Premeds

RE: Premeds

David Mills — Fri, 06 Oct 2017 16:04:33 GMT

[quote user="Martin Atkinson"]So what is that protocol? You can't have a rigid protocol on this, a decision has to be made on a needs must basis and maybe you should trust assistants to make that judgement.[/quote]

It's an interesting question, and people seem to get very arsey about anaesthesia for some reason and "clinical freedom" whereas in other areas they're happy to follow protocols. One of the considerations in busy practices is throughput of patients and reduction of stress so protocols become somewhat necessary, such as triples/quads for young healthy spays/castrates. You can't simply have every vet doing something differently.

[quote user="Michael Woodhouse"]I don't really care if they want to reverse[/quote]

It makes me sad that most of the veterinary profession (and veterinary nurse teachers) misunderstand the basic pharmacology of alpha 2s and start wittering on about blood pressure. They're the safest anaesthetic around.

RE: Premeds

Martin Atkinson — Fri, 06 Oct 2017 15:28:49 GMT

[quote user="Michael Woodhouse"]The point is we have a protocol[/quote]So what is that protocol? You can't have a rigid protocol on this, a decision has to be made on a needs must basis and maybe you should trust assistants to make that judgement. My nurses are keen to reverse as they don't like monitoring comatose patients but if the're resting comfortably I tell them to leave them. If on the other hand they're having too prolonged a recovery or getting cold and/or need to go home PDS then I will reverse them. The lingering analgesia doesn't really reflect in that decision.

RE: Premeds

Michael Woodhouse — Fri, 06 Oct 2017 14:49:00 GMT

[quote user="Gillian Mostyn"]

I'm you actually mean 'discussing with your veterinary colleagues why you prefer not to give atipamezole.' Afterall, they will be responsible for any outcomes.

Unless, when you was an assistant, you was happy to be told by your boss how to conduct your anaesthetics?

[/quote]

Yes and no. I don't really care if they want to reverse (that's billed as extra so I make more money so good for me I suppose). The point is we have a protocol and I'm quite happy discussing or changing that if they come up with a viable alternative armed with some decent evidence.

They haven't thus far.....

RE: Premeds

Gillian Mostyn — Fri, 06 Oct 2017 13:48:23 GMT

[quote user="Michael Woodhouse"]Hardest part is stopping assistants reversing the alpha two as it provides excellent (particularly visceral) analgesia.[/quote]

I'm you actually mean 'discussing with your veterinary colleagues why you prefer not to give atipamezole.' Afterall, they will be responsible for any outcomes.

Unless, when you was an assistant, you was happy to be told by your boss how to conduct your anaesthetics?

RE: Premeds

Rob Loxley — Fri, 06 Oct 2017 13:17:20 GMT

[quote user="David Mills"]I encountered a practice recently giving premeds sc.[/quote]

There's certainly work on buprenorphine in cats to suggest i/m is significantly superior to s/c, and also some suggesting i/v is better still:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4895465/

"The authors do not recommend the SC route for buprenorphine in cats at clinical dosages (0.02 mg/kg). Moreover, IV injection has been associated with a much greater magnitude of antinociception, speed of onset, and duration of action when compared with other routes of administration.5, 16 Based on these results, buprenorphine should be given IV to cats whenever an IV catheter is in place. A dosage of 0.02 mg/kg has been reported,5, 16 and it is commonly used by the authors for acute pain in cats"

RE: Premeds

Eilidh Corr — Fri, 06 Oct 2017 12:56:32 GMT

I routinely give bup/dom premeds s/c and find them really reliable and predictable. Plus local in dental procedures and always with NSAIDs. I try to avoid painful IM injections in dogs I want to be calm and relaxed.

RE: Premeds

Michael Woodhouse — Fri, 06 Oct 2017 12:34:44 GMT

[quote user="David Mills"]Butorphanol is a terrible analgesic. Medetomidine is fabulous.

I encountered a practice recently giving premeds sc. Is this commonplace? [/quote]

We use butorphanol/medetomidine for practically everything and top up with methadone if needed. Hardest part is stopping assistants reversing the alpha two as it provides excellent (particularly visceral) analgesia. Give a colicing horse some xylazine if you don't believe me. I think the butorphanol antagonising pure agonists is kind of out with the arc, it's also quite short acting.

Always pre-med s/c, another reason why I don't like buprenorphine as I'd give that IM and its painful and requires more restraint. NSAID at time of pre-med also s/c.

DTK s/c works just fine also in cats.

RE: Premeds

Elisabeth Knappett — Fri, 06 Oct 2017 12:25:36 GMT

ACP/methadone routinely, switching out for alternatives for stroppy/hard to handle etc. Dose dependent on patient really. I use the 0.5mg/kg methadone dose for surgeries and nurses frequently comment how much more relaxed/easier to induce/more stable GA they have than with my colleague who uses 0.2mg/kg dose.

Always given IM and I tend to use the neck always - I seem to get no reactions (pain and swelling) and it's much simpler to do solo!

RE: Premeds

David Mills — Fri, 06 Oct 2017 10:53:50 GMT

[quote user="Catherine Jeanes"]Butorphanol is an agonist at kappa receptors and an antagonist at mu receptors. Any pure mu opioid given after butorphanol would not be as efficacious until the butorphanol wore off. [/quote]

Too simplistic. This would only obtain is the butorphanol occupied a large number of mu receptors, which it doesn't - the result is clinically insignificant. Bit like the dogma about bupe that has kicked around for decades.

[quote user="Neil Wheadon"]ersonally I like to try the S/C route as I just don't like injecting animals I/M due to restraint issues and it must hurt more (am I being reasonable here?) I don't find it makes a lot of difference aside needing to wait a little longer before induction.[/quote]

There's quite a bit of work around on the absorption and plasma levels of buprenorphine when given SC. It's basically very unreliable and unpredictable in terms of suration of action, time of onset and degree of analgesia - it is believed to provide at most only 70% of the analgesic action c.f. IM or IV (and average around 30-50%). It's something to do with becoming trapped in the SQ fat due to the pH of the drug or something.

Methadone and alpha 2s seem not to suffer this issue, but the time of onset is slower. Interestingly with methadone the time to peak serum levels is very similar when given IV or IM.

I suppose I just wouldn't trust SC. No doubt they get sleepy but whether that is just the ACP, sho knows. But it's the analgesia aspect and its apparent unreliability that worries me.

RE: Premeds

Martin Atkinson — Fri, 06 Oct 2017 10:25:21 GMT

[quote user="Neil Wheadon"]Personally I like to try the S/C route as I just don't like injecting animals I/M due to restraint issues and it must hurt more (am I being reasonable here?) I don't find it makes a lot of difference aside needing to wait a little longer before induction.[/quote]Isn't an issue here that the opioid component is not adsorbed reliably SC even though the alpha 2 is.

We often give xylazine SC for semi-feral/charity cats as its easier to grab the scruff and inject and its cheap as chips and it works well as a premed.

RE: Premeds

Bob Russell — Fri, 06 Oct 2017 09:56:22 GMT

We routinely premed s/c. They still get dozy!

A past nurse took some pleasure in telling me I was doing it all wrong so I left the BSAVA formulary open on the page (+ post it note) where it says these drugs can be given s/c.

I found the methadone doses recommended led to profound sedation. Perhaps time to revisit the drug with lower doses.

RE: Premeds

Neil Wheadon — Fri, 06 Oct 2017 09:43:08 GMT

[quote user="David Mills"]I encountered a practice recently giving premeds sc. Is this commonplace? [/quote]

The vast majority of places give I/M, one nurse uses the neck in a cat and likes it a lot

Personally I like to try the S/C route as I just don't like injecting animals I/M due to restraint issues and it must hurt more (am I being reasonable here?) I don't find it makes a lot of difference aside needing to wait a little longer before induction.

Neil

RE: Premeds

Martin Atkinson — Fri, 06 Oct 2017 08:54:31 GMT

We routinely use butorphanol + medetomidine for pre med for minor surgery but substitute the but. for buprenorphine where the process is likely to be more painful/prolonged. We do find bup. gives a more stable anaesthetic so belatedly starting to use more especially as it is available much more cheaply now. We would rarely find the need for extra opioids except for orthopaedics or where I know I've been a bit of a clumsy surgeon i.e. missed the linea alba in a bitch spay and then an NSAID mostly seems effective.

I have never found that either butorphanol or buprenorphine reduce the efficacy of pure opioids, then we would only rarely use morphine and hardly ever methadone. Ketamine is also a good analgesic but it is difficult to tell if the patient's happy recovery is because of this or it is just stoned!

RE: Premeds

Rob Loxley — Fri, 06 Oct 2017 08:40:10 GMT

[quote user="Christina Smith"]I am under pressure to change my premed away from torbutrol. Apparently it gives no pain relief advantage[/quote]

Certainly find the analgesia with bup/methadone to be superior; I mainly use butorphanol in combination for sedation only.

I tend to use methadone at 0.2-0.3 mg/kg in dogs (way below datasheet dose of 0.5-1 mg/kg); buprenorphine at 20 mcg/kg in cats and dogs

RE: Premeds

Catherine Jeanes — Fri, 06 Oct 2017 01:37:10 GMT

[quote user="David Mills"]

[quote user="Patrick Taylor"]

We got taught butorphanol antagonises other mu opiods like morphine/methadone. So in a way, it restricts the future short term (till the butorphanol wears off) analgesia you could give since it cuts out your options. I witnessed a HBC dog that was tachypnic due to opioid overdose that responded immediately with butorphanol. (Cheaper option for naloxone?)

[/quote]

It's incorrect. Butorphanol acts on kappa receptors so has no effect on mu agonists.

Butorphanol is a terrible analgesic. Medetomidine is fabulous.

We've had this discussion at work recently. Butorphanol by itself is inadequate as an analgesic in premeds.

What dose of methadone are you using in dogs and cats?

Personally I like an acp/meth/dom premeds. Lovely ga, minimal propofol and gas.

I encountered a practice recently giving premeds sc. Is this commonplace?

[/quote]

Butorphanol is an agonist at kappa receptors and an antagonist at mu receptors. Any pure mu opioid given after butorphanol would not be as efficacious until the butorphanol wore off. Butorphanol is a not a good analgesic and I only use it for sedation procedures.

In regards to the OP’s post, what doses of opioids are you giving? I almost never go over 0.2mg/kg methadone, and find this sufficient for routine surgery like you mentioned above, despite the data sheet doses being much higher. I usually use an ACP/methadone premed, or ACP/buprenorphine for very minor procedures, with local if possible. I have seen cats showing the dysphoric, hypersalivating signs you describe from 0.3mg/kg methadone, the signs you describe could be down to excessive opioid doses.

RE: Premeds

David Mills — Fri, 06 Oct 2017 01:04:10 GMT

[quote user="Patrick Taylor"]

[/quote]

It's incorrect. Butorphanol acts on kappa receptors so has no effect on mu agonists.

Butorphanol is a terrible analgesic. Medetomidine is fabulous.

We've had this discussion at work recently. Butorphanol by itself is inadequate as an analgesic in premeds.

What dose of methadone are you using in dogs and cats?

Personally I like an acp/meth/dom premeds. Lovely ga, minimal propofol and gas.

I encountered a practice recently giving premeds sc. Is this commonplace?

RE: Premeds

pjtaylor91 — Fri, 06 Oct 2017 00:09:34 GMT

RE: Premeds

Evelyn Barbour-Hill — Thu, 05 Oct 2017 22:48:39 GMT

Not an anaesthesiology () expert but:

[quote user="Christina Smith"] I am under pressure to change my premed away from torbutrol. Apparently it gives no pain relief advantage.[/quote]

No, but I'm not using it for pain relief. I'm using it at a premed dose to obtain smooth induction with a small dose of propofol. I use methadone or morphine at analgesic doses for opiate analgesia.

That's my attitude. Quite prepared to be told I'm silly.

RE: Premeds

Gillian Mostyn — Thu, 05 Oct 2017 22:39:58 GMT

ACP/methadone. Very happy with it, and much better analgesia than I used to see with butorphanol or buprenorphine.