Drugs

US Equestrian has a fairly comprehensive guide that outlines which drugs are permitted and which drugs are not. Even so, some questions don't have a definitive, ready-to-go answer. Case in point, prednisolone.

Izzy was recently prescribed prednisolone for his Seasonal Recurrent Dermatitis (SSRD) which is being caused by midges. My vet reminded me to check out the withdrawal time with my dressage governing body, US Equestrian. While I was in his office, we quickly found the 2020 USEF Guidelines for Drugs and Medications. We located the Common Prohibited Substances page and quickly scrolled through the list. Prednisolone was not on either list (permitted with MRF and no MRF accepted). I assured him that I would dig more deeply.

Knowing that a steroid had to be on some list somewhere, I later started flipping through the pages, reading a bit more closely. On page 8 of the 2020 guide, page 12 of the 2019 guide, there is a list that details how long drugs remain detectable. Prednisolone is not on the list, but methylprednisolone is, and it's detectable for 14 days. That got me worried.

I spent a fair amount of time asking Google to describe the differences between methylprednisolone and prednisolone. The only results I got were for methylprednisolone and prednisone. I called my vet back. He assured me that methylprednisolone and prednisolone are indeed two different medications. Methylprednisolone is much more powerful and acts more quickly. Prednisolone falls under the category of "corticosteroids other than methylprednisolone and isoflupredone, e.g. triamcinolone and betamethasone."

NOT methylprednisolone.

The issue for Izzy is how long the drug is detectable. We have a show in less than two weeks. We have another show two weeks after that. Since the detectable time for methylprednisolone is two weeks, he wouldn't have been able to have a dose for a full month. That would not have been good.

Fortunately, the detectable time for other corticosteroids like prednisolone is seven days. This means we can't follow my vet's initial treatment plan of two weeks of 20 tablets a day followed by two weeks of 18 tablets a day followed by ... you get the idea. Instead, he'll get his last dose on Friday. He'll be off the medication for a week for a two-day show October 24th and 25th. He'll then get another week of the prednisolone, and then he'll go off it for another week so that we can go to another two-day show November 7th and 8th. He'll then go back on the prednisolone until November 30th.

His skin is finally not itchy , and it's nearly healed over.

Fortunately, Izzy has had enough medication - IV, oral, and topical, that his skin has finally healed over, and he is no longer itchy. Of course our cool evenings have probably helped nearly as much as the drugs. Our lows have been in the 50s which has no doubt annoyed the midges. I just hope that being off the prednisolone for a week won't allow the little boogers to gain a new foothold.

Fingers crossed!