receptors.

5.2 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 vitro cat and dog hepatocyte studies show that alfaxalone experiences both Phase I (cytochrome P450 dependent) and Phase II (conjugation dependent) metabolism. Both cats and dogs form the same five (5) Phase I alfaxalone metabolites. The Phase II metabolites observed in cats are alfaxalone sulphate and alfaxalone glucuronide, while alfaxalone glucuronide is observed in the dog.

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.

In both dogs and cats the elimination of alfaxalone demonstrates non-linear (dose-dependent) pharmacokinetics.

Alfaxalone metabolites are likely to be eliminated from the dog and cat by the hepatic/faecal and renal routes, similar to other species.


6.1 List of excipients


Sodium Chloride

Disodium Phosphate Anhydrous

Potassium Dihydrogen Phosphate

Sodium Hydroxide (for pH adjustment)

Hydrochloric Acid, Concentrated (for pH adjustment)

Water for Injections

6.2 Incompatibilities

In the absence of compatibility studies, the veterinary medicinal product must not be mixed with other veterinary medicinal products.

6.3 Shelf life

Shelf life of the veterinary medicinal product as packaged for sale: 3 years.

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

6.4. Special precautions for storage

Do not freeze. Keep the container in the outer carton.

6.5 Nature and composition of immediate packaging

Cardboard box with one glass vial of 10 ml with a bromobutyl rubber stopper and aluminium cap.

6.6 Special precautions for the disposal of unused veterinary medicinal product or waste materials derived from the use of such products

Any unused veterinary medicinal product or waste material derived from such veterinary medicinal product should be disposed of in accordance with local requirements.


Jurox (UK) Limited

Second Floor

Richmond House

105 High Street


West Sussex

RH10 1DD

United Kingdom


Vm: 25296/4000


23 November 2006


September 2016

21 September 2016

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