Flubendazole shelf life

[brewmaster15]

Hi all,
I wanted to call attention to the shelf life of the dewormer Flubendazole. This dewormer is a good dewormer but hard to get in the United States. It wasn't always that way but it is now. There are some ways to obtain it still... there are sellers on the internet that offer it. I do caution you if you go that route as you don't know the storage and handling of the medication up until you bought it and you have no idea the purity or if somewhere in the supply chain Fenbendazole was substituted..(related but very different drug) . This has implications on its effectiveness which I will mention.
The other way is in products mfg'd overseas. Flubendazole is commonly used in Europe and other areas of the world. Products like " Absolute Aquarium Products" are offered by some discus sellers in the USA and you can buy them online at amazon and ebay. There are many similar products. This dewormer is particularly used often in the koi hobby.

I have always liked flubendazole so I have a habit of researching it which is why I am posting this thread. I have seen alot of discussions in koi circles about shelf life of flubendazole. Many feel its very limited. Nothing hard facts but 1 year shelf is thrown around. .. others say its months once a sealed pack is open. I had a hard time believing that but the more I read the more true it seems.

Even that "Absolute aquarium product"

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Says to use within 3 months of opening.(note..it has multiple ingredients.)

I know of at least one person that used flubendazole to treat confirmed capillaria and it did not work when it really should have. Confirmed by eggs in feces. I have to wonder if that was because the product used was not active anymore.

At this point I'm just posting this as an FYI Maybe Issue.. but I will keep digging and see if I can confirm this and will post if I do. Just thought I should mention it in case members are using it.

Al

[Vanman]

Any other good de-wormers that are easier to get in the USA? I have some new discus in QT and the consensus seems to be that that you always de-worm new discus.

[brewmaster15]

Any other good de-wormers that are easier to get in the USA? I have some new discus in QT and the consensus seems to be that that you always de-worm new discus.

It makes sense to. Reason being by the time you notice a worm problem the fish is losing weight and is in decline. If you deworm all new fish when received its a one and done deal unless you reintroduce worms.

I think alot of hobbyists under estimate the damage worms do. They can literally burrow through tissue leaving tunnels called tracks and they can attack internal organs.

Levamisole is the most accessible dewormer we have here in the USA right now thats effective both in the food or as a bath. Its generally well tolerated and very effective against many worms.

For tapeworms Praziquantel is king.

Another easy to obtain medication is fenbendazole. Some may know it by the trade name Panacur(dog and cat dewormer) its very effective and broadspectrum when dosed in food. It should not be added to the water as Discus do not tolerate it like that.. some fish do..particularly marine fish I believe...but in discus adding it to the water can kill your fish worst case scenario or if lucky cause bad tail standing/head standing and burns.. its really odd how flubendazole only rarely does this to discus when used in the water. I found out fenbendazoles bad side the hardway along while ago.

[mleibowi]

Al- I have absolute wormer plus from cloverleaf and it says must use within 3 months of opening. I find it hard to believe that it will lose activity after 3 months...

[brewmaster15]

I thought so too Mike but its possible. When I used to work.in pharma/biotech some of the compounds he used had very short active dates. There has to be a reason for absolute wormer plus to list 3 months.. my guess is one or more of the ingredients does react with oxygen or moisture and it loses efficacy.

[brewmaster15]

Screenshot_20240115_190829.jpg

https://www.vmd.defra.gov.uk/product...SPC_436885.PDF

https://www.koiforum.uk/archive/index.php/t-17281.html




Discussion where member contacted mfg for shelf life confirmation..

Ok ... received confirmation back from the manufacturer's technical department.

It confirms that Flubenol (flubendazole) is definitely intended to be used in a single shot manner ...

But with very careful storage (airtight, completely dry, air removed if possible and stored in a dark and cold location) they say it "should be" fine for "a" repeat dose .... I am taking that to mean a single repeat dose but they were not going to be held to anything "Unfortunately, not all products have an established broached shelf-life."

Looking at the packaging for dose intervals .... almost all of them are 2 months or less .... so that confirms what Feline said above that the 3 month broached (opened packet) shelf-life expiry for this product is probably even optimistic! ...

There is also the WARNING in the documentation:

"Care should be taken to avoid the following practices because they increase the risk of development of resistance and could ultimately result in ineffective therapy:"

1) Too frequent and repeated use over an extended period of time.

2) Underdosing (which is what will be happening if the product has lost some of it's potency after 3 months).

With this in mind now IMO it should only be relied upon for a one off treatment or course of treatments and the minute it's ineffective immediately stop using it and swap to an alternative treatment.

Reading up more on this it seems that all these treatments are similar in this manner and will eventually lead to them being ineffective which is borne out by loads of cases on different forums. So it would seem to be best practice to maybe alternate quality treatments (with different active ingredients) annually ... you maybe lucky and have prolonged success with a single brand of treatment but a lot of evidence seems to point to it

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[brewmaster15]

More..
Msds tech sheet..
https://www.glpbio.com/flubendazole.html

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[Willie]

If you work at a laboratory setting, they usually have a copy of the Merck Index on a shelf somewhere. That's always been my most definitive source for shelf stability, toxicity, solubility, etc.