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  Discussion on Isoxsuprine?
Author Message
Member:
Aannk

Posted on Friday, Mar 7, 2003 - 9:44 am:

Dr. O.,
Your article says
"AHSA: forbidden under NFS and TS rules." What are NFS and TS rules? Does this mean it is forbidden at all AHSA shows? Just curious.
Alicia
Member:
Buddil

Posted on Friday, Mar 7, 2003 - 10:01 am:

Hi, my horse is on Isoxuprene for "navicular synDrOme" and before I put him on this medication I did call AHSA to verify that it is a legal drug, due to hearing both it was and wasn't from fellow horsepeople. It is, indeed, a legal drug now due to so many horses with "navicular synDrOme". I show in dressage. If you would like to inquire, you can send an email to them or call them, I believe their number is on the web site under USA Equestrian or AHSA will bring you to the link. Hope this will help you!
Cathy
Member:
Aannk

Posted on Friday, Mar 7, 2003 - 10:29 am:

Thanks, Cathy. Is there a link to the drug rules on the USAEq site? I haven't been able to find it. I remember hearing Lavender is forbidden, and I got a free bottle of a really nice smelling shampoo at an A show, which had, guess what, Lavender in it!!
Thanks,
Alicia
Member:
Buddil

Posted on Friday, Mar 7, 2003 - 8:17 pm:

Hi Alicia, I don't think there is a link, as I recall I phoned them and had a representative answer my question. They were very polite and helpful. I think they have an area on the website for emails and they can help you there, too. I once had a question regarding a bits legality and used their email for that and they answered it right away, very helpful! It is amazing what you would think is legal and the things that are not! I also needed to know if bute was legal and they gave me a recommended doseage that would be legal, 5 days low dose, then 2 days off and it would not build up to test at too high of a level. I always thought bute was forbidden, but not at the USDF lower levels, but it is FEI forbidden. Best of luck! Cathy
Moderator:
DrO

Posted on Saturday, Mar 8, 2003 - 4:26 pm:

Isoxsuprine use to be considered a masking drug and was on both the No Foreign Substance Rule and Therapeutic Substance Rule. I went to the AHSA site to verify Alicia's comments and they are down with maintenance, so I will check again next week.
DrO
Moderator:
DrO

Posted on Tuesday, Mar 11, 2003 - 10:56 am:

I can find no specific mention of isoxsuprine on either the USA Equestrian or the FEI site in there drug rules. So I called the USA Equestrian folks also and here is what I was told:
1) Permitted under the Therapeutic Substances rules for all disciplines.
2) Permitted under the Forbidden Substances rules for all disciplines with the exception of FEI and Endurance. For more and recommended withdrawl times, see » Equine Medications and Nutriceuticals » Miscellaneous Drugs » Isoxsuprine.

If you assume this is a effective medication it is difficult to see how this medication could possibly comply with the spirit of the No Therapeutic Substance rules (Article 409). I wonder if it is possible that it might slip by because there is either no measuarble physical effect after oral administartion or because almost no isoxsuprine (less than 3%) is absorbed from the digestive tract so there is little to measure in the blood? I leave you with this latest review of isoxsuprene use in the horse:

J Vet Pharmacol Ther 2002 Apr;25(2):81-7
Isoxsuprine hyDrOchloride in the horse: a review.
Erkert RS, Macallister CG.

Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Oklahoma State University, Stillwater, OK 74078, USA.

Isoxsuprine hyDrOchloride has been suggested for use in horses for treatment of navicular synDrOme and laminitis. The drug has been shown to be a beta-adrenoreceptor antagonist with beta-adrenoreceptor agonistic properties, with both characteristics contributing to vasodilation and uterine relaxation. In addition, the drug is capable of decreasing blood viscosity and platelet aggregation. Studies have shown i.v. isoxsuprine to have a plasma half-life of <3 h with a large apparent volume of distribution. Cardiovascular effects resolve rapidly following i.v. administration, but are absent with oral dosing. Oral bioavailability is 2.2% with a high first pass effect. Isoxsuprine has an apparent affinity for melanin that may contribute to extended renal excretion. Clinical trials appear to support the use of isoxsuprine for treatment of navicular disease. However, poor bioavailability, lack of cardiovascular effects following oral administration, superficial support in clinical trials, and new evidence regarding the pathogenesis of navicular synDrOme indicate that the use of isoxsuprine for treatment of navicular synDrOme or laminitis is questionable at best.
DrO
Moderator:
DrO

Posted on Tuesday, Mar 11, 2003 - 11:27 am:

Cathy I almost forgot, corrections to The Advisors factual data always brings a reward. Thank you for helping correct the information on isoxsuprine rule changes. 3 months will be added to your membership free.
DrO
Member:
Aannk

Posted on Wednesday, Mar 12, 2003 - 12:52 pm:

Dr O.,
I agree with your assessment of the Article 409, which is why I thought it must be prohibited. Thanks for clearing it up.
Alicia
Member:
Buddil

Posted on Thursday, Mar 13, 2003 - 5:19 pm:

Thanks Dr. O., 3 months is great!

Cathy
Member:
estrella

Posted on Friday, Sep 25, 2009 - 5:21 pm:

Hello! So my little mare foundered, maybe sorta. She doesn't react to the hoof testers, no heat, no pulse. Well she does have a pulse but not the founder pulse. Not in any type of distress..just started sore on one foot, then both..and seemed unhappy, stiff. so vet treated for founder. Banamine (sp?), I use it enough so I should know..and..drum roll...Isoxuprine! 12 tabs 2x's a day..(under vet's direction). Then stop the banamine..just isoxuprine..with the recommended treatment..she didn't drink alot, wasn't eating well...looked terrible, you know "green". So stopped the Isoxuprine..changed to 1 gram of bute..she started feeling better...had a vet check..one foot still pretty sore..recommended restart Isoxuprine 2 days then off bute or banamine..she again didn't drink and looked like she felt horrible. So acting as a freelance vet..took her back off the Isoxuprine, back on 1 gram of bute 1x a day..she's happy not 100% sound..but at least looking like we are moving in the right direction. I throw in Ulcerguard. So question...can Isoxuprine make them queezy? Should have checked here first before I ever gave it...oh yea, 2 weeks into the soreness..Shoe boil! Ran 102.2 (on 1 gram bute). Vet back out and then Uniprim plus all of the other stuff. We are complete on the antibiotic treatment.
Moderator:
DrO

Posted on Saturday, Sep 26, 2009 - 11:37 am:

Hello estrella,
We cover your question and more in the article on this subject. To get to it quickly go to the top of the page and click on » Isoxsuprine ».
DrO
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