Discussion on Dexamethasone and hives
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| Author |
Message |
   
kristen harding New Member Username: 6harding
Post Number: 2 Registered: 4-2008
| | Posted on Wednesday, Apr 30, 2008 - 5:00 pm: |   |
Hi. This is the second year in a row that we've been dealing with seasonal hives. Last year we did allergy testing, tried taking all foods away and slowly introducing them back, covered him in fly sheets, moved to a new barn, etc....all to no avail. The only thing that worked was dex. Then he cleared up about 6 weeks to 2 months later. Now, we're at it again. My vet doesn't want to try the pred. and hydroxine route because he is a show horse and we can't use the hydroxine and he thinks the pred. would wear off too quickly. So, how much is too much and how long is too long on the dex? I've read the articles and still don't know the answers. Thanks, Kristen |
   
Robert N. Oglesby DVM Moderator Username: dro
Post Number: 20571 Registered: 1-1997
| | Posted on Thursday, May 1, 2008 - 7:26 am: |   |
Hello Kristen, There are no clear cut answers to the questions of how much dexamethasone or how often is too much in the horse. In general the dexamethasone is not toxic itself though with long term use the horse needs to be monitored for Cushings disease. The most serious concern is its effects on the adrenal glands with long term use, adrenal suppression, and then discontinuation. However there are no studies that clearly indicate how sensitive the horses adrenal glands are to long time use and only one case summary published on iatrogenic Addisons that I have ever been a able to find. That horse was on frequent anabolic steroid administration for several years. For more on these conditions see Treatments and Medications for Horses » Anti-inflammatories (NSAID's, Steroids, Arthritis Rx) » Steroids, Overview of Antiinflammatory Use. There are also many individual factors that will figure into this calculation of what is too much: the type (salt) of dexamethasone used, the dosage, the frequency, and the route of administration. Two studies suggest that .05 mg/kg of a dex solution given IV will allow the adrenal gland to recover in 4 days but repeated administration is not studied. One should note these doses are much smaller than those used for very long times in serious autoimmune diseases of horses. DrO |
   
kristen harding New Member Username: 6harding
Post Number: 5 Registered: 4-2008
| | Posted on Thursday, May 1, 2008 - 10:42 am: |   |
Thanks for your response. So am I to understand that there have NOT been reported cases of horses on dex. for 4, 6 or even 8 weeks that have had significant problems? We are trying to get as many days in between doses and the lowest dose possible that will work for our hives problem. Thanks again, Kristen |
   
Robert N. Oglesby DVM Moderator Username: dro
Post Number: 20581 Registered: 1-1997
| | Posted on Thursday, May 1, 2008 - 7:26 pm: |   |
None that I am aware of and I have looked. DrO |
   
Susanne Ryder Member Username: sryder11
Post Number: 35 Registered: 6-2003
| | Posted on Sunday, May 4, 2008 - 10:42 am: |   |
Kristen my horse was on Dex for almost 3 months between Aug and Oct last year for severe hives - you can read about it in my previous thread Hives and Dex Dosage. Even after that the hives kept recurring. The vet eventually gave him one shot of Vetalog and the hives were gone for good, at least for last season. I was nervous about giving him this but it seemed considerably more effective than all that Dex and in your case it would be out of your horse's system in two weeks or so. Maybe talk about this with your vet if the hives persist. |