Pyrantal pamoate has been used effectively against tapeworms for a long
time at double the normal dosing strength but this has been an off-
label usage. Recently, the FDA approved this dosage as effective for
the control of tapeworms. So now there are two FDA approved dewormers
available for use in horses- praziquantel and pyrantel pamoate at
double the standard dosage. Personally, I have used both in my
IR/Cushings boys with no problems. The praziquantel MAY be a problem so
as there is an effective, FDA approved, safe alternative that would
seem to be the prudent alternative to use in an animal when you aren't
sure if they will react.

Lavinia, George and Nappi