Muscle relaxants in urethral obstruction

RE: Muscle relaxants in urethral obstruction

Martin Atkinson — Mon, 17 Apr 2017 21:54:33 GMT

[quote user="ih220"]At BSAVA did they specifically mention oral diazepam[/quote]Diazepam was touted as a useful drug but to be used with caution because of the risk of neurological and hepatic problems so best avoided orally in the medium to long term so amitryptilline is better.

RE: Muscle relaxants in urethral obstruction

Anthony Dennison — Thu, 13 Apr 2017 16:22:34 GMT

Last couple of cats we've had in that were recurrent blockers (going home and not peeing, or not peeing between removing urinary catheter and discharge), have gone home with a low dose of diazepam and personally I've seen a positive response. I know numbers are low, perhaps it's relaxing the urethral sling muscles that might be taught due to pain?

RE: Muscle relaxants in urethral obstruction

Emily Rainbow — Wed, 12 Apr 2017 21:16:08 GMT

Didn't attend the FLUTD lecture but during the urinary text surgery lecture it was suggested that even though 2/3rd of the feline male urethra is skeletal muscle rather than smooth muscle that the lecturer didn't think Diazepam did anything useful. They suggested either Prazozin or Phenoxybenzamine (lecturer liked one, person running the stream liked the other).

so i guess there's no real evidence either way? I admit I do tend to use Prazozin and Diazepam, maybe the anxiolytic effects help more?

RE: Muscle relaxants in urethral obstruction

ih220 — Wed, 12 Apr 2017 19:01:38 GMT

I'm pretty sure I did these two conscious. It is perhaps relevant to the fact that I sent these home that both these owners were conscientious and very willing to monitor closely/provide TLC/bring back asap if recurring.

I think giving injectable sedation of some sort and into a quiet kennel is maybe a better compromise to avoid the risks of oral diazepam.

At BSAVA did they specifically mention oral diazepam or were you referring more to the general option of conservative management without a catheter?

RE: Muscle relaxants in urethral obstruction

Thomas Johnson — Wed, 12 Apr 2017 18:01:06 GMT

[quote user="ih220"]

The two I saw only needed a one-off cystocentesis in the inital consult then sent home so def cheaper than hospitalisation etc.

[/quote]

If I see a blocked cat that's still quite well in itself I will often given them acepromazine and buprenorphine and put them in a quiet kennel with a litter tray for half an hour, I've had a few that have then urinated on their own; most don't, but it does avoid a few anaesthetics and catheterisations.

RE: Muscle relaxants in urethral obstruction

Martin Atkinson — Wed, 12 Apr 2017 17:54:04 GMT

[quote user="ih220"]

The two I saw only needed a one-off cystocentesis in the inital consult then sent home so def cheaper than hospitalisation etc.

[/quote]Do you do your cysto's under sedation? I've found several, which once they were sedated, relaxed enough for the obstruction to clear and pee themselves.

RE: Muscle relaxants in urethral obstruction

ih220 — Wed, 12 Apr 2017 17:45:42 GMT

The two I saw only needed a one-off cystocentesis in the inital consult then sent home so def cheaper than hospitalisation etc.

RE: Muscle relaxants in urethral obstruction

Martin Atkinson — Wed, 12 Apr 2017 17:24:13 GMT

[quote user="ih220"]I did have two separate acutely blocked cats with a history of previous blockage where owners declined any further GAs for unblocking (mixture of cost/welfare grounds) and requested euthanasia. In both cases I offered cystocentesis and oral diazepam as an alternative to euthanasia, with appropriate discussion of the probability of recurrence in future and the risks of diazepam (this was a while ago but liver damage was the main worry I think?), then sent them home for TLC with owners. Obviously with instructions to bring them back for euthanasia if the blockage recurred as the bladder filled up. In both cases the blockage resolved, presumably due to relaxation of a spasming urethra. [/quote]This approach was suggested in the talks on FUS/FLUTD/FIC at congress mainly as an alternative for clients who couldn't/wouldn't pay for repeated or indwelling catheterisation. I actually fail to see how repeated cystocentesis can be any cheaper but c'est la vie! Nonetheless, this approach does seem to work so is a valid way to treat them.

RE: Muscle relaxants in urethral obstruction

ih220 — Wed, 12 Apr 2017 17:11:00 GMT

Not a study but I did have two separate acutely blocked cats with a history of previous blockage where owners declined any further GAs for unblocking (mixture of cost/welfare grounds) and requested euthanasia. In both cases I offered cystocentesis and oral diazepam as an alternative to euthanasia, with appropriate discussion of the probability of recurrence in future and the risks of diazepam (this was a while ago but liver damage was the main worry I think?), then sent them home for TLC with owners. Obviously with instructions to bring them back for euthanasia if the blockage recurred as the bladder filled up. In both cases the blockage resolved, presumably due to relaxation of a spasming urethra. No doubt this couldn't be recommended as a first line approach but as a cheap and less invasive option where the alternative was euthanasia it worked in these two cases.

The report below is about an approach using cystocentesis and sedation which was successful in 11 of 15 cats where traditional management was declined. This sort of result suggests to me that the role of urethral spasm in feline blockages is really crucial so muscle relaxants would seem to make sense.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4511701/

I wonder whether the human experience reported of urethral as well as ureteral dilation could be due to the release of trapped urine from the kidney/ureter into the bladder and subsequent trigger of urination, rather than a direct effect on the urethral muscle?

RE: Muscle relaxants in urethral obstruction

Anthony Todd — Tue, 11 Apr 2017 20:11:42 GMT

[quote user="Thomas Johnson"]it has no effect on the urethra, so not much use in cats with urolithiasis.[/quote]

Well the consultant urologist just nodded when I made the observation but, to move on.

As nobody, when FUS was last discussed, ever mentioned drugs which dilated the urethra I threw it in the cauldron.

Now it seems that atracurium besylate [and there's even a paper] may be helpful.

J Small Anim Pract. 2012 Jul;53(7):411-5. doi: 10.1111/j.1748-5827.2012.01239.x.

Effect of intraurethral administration of atracurium besylate in male cats with urethral plugs.

Galluzzi F1, De Rensis F, Menozzi A, Spattini G.

Anything that helps avoid the complications of the common traumatic unblocking of a FUS cat is to be welcomed.

RE: Muscle relaxants in urethral obstruction

Thomas Johnson — Tue, 11 Apr 2017 18:43:41 GMT

[quote user="Anthony Todd"]

[quote user="Thomas Johnson"]but it doesn't look as though it has any direct effect on the urethra.[/quote]

I promise you it has and it is very impressive!!

It is the first line NHS treatment for ureteral stones, as opposed to mechanical removal, but also has an obvious effect of dilating the urethra and is used for that when the urethra is narrowed by prostate pathology.

[/quote]

The effect on the ureter isn't really relevant to this discussion as we're talking about urethral obstructions. And yes it dilates the urethra if it is being constricted by an enlarged prostate, but if the prostate is normal it has no effect on the urethra, so not much use in cats with urolithiasis.

RE: Muscle relaxants in urethral obstruction

Anthony Todd — Tue, 11 Apr 2017 18:22:40 GMT

[quote user="Thomas Johnson"]but it doesn't look as though it has any direct effect on the urethra.[/quote]

I promise you it has and it is very impressive!!

RE: Muscle relaxants in urethral obstruction

Thomas Johnson — Tue, 11 Apr 2017 17:50:45 GMT

[quote user="Anthony Todd"]

[quote user="Thomas Johnson"]My understanding was that in humans they were used for ureteric obstructions rather than urethral obstructions. The ureters have smooth muscle and the urethra has striated muscle.[/quote]

That may well be so but, only having had personal experience of another ureteral dilator, tamsulosin HCl, which may work in a different way.

I can assure you it works dramatically and spectacularly on both the ureter and urethra and is sold as "Maxiflo"....

[/quote]

Tamsulosin is an alpha1 adrenoceptor blocker that acts on smooth muscle at the neck of the bladder and in the prostate and is used to treat increased intra-urethral pressure due to benign prostatic hyperplasia, but it doesn't look as though it has any direct effect on the urethra.

RE: Muscle relaxants in urethral obstruction

Martin Atkinson — Tue, 11 Apr 2017 16:55:44 GMT

[quote user="robloxley"]

Interesting talk at BSAVA on blocked cats mentioned intra-urethral atracurium to unblock https://www.ncbi.nlm.nih.gov/pubmed/22747734
And prazosin potentially reducing re-blockage postop

[/quote]I was at a talk by Jodi Westropp on FUS/FLUTD/FIC and heard that there is no evidence that prazosin helps. Amitryptilline may be useful in the longer term if nothing else works but not to start as it may make it worse and diazepam as well but dodgy in cats. Seems we're not all singing from the same song sheet.

RE: Muscle relaxants in urethral obstruction

Anthony Todd — Tue, 11 Apr 2017 16:24:51 GMT

That may well be so but, only having had personal experience of another ureteral dilator, tamsulosin HCl, which may work in a different way.

I can assure you it works dramatically and spectacularly on both the ureter and urethra and is sold as "Maxiflo"....

RE: Muscle relaxants in urethral obstruction

Thomas Johnson — Tue, 11 Apr 2017 15:57:26 GMT

[quote user="Anthony Todd"]

[quote user="mariette asselbergs"]Urethral musculature is striated muscle.[/quote]

Is urethral muscle different in humans??

[/quote]

My understanding was that in humans they were used for ureteric obstructions rather than urethral obstructions. The ureters have smooth muscle and the urethra has striated muscle.

RE: Muscle relaxants in urethral obstruction

Anthony Todd — Tue, 11 Apr 2017 14:47:57 GMT

[quote user="robloxley"]

Interesting talk at BSAVA on blocked cats mentioned intra-urethral atracurium to unblock https://www.ncbi.nlm.nih.gov/pubmed/22747734
And prazosin potentially reducing re-blockage postop

[/quote]

CLINICAL SIGNIFICANCE:

The results of this study indicate that in adult male cats with urethral plugs, urethral administration of atracurium besylate increases the proportion of animals in which the obstruction is removed at the first attempt and reduces the time required to remove the urethral plugs.

Yipee!!

RE: Muscle relaxants in urethral obstruction

Anthony Todd — Tue, 11 Apr 2017 14:43:39 GMT

[quote user="mariette asselbergs"]Urethral musculature is striated muscle.[/quote]

Is urethral muscle different in humans??

RE: Muscle relaxants in urethral obstruction

Rob Loxley — Tue, 11 Apr 2017 13:49:54 GMT

Interesting talk at BSAVA on blocked cats mentioned intra-urethral atracurium to unblock https://www.ncbi.nlm.nih.gov/pubmed/22747734
And prazosin potentially reducing re-blockage postop

RE: Muscle relaxants in urethral obstruction

mariette asselbergs — Tue, 11 Apr 2017 13:22:13 GMT

References:

Cooper Edward S . Controversies in the management of feline urethral obstruction. Journal of Veterinary Emergency and Critical care 25 (1) 2015 pp 130-137

Jodi Westropp (2017) Feline interstitial/idiopathic cystitis, BSAVA Congress 9^th April.

Mariette

RE: Muscle relaxants in urethral obstruction

mariette asselbergs — Tue, 11 Apr 2017 13:06:40 GMT

Urethral musculature is striated muscle. None of the relaxants have been shown to work. What does work is giving an epidural (between sacrum and coccygeal 1, or between Cocc 1 and 2 like in sheep). Use 0.2 ml lidocaine plus 0.05 ml xylazene for long action ( 4-8 hrs). Instead of xylazene you can also use morphine or medetomidine but they work shorter.

Mariette

RE: Muscle relaxants in urethral obstruction

Anthony Todd — Tue, 11 Apr 2017 08:59:12 GMT

[quote user="Kathryn Burton"] They seem a good idea in theory but I don't know if there's any evidence to support that![/quote]

There are some that are amazingly effective in humans so it seems odd that none have been tried, or more, in cats particularly.

Can't be enough profit in it but you'd think someone like Dechra would give it a go.

All the basic stuff is done already and they and others have done it with all the really profitable ones, aided by the ridiculous industry serving VMD regulations.