Re: Pergolide versus Pergolide Mesylate Dosing #pergolidestrength

Kathy Brinkerhoff

Hi All,

I posted this email from Boehringer Ingelheim to Dr. Kellon a couple of weeks ago.   Lj  started this discussion a couple of months ago because when he read his prescription label from Pet Health Pharmacy it stated that the capsules in the bottle contained 4 mg of pergolide mesylate and he wanted to know why it stated 4 mg since Jesse needed 3 mg of pergolide daily.  I followed up because I needed to transition my horse from 3 mg of Prascend to 3 mg of compounded pergolide.  I called BI and was told by a vet tech that 1 mg of prascend is equal to 1 mg of pergolide mesylate which based on the email below was incorrect information.  Other members posted Prascend inserts  from the UK and France that stated that 1 mg of Prascend is formulated from 1.3 mg of pergolide mesylate.  So why the difference in the US insert information for a product that is supposed to be the same "world wide" ??   I posted the question on CIR0615 because this was very confusing to me and Dr. Kellon contacted BI posted her email response from BI.   In the email response Dr. Weaver states the "language is different from US to UK"  ??? What does that mean?  Simply put worldwide 1 mg of Prascend is "metabolized" from 1.3 mg of pergolide mesylate.  So if my horse is on 3 mg of Prascend and I switch to a compounding pharmacy and I want the dosage the same I need 3.9 mg/4mg of pergolide mesylate to fulfill my prescription request of 3 mg of pergolide.  One needs to know how your compounding pharmacy is formulating/metabolizing the prescription your vet sends to them.  

This is my understanding of the Prascend vs Pergolide Mesylate dosing discussion.


Dr. Kellon's Post (CIR 0615)

This is the reply from BI:

Thank you for contacting Boehringer Ingelheim Veterinary Technical Services. You raised a very good question that, frankly, took a few days to circulate and find the answer.


The brief answer is, Prascend is the same worldwide. So, as you identified, the language is different from US & UK. No matter US or UK, there is 1.3 mg of pergolide mesylate (the salt) and once metabolized, 1 mg of pergolide.


So, to answer your question below, 1 tablet contains 1 mg of actual pergolide (1.3 mg of pergolide mesylate).


Let us know if you have further questions.


Best regards,


Kerby Weaver, DVM

Technical Service Veterinarian

A Boehringer Ingelheim Vetmedica Inc.


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