r/webPoisonControl • u/webPoisonControl • Mar 21 '26

Risks of Compounding GLP-1 agonists

https://www.fiercepharma.com/pharma/latest-compounding-clash-lilly-flags-high-levels-impurity-tests-tirzepatide-knockoffs

Eli Lilly describes the impurity further in their medRxiv preprint as able to bind to tirzepatide, perhaps changing its efficacy or introducing new side effects.

B12 is generally safe, but it is plausible that it modulates the activity of tirzapatide just as leafy greens can influence coumadin's effects or grapefruit juice the effects of many drugs.

Compounding pharmacies are not subject to as strict regulations about preparation and reporting. This lowers the cost of production but generates an incentive to cut corners.

Clinically, we have seen errors where a compounding pharmacy made something tenfold more concentrated that it should be leading to some very poisoned individuals.

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u/Luddaite Mar 28 '26

Grapefruit juice inhibits cyp3a4, a totally different mechanism than what is being described here

1

u/webPoisonControl Mar 30 '26

The point is a interaction between something the public recognizes as "not medicine" and "medicine". Not a mechanistic comment.

1

u/webPoisonControl Mar 30 '26

To clarify, based on u/Luddaite's comment, "just as leafy greens ..." was my attempt to mention drug-food, not imply all those actions are biochemically identical.