Alfaxan Multidose
Active substance
ATC code
Species
Dogs, cats and pet rabbits
Indications
As an induction agent prior to inhalation anaesthesia in dogs, cats and pet rabbits.
As a sole anaesthetic agent for the induction and maintenance of anaesthesia for the performance of examination or surgical procedures in dogs and cats.
Dose to be administered and administration route
For intravenous use
Induction of anaesthesia (dogs, cats and pet rabbits):
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 patients (i.e. 90th percentile) to be successfully induced for anaesthesia.
Dosing recommendations for induction of anaesthesia are as follows:
|
DOGS |
CATS |
RABBITS |
||||
|
Unpremedicated |
Premedicated |
Unpremedicated |
Premedicated |
Unpremedicated |
Premedicated |
|
|
mg/kg |
3 |
2 |
5 |
5 |
5 |
4 |
|
ml/kg |
0.3 |
0.2 |
0.5 |
0.5 |
0.5 |
0.4 |
In dogs, cats and rabbits, an intravenous catheter should be used to administer the product (please refer to sections 4.5i and 4.6).
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 (dogs and cats):
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 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:
|
DOGS |
CATS |
|||
|
Unpremedicated |
Premedicated |
Unpremedicated |
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 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.
Adverse reactions
In clinical studies using the veterinary medicinal product, post induction apnoea, which was defined as the cessation of breathing for 30 seconds or more, was very common in dogs and cats, and common in rabbits.
Based on post marketing safety experience, neurological signs (convulsions, myoclonus, tremor, prolonged anaesthesia), cardio respiratory signs (cardiac arrests, bradycardia, bradypnea) and behavioural signs (hyperactivity, vocalisation) have been reported very rarely (.
The frequency of adverse reactions is defined using the following convention:
- very common (more than 1 in 10 animals treated displaying adverse reaction(s))
- common (more than 1 but less than 10 animals in 100 animals treated)
- uncommon (more than 1 but less than 10 animals in 1,000 animals treated)
- rare (more than 1 but less than 10 animals in 10,000 animals treated)
- very rare (less than 1 animal in 10,000 animals treated, including isolated reports).
The mean duration of apnoea in these animals was 100 seconds in dogs, 60 seconds in cats and 53 seconds in rabbits. Endotracheal intubation and oxygen supplementation should therefore be employed.
In rabbits, defensive reactions (such as head-shaking, ear flicking and backing away) are commonly observed during intravenous (marginal ear vein) administration and, therefore, administration of the product via a pre-placed catheter in the marginal ear vein is recommended. Premedication may also prevent these reactions. In a field study, these reactions were not observed when rabbits had been premedicated with medetomidine in combination with either butorphanol or buprenorphine.
