Ivermectin Pour on Dosage (Math Question)

[CharlieBaby]

Ahhh, the math! I realize dosing has been discussed in other threads, but I'm wondering if someone would be willing to explain the math behind pour-on Ivermectin dosing. It's bugging me that I can't figure out the link.

Ivermectin dose (A): The correct dosage of topical Ivermectin for chickens is .045 mL/lb (sources: here, here, and here). Chickens need .045 mL of active ingredient Ivermectin per pound of body weight.

Pour-on formula (B): I purchased Durvet Ivermectin Pour-On, which has 5 mg of Ivermectin per mL of solution. In other words, this particular form contains Ivermectin at a strength of 5 mg/mL, with the rest of the formulation being inactive ingredients.

Math trouble: This is where I'm getting stuck. I'm not sure how to reach the desired dose of .045 mL/lb using the pour on. The units are obviously different (mL/lb vs. mg/ML).

How does she do it? I see that Casportpony recommends .09 mL/lb of pour on Ivermectin, which equals .45 mL for a 5 pound hen (source: here). I assume this means that by applying .45 mL of Durvet Ivermectin Pour-On on my 5 pound hen, I'll be reaching the recommended dose of .045 mL active ingredient Ivermectin per pound of body weight...

Can someone explain how they converted the general recommended topical ivermectin dose (A) to the correct pour-on formula dose (B) -- how did you get from A to B?

 

[Wyorp Rock]

I think you may be overcomplicating things.

https://www.backyardchickens.com/ar...w-to-know-which-one-youre-dealing-with.73607/

Pour On has 5mg Ivermectin/ml, dosing is 1mg/kg
1 ÷ 2.2 x 1÷ 5= 0.09ml per pound of weight.


1% Injectable has 10mg Ivermectin/ml, dosing is 1mg/kg
1 ÷ 2.2 x 1 ÷ 10= 0.045ml per pound of weight.

The dose is not drops. Birds should be weighed or at least have their weights guessed and the proper amount should be given. I have bolded the amount I use.

There are two types, one is injectable, the other is a pour on. The doses are different.

The max dose for 1% Ivermectin is 1 mg/kg which is 0.045 ml per pound. This can be given orally, by injection, or topically.
A five pound hen would get 0.23 ml.

The minimum effective dose for 1% Ivermectin is 0.2 mg/kg which is 0.009 ml per pound. This can be given orally, by injection, or topically.
A five pound hen would get 0.045 ml

The max dose for Pour On Ivermectin is 1 mg/kg which is 0.09 ml per pound. This is given topically only.​

A five pound hen would get 0.45 ml.

The minimum effective dose for Pour On Ivermectin is 0.5 mg/kg, which is 0.045 ml per pound. This is given topically only.
A five pound hen would get 0.23 ml

DO NOT USE this on your dogs unless you are working with a vet!​

 

[Cowboy23]

So given all this math talk, I just purchased the pour-on Ivermectin. Do I put that mixture straight into an eye dropper and apply 5 drops to the back of the neck on my 5lb chicken?

 

[Debbie292d]

So given all this math talk, I just purchased the pour-on Ivermectin. Do I put that mixture straight into an eye dropper and apply 5 drops to the back of the neck on my 5lb chicken?

I'm not sure where you came up with 5 drops for a 5lb chicken from the info provided above, but that is what I do. 1 drop for the smaller silkies, 2 for the hens, 3 for the roosters, so yeah, 4 or 5 for a larger chicken sounds about right. This has to be repeated a week to 10 days later. We do NOT give any extra (for good measure) as they can be OD'd on this.

In all total, we've treated ours 5 times (10 treatments) for SLM. It works.

 

[casportpony]

So given all this math talk, I just purchased the pour-on Ivermectin. Do I put that mixture straight into an eye dropper and apply 5 drops to the back of the neck on my 5lb chicken?

The math for a five-pound chicken using the pour-on is:
5 ÷ 2.2 x 1 ÷ 50 = 0.45 ml

I'm not sure where you came up with 5 drops for a 5lb chicken from the info provided above, but that is what I do. 1 drop for the smaller silkies, 2 for the hens, 3 for the roosters, so yeah, 4 or 5 for a larger chicken sounds about right. This has to be repeated a week to 10 days later. We do NOT give any extra (for good measure) as they can be OD'd on this.

In all total, we've treated ours 5 times (10 treatments) for SLM. It works.

I think if you did the math, you would see that you are under-dosing them.

 

[Debbie292d]

The math for a five-pound chicken using the pour-on is:
5 ÷ 2.2 x 1 ÷ 50 = 0.45 ml


I think if you did the math, you would see that you are under-dosing them.

Perhaps, but I was for sure not wanting to overdose them because we have to turn around and give them that in 7-10 days again. I'm too scared to give them too much, and what we've been doing for nearly a decade works. It's a bi-annual ritual around here with these silkies!

 

[casportpony]

Perhaps, but I was for sure not wanting to overdose them because we have to turn around and give them that in 7-10 days again. I'm too scared to give them too much, and what we've been doing for nearly a decade works. It's a bi-annual ritual around here with these silkies!

I'm glad it works for you, but keep in mind that underdosing is one reason medications lose their efficacy.

And full disclosure, dosing by "drops" or "pea-sized blobs" are two of my pet peeves.

 

[Debbie292d]

I'm glad it works for you, but keep in mind that underdosing is one reason medications lose their efficacy.

And full disclosure, dosing by "drops" or "pea-sized blobs" are two of my pet peeves.

It worries me because they've got some in their system by the time we're doing the second dose, and nowhere does it say to go less on the second dose.

We do the same dose both times, but now it's piggybacking onto the previous one. This is only for SLM, not for deworming, although maybe it does that too if they had any.

At least this is only an every-other-year thing.