Wednesday, March 11, 2009

More thoughts on pergolide

After an earlier post about the stability of compounded pergolide, a few other points we thought worth mentioning came to mind:
One is that there is no "standard" dose as there is for most other meds. In other words, there is nothing that says every horse should receive X mg/100 lbs body weight. It varies from horse to horse. If your starting dose doesn't seem effective, your vet may want to recheck ACTH levels and adjust as needed. We've had to adjust 2 or 3 times on some horses to get it right, waiting at least a month or more between the time we change dose and the next test. Pergolide is not one of those things that works overnight.

Second, be sure you know what concentration your pharmacy sells. We've had some pergolide that was 1mg/ml, meaning the horse gets 1 ml of liquid to get 1mg of the drug. We've also had some that was 0.25mg/ml (4 ml liquid = 1mg of drug) and now use 0.20mg/ml (5 ml of liquid = 1 mg of drug.) One advantage to the more dilute form is a lesser difference in dose if you don't measure to the exact hair.

Finally, *when* you test ACTH levels has an effect on results. ACTH naturally increases as winter approaches and is lower in summer, so season will affect your test results.. Some people compensate by giving a different dose of pergolide in the winter than in the summer. We haven't done that, but it is something to be aware of.

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