The “horse paste” is but one formulation of the ivermectin medication available from veterinary medicine supply houses.
Another brand name is “Ivomec” a solution that is normally for injection purposes, manufactured by Merial Saude Animal, Ltc, in Brazil, available online. 1.0% w/v sterile solution of ivermectin, Volume dosage is 1.5-2.0 ml for adult human.
Available online, but you may have to hunt for it.
The injection product is not as bioavailable when used orally, in any mammal. Injection dose orally is Wrong by up to 30%
Use oral paste product, with no other active ingredients other than 1.87% ivermectin.
Dose for most mammals (not cats, I believe) accurate on the weight marks