Alfaxalone (alfaxan) use in cats

Re: Alfaxalone (alfaxan) use in cats

Hannah Wynne Richards — Tue, 30 Jun 2009 13:44:40 GMT

I love alfaxan and would'nt go back to propofol. I usually premed with vetergesic 0.03 ml/kg and 2 mgs/ml acp at 0.025 ml /kg wait 45 mins induce with alfaxan intubate and maintain on iso I am very fussy about both op theatre and recovery room being kept warm. This is for standard ops spays castrations in both dogs and cats Use NSAID for all routine ops as well. Obviously the premed is altered in more painful, higher risk procedures, but again I would always induce with alfaxan

Wynne

Re: Alfaxalone (alfaxan) use in cats

Rajat — Fri, 26 Jun 2009 19:30:17 GMT

Hi Malcolm,

Old talk and all I know and I hope your slow recovery issue has been sorted out...we have a cool Xray room and we really have to watch temps there as patients get cold very quickly!

Just wanted to say 0.1mg/kg morphine sounds a bit on the lower side...have you tried to go any higher? I tend to use 0.3mg/kg routinely for bitch spays, I know of a few people in Unis who do the same but no clue as to what everyone else here uses! Also started using Alfaxan recently and love it, bit weird how it has a slower onset cf propofol in the beginning but got used to it and love the fact it doesnt affect CV parameters much... a cheaper version of Etomidate!

Re: Alfaxalone (alfaxan) use in cats

james hunt — Mon, 01 Jun 2009 13:56:25 GMT

Hi Malcolma

I Think Brad has covered everything I might have suggested - ACP is useful if no contraindications - can reduce MAC of volatile by about 30%, so would account for you finding you require much higher vapouriser settings.

Have you stopped the nitrous for any particular reason?

We don't have access to N2O in our clinic, so for intraoperative analgesia in bitch spays I find ketamine 0.5-1mg/Kg im on arrival in the op theatre appears to reduce autonomic responses to ligament manipulation. You can give IV but usually causes apnoea unless given slowly, if IM will usually continue spontaneous respiration. Having had ACP in premed will be beneficial in reducing any ketamine related delirium in recovery, though I dont find too much evidence of this. Other options are intraoperative opioids (fentanyl/alfentanyl/remi) but more likely to require ventilation support.

best wishes

james

Re: Alfaxalone (alfaxan) use in cats

Arlo Guthrie — Thu, 28 May 2009 09:34:22 GMT

[quote user="Malcolma"]Absolutely awesome reply[/quote]

Exactly what I was thinking! And thanks Malcolm for the kind comments about the site.

One way to keep in contact is to visit Brad's profile (click his name adjacent to the post) and invite him to become a VetSurgeon Colleague. That way, he'll be added to your personal list of contacts on the site.

Re: Alfaxalone (alfaxan) use in cats

Malcolma — Thu, 28 May 2009 05:34:42 GMT

Hi Brad

Absolutely awesome reply - thanks :) . I cant say how happy I am with this forum and info. As I dont usually have time or the other forums (eg online courses ) are so academically biased with very little practical application in a clinical setting. We have actually found that the online nursing courses are usually of more value for us.

Both of us here have joined this site and would recommend it to anyone. To have "normal" non judgemental people to discuss these issues with is fantastic

Anyway. I am very thankful for the ideas. I should have thought of the atropine blocking the cardiac response re aneastheric depth monitoring. Pretty obvious really.

We used lo dose acp (0.022mg /kg )+ 0.1mg/kg morphine + atropine (0.022mg/kg) today in the 20kg dogs plus normal induction dose of alfaxan + iso today and had a much better day. Also used local at the incision and testicles as mentioned for pain relief.

Smooth and short recovery time and smooth transition. Speys 2moro and will drop out the atropine.

It has been an interesting 2 weeks for us - (thought about taking up smoking at one point - ha ha) and it certainly has made us think far more closley about what we do. I think after years of doing the same you can certainly become complacent even though to know your regime is great.

I would like to keep in contact Brad if that is OK. My email is malcolm@vetz.co.nz

The small breed dog and infant puppy anaesthesia still interests me and I would think is an area that a lot of vets still worry about and have difficulty with at times esp speys. Speys even after many years are an area that are taken so lightly incl by the public(as they are not aware of the real procedure or possible complications esp adult bitch speys) and I would think that every vet has had a nightmare experince. Maybe small breed and neonate anaesthesia could be another forum topic and in particular the whole peritoneal/ ovarian ligament response. True, a function of aneasthetic depth but that response does seem to be exaggerated in the smaller breed? ?? Or maybe we just tend to have them too light beacuse we are concerned re their size etc. any thoughts in a new forum.

All the very best

Malcolm

Re: Alfaxalone (alfaxan) use in cats

Brad O'Hagan — Thu, 28 May 2009 02:18:45 GMT

This is my first use of this forum. I should declare my background at the outset - I work for Jurox Pty Ltd, in Australia, as the Veterinary Services Manager. We manufacture Alfaxan, which is now distributed in several countries by a number of companies. Despite this I will give you my best effort of being unbiased.

As has been stated, it would appear that you have made several changes all at once to your protocol. This makes it very difficult to be comparing anaesthetic experiences, and truthfully, as each patient is an individual, comparing apples with apples is very difficult even with all drugs, equipment and procedures kept the same. However I see some potential areas that may help you with your use of Alfaxan as an anaesthetic induction agent.

1. ACP is a very useful premedicant. I accept there are times when it shouldnt be used - certain CV problems, MDR1 mutant dogs etc, however I think that for most healthy patients it is an excellent premedicant choice. Remember that it is not just effective up to the point of induction but has a dose sparing effect on maintenance agents and is likely still imparting an influence in the recovery period, especially in short procedures. Even in our study of juvenille patients (which I am editing for submission at the moment) we used ACP as a premedicant. Dose is important obviously also.

2. Atropine - I think some of the comments made so far have addressed this, but by administering atropine you are removing an excellent indicator of changing anaesthetic depth, by telling the heart to run purely on its inherant rythmicity - ie by blocking parasympathetic effects. There is a place for atropine. Again, in the juvenile study we performed we used atropine as part of the premed regime, because neonatal animals are far more dependant on heart rate for maintenance of cardiac output, as they are less able to increase stroke volume or adjust peripheral resistance. However for most other anaestehtic events my opinion (for what it is worth) is that atropine/glycopyrrolate are better used as a response to bradycardia after all other causes of bradycardia have been investigated (pain, anaesthetic depth, etc)

3.Alfaxan induction - you note that you dilute the product. I understand why people have been doing this, but my own experience is that if you are quiet and calm at induction, you can deliver a quarter of the calculated induction requirement every fifteen seconds without any need for dilution. I can tell you that we only have stability data for dilution of Alfaxan in 0.9% saline, not sterile water or Hartmann's. These are on our list of things to look at, but for the time being if you are going to continue to dilute, please try to use saline. One thing that I think does happen is that many animals will become deeply sedated with Alfaxan relatively soon after starting injection. This can be misjudged as being anaesthetised and an ET tube can be placed perhaps prematurely. I realise that the product is more expensive than propofol, but when you are first getting used to using Alfaxan it is more sensible to administer the whole induction dose (2mg/kg for dogs, 5 mg/kg fopr cats) agent over 60 sec. Administering the whole dose at this rate is unlikely to give you apnoea (unless you are using an alpha2 agoinst for premedication) and will give you a little more time to place an ET tube and to transition the patient onto anaesthetic gas for maintenance. If apnoea does occur, ventilating (but not hyperventilating) the patient is all that is needed to be done - they should soon begin to spontaneously breath as the alfaxalone is redistributed from the CNS.

4. Anaesthetic Transition - transition is a period that is poorly understood in many veterinary practices and is often a reason for unusual anaesthetic maintenance period. It is important to understand that it takes 4 time constants to change the concentration of gas in the rebreathing circuit to a new setting on the vapouriser and that the time constant is equal to the volume of the circuit /fresh gas flow. We are effectively completing a second induction of the patient when we transition them to gaseous maintenance (1st = injectable agent, 2nd = gaseous agent). In practices that are used to using thiopentone or valium and ketamine for induction, when they go to using propofol or Alfaxan it is very common for there to be problem with transition. The time to recovery from the two short acting induction agents means that using the anaesthetic machine the way that you used to when you were using the other agents is likely to result in patients that dont transition to the maintenance period smoothly. As they become light they may hypoventilate and take up less gas and this makes things worse. You then start a roller coaster ride for your maintenance period and this gives an overall bad impression of the anaesthetic experience. The premeds that you use give you both a decrease in gas requirement for maintenance (and thereby shorten the transition time) and an increase in sleep period from the injectable agents (so a smoother transition period). - this is a nice review of low flow anaesthesia that also discusses transition and time constants well - http://www.clinicalwindow.net/cw_issue_14_article2.htm

5. Nitrous oxide blows gaseous agent into the patient and hastens the transition as well as providing possibly some analgesia, though some beleive this may not be the case. US specialists use little or no nitrous because of this beleif. I dont have a firm opinion on this myself

6. Cats and tracheal mucous - we hear about this from time to time and when we investigate there is often something else that has changed, such as ET tube cleaning (chlorhexidine is extremely irritant to the airways) or change in the local being used for laryngeal desensitization. This is not something that was recognised in any of our clinical trial work, but Vioxx was not recognised as a cause of heart disease in their trials either, so we are continuing to investigate all reports that we get about these things.

I hope that I have not been out of line in responding to this forum question. I am happy to stay out of discussions if moderators wish me to and I am also happy to discuss things directly with people who have questions.

Regards

Brad O'Hagan

Veterianry Services Manager, Jurox Pty Ltd

Re: Alfaxalone (alfaxan) use in cats

beldather — Wed, 27 May 2009 15:48:55 GMT

Please ignore the awful grammar and spelling, at end of day after horror on call night so aint to spritely in my thoughts

Re: Alfaxalone (alfaxan) use in cats

beldather — Wed, 27 May 2009 15:47:30 GMT

Hey Malcolm,

It sounds like you've made quite a few changes in a small amount of time so difficult to assess. Just as a point of info, when discussing anaesthetics its really usefull to supply drug concentrations used as is invaluable when trying to understand said protocols.
In regards to your dog spay, I truly think the lack of acp (or other sedative/tranquiliser) as you are soley relying on morphine (very dependent on dose and when given prior to surgery) and iso to maintain it. atropine in that mix looks to provide little if any benefit, bar making that heart pump it bit faster then it probably needs to (do you routinely measure BP?). Just as a thought (never really used atropine as a premed ) is it possible the use of atropine is masking the cardiovascular changes that your 'arnt' seeing with the pain response?
Any reason (since it looks like your in aus) that your using morphine over methadone?

In regards to your nitrous question, that is very good at adding additional analgesia so is likely keeping that ovarian ligament stimulus at bay very well, so without it you will need to account for more pain stimulus then previously. If your comfortable with using the nitrous I'd be reluctant to drop it.

In regards to your cat, I would have to say I've not noticed any change in mucous consistency b/n propofol and alfaxan, Ill ask one of my mates who is fairly involved in the studies to see if its been noted. Just as an aside what is the rest of the protocol you use with these cats, any other changes?

Regards

Blair

Re: Alfaxalone (alfaxan) use in cats

ms1083 — Tue, 26 May 2009 20:46:45 GMT

As nitrous is a potent analgesic and muscle relaxant could it have been providing extra analgesia meaning the plane of anaesthesia was able to be kept lower with regard to the isoflurane? It may be simply that your nurses are used to maintaining anaesthesia at a lighter level than that required without nitrous.

Re: Alfaxalone (alfaxan) use in cats

Malcolma — Tue, 26 May 2009 19:50:02 GMT

We dropped the acp out of the premed because of concerns re the younger patients (blood pressure etc) and on the recommendation of a referal practice. Its interesting that no-one uses atropine in the dogs. May be we can go back to acp/morphine.

Has anyone the same experiences with bitch speys at the point of ovarian manipulation re depth of anaeasthesia - When we used nitrous this was hardly ever an isssue.

Has anyone also noticed a difference in the incidence of endotracheal tube congestion with alfaxan vs propofol in the cats. We certainly have since we changed to using it exclusively in the cats 3 weeks ago.

Re: Alfaxalone (alfaxan) use in cats

ms1083 — Tue, 26 May 2009 13:32:52 GMT

What is your reason for using atropine? It is generally taken that there is no need for its routeine use now, it was more important with ether/halothane or to counteract bradycardia as a specific complication when and if if occurs. I would not think bitch spays waking up is to do with alfaxan - as it has a short half life, that stage of the anaesthetic is maintained by the inhalant gas, propofol has a short half life too so should really be no different than alfaxalone by that stage of surgery.

Try ACP & opioid, is unofficially considered the "normal" premed. Personally I like to decide the most sutible premed depending on clinical assesment of the patient so use a large array of different premeds. I have not yet had a dog wake up mid surgery after alfaxan use with any pre-med complication.

Re: Alfaxalone (alfaxan) use in cats

Malcolma — Tue, 26 May 2009 12:22:35 GMT

Hi Blair or anyone

We have just started using alfaxan after years of using propofol primarily due to a couple of problems we had with two 12 week old pups (that may have been due to acp- but unknown). I loved safan years ago and am generally liking alfaxan but are having one major problem that may again be premed related. We actually 100% dilute the alfaxan in saline prior to slow iv which eliminates the apnoea etc. Premed is morphine/ atropine without acp - we are talking dogs . Induce with alfaxan then on to iso.

We have found that they can be very light on the iso and need to go straght on to 2-3% to get them on a good plane after 10 minutes or so. This was never an issue with propofol but its a learning curve. (Probably need to increaase induction dose due to lack of acp?) The recovery times are short and great BUT our huge problem is bitch speys! (as always you say) . Nice smooth depth with eyes down, loose jaw tone etc and then touch the uterus or exteriorise an ovary and BANG the eyes are fully up and fully dilated - YEAH - very unnerving. But all the other parameters stay the same. I am talking- straight up with no warning. and then once we get to closure the eyes roll back down. I can only presume it is a pain response however all other parameters stay the same incl heart rate and resp rate. The nurses not surprisingly want to go back to propofol and acp .

Has anyone any idease re a protocol. May be add acp back in but we have been disinclined to do this esp with the young patients. After years of a charmed life with anaesthetics things are a bit nervy at present.

Re: Alfaxalone (alfaxan) use in cats

Stuart McArthur B Vet Med MRCVS — Mon, 09 Feb 2009 18:48:57 GMT

Hello all, This agent is wonderful in reptiles ( n= >100) and other exotics. The recent Vet Rec article about Rabbits under field conditions is also reassuring and helpful. Reptile induction time duration and recovery times all relaible and incremental dosing doesnt excessively extend this, which propofol seems to have problems with... affective IO - sorry my post isnt about cats! Great agent for the niche reptilian market though! Especially helpful in semiaquatic species that require rapid return to water. S

Re: Alfaxalone (alfaxan) use in cats

Evelyn Barbour-Hill — Fri, 06 Feb 2009 00:05:51 GMT

Another thing that kills cats in recovery is asphyxia due to mucus accumulation in the nasopharynx.

Patients in recovery kennels need to be observed and tended to as necessary. The larger practice should have a nurse on constant recovery-kennel duty (not simultaneously answering the phone, helping out in the dispensary.......... )

Re: Alfaxalone (alfaxan) use in cats

james hunt — Wed, 04 Feb 2009 23:19:00 GMT

Great to hear you have managed to improve recoveries by keeping the cats normothermic. I think your point about the nurses preference is actually very relevant - Dave Brodbelt found in his last survey of perianaesthetic mortality that the recovery period was when a significant number of cats died, therefore prolonged recoveries are to be avoided and this is one factor to keep in mind when selecting anaesthetic agents.

I know the manufacturers have licensed a dose rate of up to 5mg /Kg in cats- i have found i get nice smooth rapid inductions after ACP/opioid premed with 1-2mg/Kg and not found that recoveries have been prolonged compared to propofol.

PS it is recommended to give propofol over a couple of minutes as well to minimise cardiovascular depression and reduce total dose requirement.

Re: Alfaxalone (alfaxan) use in cats

ms1083 — Sun, 25 Jan 2009 17:44:25 GMT

Since my initial post I have used it more and on younger healthy animals as well as high risk animals. I have still had no problems in dogs.

Yes, the volumes are smaller but it has a slightly slower onset of action that propofol so therefore has to be given that bit slower (dose over 2 mins ideally), I wouldn't say that the volume to inject is an advantage as such. It is very easy to give it too fast and then find the animal is rather deep a min or so later (although it does have a x10 safety factor and the manufactures advise giving a set calculated dose, but still over 2 mins).

I have notied however, that cats, especially the older ones and especially dentals do get very cold very quickly compared to propofol and that seemed to be the reason for my slow recoveries. I think it must be due to it having less cardiovascular effects and maintaining peripheral circulation better than propofol-which is a good thing! Just highlightes how important temperature loss is for anaesthetic recoveries. Now we are really being very careful to monitor their temperature I have had no more slow recoveries.

Re: Alfaxalone (alfaxan) use in cats

ashjhwells — Sat, 24 Jan 2009 02:53:32 GMT

Neither of the practices I have worked at in my professional career have used Alfaxan (due either to partners' slight general resistance to change or to lingering fears over its relationship to the dreaded Saffan), but I have seen it used in dogs at a couple of practices on EMS placements.

One benefit that they cited was that smaller volumes required for induction cf. propofol meant that it is more convenient for anaesthetising large dogs - no need to swap syringes half-way through injecting - especially good when dealing with badly behaved Rotties etc!

On the cases that I saw Alfaxan used, the inductions and recoveries all seemed very smooth.

I gather it's also quite good for TIVA...

Re: Alfaxalone (alfaxan) use in cats

Christopher Tansley — Wed, 07 Jan 2009 13:22:21 GMT

I used alfaxan in New Zealand for about 3 months whilst locuming - was not actually very impressed in cats, fine in dogs, recoveries were very prolonged, no obvious advantage to cardiovascular or respiratory stability.

Was a smaller dose and over there was cheaper than propofol.

Much more expensive over here - no plans to change yet.

The safest anaesthetic agent is the one you are happiest using for now!

Re: Alfaxalone (alfaxan) use in cats

beldather — Thu, 27 Nov 2008 13:21:56 GMT

As an australian graduate it would have to be my favourite anaesthetic drug, alfaxan is pretty much the anaesthetic induction agent of choice in aus so most of us are quite used to using it.

In regards to long wake ups, I'd have to say I'm surprised, as it was always comparable if not sometimes quicker then propofol wakeups. Would have to wonder if premeds, iso levels, and procedure differences may be contributing. Also like propofol, titration by effect is pretty important with alfaxan as you will also get the apnoea if bolused.

With a good premed (then being methadone (0.5mg/kg) ACP(0.05mg/kg)) was usually using 1-1.5mg/kg of alfaxan for induction, also waiting a full 30-45sec on initial bolus before continuing titration would also help reduce required amount.

Alfaxan versus propofol, probably not a massive difference. so far alfaxan definitely appears to have a significantly less effect on the cardiovascular system then propofol (but thats relatively short lived anyhow), but probably the main reason I've always liked it is its typically half the volume required of propofol and it can be given IM as an induction agent, which used to be quite usefull for those feral cats. There is some tentative research atm which may indicate some analgesic effect, however I havn't placed much faith in that as its more theory then fact.

Probably the hardest thing to get over with alfaxan (as I continually try to get it at my current practice) is to get over the saffan reputation. Similar active ingrediants, very different carrier. Love it.

Regards

Blair Kennedy

Re: Alfaxalone (alfaxan) use in cats

Arlo Guthrie — Wed, 26 Nov 2008 08:26:10 GMT

[quote user="Evelyn Barbour-Hill"]You are awfully touchy about my little comment. [/quote]

Laughed - yes, I suppose I am a bit: a hazard of running a website for nurses for eight years! But there is a lot of evidence that many nurses feel (and are) undervalued, and I don't think that benefits anyone (least of all vets).

End of public service announcement. We can now return you to the discussion about Alfaxan ...

Re: Alfaxalone (alfaxan) use in cats

Evelyn Barbour-Hill — Tue, 25 Nov 2008 22:40:48 GMT

[quote user="Matthew Scotter"]When I have used it I have normally used an acepromazine/opioid intra muscular pre-med and given at least 30mins before induction, maintaince with isoflurane via E-T tube. On the whole I have used it in the more risky cases and they tend to be old cats for dentals. [/quote]

Back when I used Saffan, that premed would immensely prolong the waking-up time. Sometimes we used it for that very reason. Otherwise we used no premed.

Saffan had a lot of faults but I understood some of them were due to the vehicle.

I can't quite understand the comment about alfaxan recovery being more complete than propofol. I find the latter very quick and very complete. Maybe Liz Leece could enlarge upon this point?

Many of my procedures are prolonged, and I do many dental procedures in elderly cats, and with propofol induction and isoflurane maintenance I just don't see a problem. I'm not being arrogant, I'd be glad to change if something else was notably better in practical terms.

Evelyn

Re: Alfaxalone (alfaxan) use in cats

Evelyn Barbour-Hill — Tue, 25 Nov 2008 22:27:28 GMT

[quote user="Arlo Guthrie"]I'm going a bit off-topic here, but that reads as quite dismissive of nurses. Aren't they a second pair of eyes and ears, and aren't there therefore times when their opinions/observations ARE rightly a deciding factor?[/quote]

You are awfully touchy about my little comment.

If nurses are nursing they will constantly make useful observations which I value very much. Their opinions are not very important.

Re: Alfaxalone (alfaxan) use in cats

ms1083 — Tue, 25 Nov 2008 22:13:47 GMT

When I have used it I have normally used an acepromazine/opioid intra muscular pre-med and given at least 30mins before induction, maintaince with isoflurane via E-T tube. On the whole I have used it in the more risky cases and they tend to be old cats for dentals. I don't specifically remember any hypothermic problem and its the first thing the nurses tend to check. Obviously I have no idea if they would have taken the same amount of time to recover from propofol! Its certainly been a few cases, more than just a one off but sometimes recovery is similar to that of propofol (not convinced its quicker). Maybe they require less gas to maintain anaesthesia than we are using (about 2 on vaporiser)? I might try it on some cat spays and see what happens.

Re: Alfaxalone (alfaxan) use in cats

Phil Elkins — Tue, 25 Nov 2008 21:28:34 GMT

From Liz Leece:

Yeah...why am I still at work at this time?! I was just reading the alfaxan stuff with interest and it's great to see people are liking using it in dogs. I agree completely with that...I think you get nice cardiovascular parameters when you dose it to effect (usually less than the manufacturers' recommended dose rates) and very smooth recoveries. I get the impression that the recoveries are a bit more complete than with propofol and they recover very quickly. With respect to cats, I probably use it differently to people in practice as all my surgeries are longer procedures. So I premed followed by alfaxan for induction then intubation and inhalational anaesthesia. As long as the cats do not become hypothermic, recoveries are smooth and relatively rapid. I have not used the drug on its own in cats as I always opt for a more balanced anaesthetic approach. I am surprised that prolonged recoveries have been seen... it would be interesting to know if the drug was used on its own, if the cats did become hypothermic (if they did have a prolonged recovery, no doubt this was a major factor) and also if it happened with several cats. It has certainly been reported anecdotally that cats can have prolonged recoveries following all types of anaesthetic and we are trying to work out why this is...often it's the healthy ones where you least expect it! One of my residents is actually Australian and used it there for 5 years before she moved over here and she swears by alfaxalone.. I think it is like any anaesthetic drug...practice makes perfect (or as close to perfect as you can get)!

Liz Leece

Animal Health Trust

Re: Alfaxalone (alfaxan) use in cats

Ian Mostyn — Tue, 25 Nov 2008 12:21:15 GMT

They are a 2nd set of eyes and ears and certainly have the right to their own opinion but it is the vet who takes responsibility for the anaesthetic and ultimately must make their own decision. Saying that, if the nurses aren't happy with something, it is important to discuss their concerns and try to address them. The only time I get upset with my nurses during a GA is if they don't talk to me, tell me what is going on. Mind you, I am happy with propofol or the medetomindine/ketamine/butorphanol combo.