Converting Ivermectin Dosages - Medication & Math Experts Needed

[ytr45]

This struck me as very strange when I first became aware of it. Most of the lyme doctors throughout the country are prescribing the human version of ivermectin for lyme related parasites. The human version is called Strombectol and -WHAT A SCAM!! It costs hundreds of dollars for a few pills. I think even with the insurance it was $280 for 20 pills.

I told my doctor that a tube of ivermectin paste for a 1200 lb horse is only $4. She said it was fine to take that instead of the pricey human version.

The strombectol is a 3 mg pill. My tube of ivermectin says Ivermectin paste 1.87%. The tube is 6.08 grams. How would I go about converting the paste to 3mg dosages?

Also, there are warnings on the tube that say “Not for use in humans” and other warnings. Kind of scares me. Is there anything else in the paste that could be harmful?

Thanks.

[JB]

Until you know the total amount of strombectol you should be ingesting you can’t begin to figure out how to calculate how much Ivermectin paste to take. It’s NOT as simple as figuring out how much of a tube works out to 3mg.

If your Dr said it’s ok to use that then your Dr should be telling you how much to take.

I have zero idea if that’s actually a good idea, just stating the above

[mswillie]

Ivermectin paste at 1.87% is the same as 18.7 mg/gram.

3 mg/18.7 mg /gram = 0.16 gram. So 0.16 grams of paste = 3 mg

The dosing chart is here: http://www.rxlist.com/stromectol-drug/indications-dosage.htm

If you decide to use it I would run your calculations by your doctor.

[deltawave]

Most of the lyme doctors throughout the country are prescribing the human version of ivermectin for lyme related parasites

You sure about that? It seems to me it’s more like an alternative/subculture thing in the jungle of Lyme disease diagnosis and treatment.

[Simkie]

You’ve really got to know how much ivermectin is in that 3 mg tablet of Stromectol before you can figure out how much of your horse’s ivermectin paste you can take.

Here’s the info from Merck: http://www.merck.com/product/usa/pi_circulars/s/stromectol/stromectol_pi.pdf

I wasn’t able to find the amount of ivermectin in that 3 mg tablet of Stromectol from that info, but I just skimmed, so perhaps more careful reading will give you the info you need.

ETA: Ah, actual dosage instructions for ivermectin for people based on disease: http://reference.medscape.com/drug/stromectol-ivermectin-342657

[JB]

[QUOTE=mswillie;7024283]
Ivermectin paste at 1.87% is the same as 18.7 mg/gram.

3 mg/18.7 mg /gram = 0.16 gram. So 0.16 grams of paste = 3 mg

The dosing chart is here: http://www.rxlist.com/stromectol-drug/indications-dosage.htm

If you decide to use it I would run your calculations by your doctor.[/QUOTE]

Apparently the dose of ivermectin is 200-mcg/kg for a person for this issue.

That is NOT the same thing as saying “3 mg/18.7 mg /gram = 0.16 gram. So 0.16 grams of paste = 3 mg” That only tells you how

A 55kg (121lb) person would then require 11,000mcg which is 11gm of ivermectin, which is more weight than a full tube of Ivermectin paste. If I did my math right. But regardless, the stromectol pill is a 3mg pill. That does not mean you take a 1.87% paste and extrapolate it down to a 3mg dose because your calculation doesn’t factor in the % ivermectin in that 3mg pill

[deltawave]

Pretty sure 11 grams of ivermectin is a really, really large dose not appropriate for humans. MCG = microgram. 1/1000th of a milligram.

A 200mcg/kg dose for a normal-sized (70kg) human would be 14 mg.

Generally if a pill says 3mg that means 3mg of the drug, not the mass of the actual pill on a scale. So the 3mg ivermectin pill contains 3mg of ivermectin, just like the 500mg penicillin pill contains 500mg of penicillin, and probably another several hundred milligrams of wax, fillers, coating, etc. That is not mentioned conventionally in talking about the sizes/strengths of medications. Just the active ingredient.

[Simkie]

[QUOTE=deltawave;7024358]
Generally if a pill says 3mg that means 3mg of the drug, not the mass of the actual pill on a scale. So the 3mg ivermectin pill contains 3mg of ivermectin, just like the 500mg penicillin pill contains 500mg of penicillin, and probably another several hundred milligrams of wax, fillers, coating, etc. That is not mentioned conventionally in talking about the sizes/strengths of medications. Just the active ingredient.[/QUOTE]

Oh, right–human medicine. Not like the “6.93 g” tube of Equioxx. I forget

[deltawave]

Liquid medications in general are complicated. Pastes probably fall into that category. Thank goodness I use virtually nothing that’s orally dosed in liquid form.

[mswillie]

[QUOTE=JB;7024338]
Apparently the dose of ivermectin is 200-mcg/kg for a person for this issue.

That is NOT the same thing as saying “3 mg/18.7 mg /gram = 0.16 gram. So 0.16 grams of paste = 3 mg” That only tells you how

A 55kg (121lb) person would then require 11,000mcg which is 11gm of ivermectin, which is more weight than a full tube of Ivermectin paste. If I did my math right. But regardless, the stromectol pill is a 3mg pill. That does not mean you take a 1.87% paste and extrapolate it down to a 3mg dose because your calculation doesn’t factor in the % ivermectin in that 3mg pill[/QUOTE]

You math is way off. 11,000 mcg is 11 mg.

And if a pill is a 3 mg gram pill that does indeed mean that there is 3 mg active pharmaceutical ingredient in the pill.

The question was “how do you convert the 1.87% paste into 3 mg doses”

0.16 gram (160 mg) of paste (provided it is homogenous) contains 3 mg of ivermectin.

[Ghazzu]

People who solicit drug dosages off the interwebz are fools, at best.
Do you really have that much faith in the math skills of strangers?

[deltawave]

I want to know how someone can possibly measure 0.16 mg of paste accurately! The dose for horses is the same as for humans–200mcg/kg. So a whole tube contains 113 mg. (200mcg/kg x 568 kg which is 1250 lb.) I don’t think the 0.16 mg number is therefore accurate. It would appear by my math (not my strong suit, however) that the dosage for a 100kg human would be the same dose as for a 100kg horse, so approximately 1/12th of the tube, much less for a smaller human. I still wouldn’t ingest a horse drug. I’d cough up for the human version–after asking my doctor for good evidence that ivermectin helps with Lyme disease and whether or not he/she had actual solid proof that I needed deworming! :eek:

People who solicit drug dosages off the interwebz are fools, at best.

True. The same might be suggested for practitioners prescribing dewormers for people with Lyme disease. :no:

[hosspuller]

OP … I am finishing up a regime of Doxycycline as a Lyme precaution after a tick bite & rash.

Since Ivermectin is only effective on invertebrates (insects), what is the purpose of taking the drug? Getting bit by a bug infects a person with bacteria not insects.

[deltawave]

Bacteria can be considered (somewhat incorrectly, I’ll admit) invertebrates, too, and so are snails and beetles. Ivermectin is for WORMS, primarily, and in some case lice and other creepy crawlies. And neither are ticks “insects”. And “getting bit by a bug” can infect a person with viruses, spirochetes, AND bacteria. But I digress . . .

There is a fringe (one of many-many-many) of people who believe that there is co-existing infection with worms that goes along with Lyme disease. Not supported by any medical literature whatsoever.

[JB]

Sorry, I really did mean mg and not gm - my paper here said mg, I typed gm

[CrowneDragon]

OP, my suggestion if you go the animal medication route is to get liquid ivermectin, which can be accurately dosed in a syringe. I did this with my dog yesterday and FWIW, the dose for dogs is tiny for heartworm prevention (maybe for Lyme its much bigger). He weighs 90 lbs and gets 0.05 cc (not 0.5) of the 1% solution. I measure it in a bitty syringe and the dose is about a drop.
Or do you like beef jerky? Maybe you can get Heargard soft chews

[JB]

This link says the Stromectol is “available in 3-mg tablets containing the following inactive ingredients: microcrystalline cellulose, pregelatinized starch, magnesium stearate, butylated hydroxyanisole, and citric acid powder (anhydrous).”- not that it contains 3mg of ivermectin.

[deltawave]

It is convention that in human medications, when a size or dosage is indicated, ONLY the active ingredient is being discussed. ALL pills have carriers, fillers, and inactive ingredients. These are NOT a part of the convention of sizing/dosing a pill. A 3mg pill contains 3mg of the active drug or pro-drug. Fillers, etc. are NOT considered in the sizing/dosing. That 3mg ivermectin pill might weigh 50mg or 500mg. but it contains 3mg of ivermectin. A pill that weighed 3mg in its entirety would be about the size of a sesame seed, probably.

[mswillie]

@deltawave;7024403

I want to know how someone can possibly measure 0.16 mg of paste accurately! The dose for horses is the same as for humans–200mcg/kg. So a tube contains 91 mcg. I don’t think the 0.16 mg number is therefore accurate. It would appear by my math (not my strong suit, however) that the dosage for a 100kg human would be the same dose as for a 100kg horse, so approximately 1/12th of the tube, much less for a smaller human. I still wouldn’t ingest a horse drug. I’d cough up for the human version–after asking my doctor for good evidence that ivermectin helps with Lyme disease and whether or not he/she had actual solid proof that I needed deworming! :eek:

The math isn’t that hard. 1.87% means that there is 1.87 mg of compound in 100 mg of paste. That converts to 18.7 mg of compound in 1000 mg (one gram) of paste. The tube contains 6.08 grams of paste, therefore one full tube contains 113.7 mg of ivermectin.

The concentration is a function of how much ivermectin is in a gram of paste. It is completely independent of the recommended dose. It doesn’t matter if you have one tube or a 5 gallon bucket. If it’s homogeneous, there are 18.7 mg by weight of ivermectin in 1000 mg of paste.

If I wanted 0.16 grams of paste I’d weigh it on the analytical balance in my lab.

There seems to be a lot of confusion here with units. 1000 micrograms (mcg) = 1 milligram (mg). 1000 mg = 1 gram. 1.0% = 10 mg/gram.

Solutions and dilutions are what I have done for a living for over 20 years.

I wouldn’t take the stuff for horses myself but that wasn’t the question.

[Simkie]

[QUOTE=CrowneDragon;7024418]
Or do you like beef jerky? Maybe you can get Heargard soft chews :D[/QUOTE]

SNORT. HAHAHAHA!

OP, if you want to try this, find out how the actual ivermectin dose your doctor wants you to have–mcg/kg or mcg/lb, whatever–and go from there. Work with her to determine the very tiny dose of liquid ivermectin = that amount, including any dilutions you may need to dose that amount accurately.

Or perhaps have her work with a human compounder, although that’s probably illegal given the availability of the Strombectol?

ETA…when I was looking for a scale that could measure to 0.01 accuracy, I did not find them inexpensive! It’s probably cheaper to use the human drug