[JBandRio]

I didn't really want to drag the other recent threads back up for this, so I'm starting a new one.

One thing we had talked about in the last one was why the desert regions were in the 10% or less range of tapeworm infestation. I thought it had to do with the humidity, but it doesn't.

Tapeworms are transferred around by the mites that eat the eggs. The mites live in the topsoil, but in desert, there is no "topsoil", it's sand. So, mites can't live there. Obviously there are parts of populated desert areas that have developed topsoil, allowing the mites to live there.

But the biggest thing I wanted to find out, hopefully from Madick or Ryle or anyone else who can find out, is this:

The only study on the efficacy of praziquantel I can find uses a 9% paste at 1mg/kg BW.
http://www.sciencedirect.com/science...ae81a8e495ac4e

(that same study is listed in different publications)

But, Zimecterin Gold is only a 7.75% paste at 1mg/kg, and Equimax is a 14.03% paste at 1.5mg/kg.

WHY is ZG dosed at a rate lower than what studies showed to be pretty darn effective?

Is the 1.5x dose in the Equimax going to lead to resistance? Or is that making darn sure it doesn't lead to resistance any time soon?

[Chester]

I just bought a box/bottle of Imax gold yesterday.

The does rate on it is 1.5mg kg for praziquantel.

[JBandRio]

I had to look up Imax Gold - never heard of it! It seems to be the Australian version of Equimax here, with the same dosing rate as Equimax.

[Ryle]

There have been other studies done and even at 1mg/kg efficacy of praziquantel against equine tapeworms is 99.7% so even the lower dose in Zimectrin Gold is very effective. However, the 1.5mg/kg dose has been shown to be 100% effective which means that it should help prevent parasite resistance when given at an appropriate dose because if you kill 100% of the worms there is nothing left to develop or pass on resistance.

[JBandRio]

Ok Ryle, help me with the math here

If the study was done on 9% prazi, at a dose of 1mg/kg, that is more than the 7.5% prazi at a dose of 1mg/kg that is in the Zimecterin Gold.

Are you saying there are studies that show that the 7.5% concentration at 1mg/kg is 99.7% effective?

[Madick]

The lower concentration of praziquantel makes it kill off only adult tapeworms, the higher dose takes care of all the stages inside the horse.

I don't know why you'd want the lower dose, it sounds totally wrong in my ears. Here in Sweden we first got Equimax, and the other brands were quick to make their ivermectin and moxidectin combined with praziquantel (called the brand name + Comp) but the lower dosage.

I heard just today one of my clients who had been prescribed with one of the "comps" instead of Equimax as I had told them, because their vet had said they were the same... scary.

[JBandRio]

That really just goes to show you how uneducated many vets are about "commercial" products

[Ryle]

Originally Posted by JBandRio

Ok Ryle, help me with the math here

If the study was done on 9% prazi, at a dose of 1mg/kg, that is more than the 7.5% prazi at a dose of 1mg/kg that is in the Zimecterin Gold.

Are you saying there are studies that show that the 7.5% concentration at 1mg/kg is 99.7% effective?

You can ignore the 9% and the 7.5%--these just describe the concentration of the drug in a solution. It was still dosed at 1mg of praziquantel per kg of body weight. It's just that it takes more volume of solution to provide that 1mg/kg if the solution is 7.5% than if it's 9%

[Dawn]

If you look at Zimectrin Gold it also has a lower ivermectin doseage as well. I've never understood it. Don't use it, don't recommend it to people either.

If you're going to pay that much money for a product, you might as well get a 'full' doseage.

[JBandRio]

Ok Ryle, thanks, that's the part I was missing.

Dawn, yes, I don't understand that either. A standard ivermectin-only paste is 1.87% ivermectin, which is what the Equimax is as well.

I have even more reason now to not use ZG. I know you are aware of the issues with the mouth ulcers. Did you know that Merial themselves have made this "public" since 2004??? But every single person I have talked to who contacted Merial were told there was no such issue, that they had never heard of the issue. Yet here is it, from 2004
http://www.fda.gov/cvm/FOI/141-214s071304.pdf