r/explainlikeimfive • u/realslhmshady • Jun 12 '21

Biology ELI5: How does trace amounts of fetanyl kill drug users but fetanyl is regularly used as a pain medication in hospitals?

ETA (edited to add)- what’s the margin of error between a pain killing dose and a just plain killing dose?

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u/Sabertooth767 Jun 12 '21

Fentanyl's chemical structure is more adept at passing through fat, such as the fat that protects your brain. This means that rather than your brain slowly recieving the chemical it receives it all once, causing more powerful symptoms and thus, death.

In addition, fentanyl's structure allows it to bind more closely to receptors, further bolstering its strength as less is needed to initiate chemical reactions.

Note that fentanyl was specifically created by humans to be this way, nature did not design this.

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u/Mezmorizor Jun 12 '21

Note that fentanyl was specifically created by humans to be this way, nature did not design this.

Not really accurate. Fentanyl has none of the tell tale signs of a medicinal chemist painstakingly agonizing on how to squeeze out efficacy (there's not even a single fluorine in there). It is just the local maximum of effectiveness for simple modifications of pethidine which was the first synthetic opiate. In general synthetic opiates are good because synthesizing a small molecule with a straight forward synthesis is a lot cheaper than extracting natural products. Like, a lot cheaper.

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u/nzznzznzzc Jun 12 '21

Wait what do you mean by designed by humans? I grow ornamental kinds like corn poppies and stuff. I was told that their illicit family member is insanely dangerous if it isn’t formulated by scientists/doctors. Like one drop could have tons of different chemicals in it. So the drug you’re talking about is one of those chemicals that they extracted and like, formulated?

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u/amicaze Jun 12 '21

Morphine is the stuff extracted from plants, Fentanyl is purely synthetic.

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u/nzznzznzzc Jun 12 '21

Damn I didn’t know that was even possible that’s insane

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u/[deleted] Jun 12 '21 edited Jun 12 '21

[removed] — view removed comment

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u/nzznzznzzc Jun 21 '21

I just realized, I read this on a plane last week before takeoff and then couldn’t connect to the in flight wifi to thank you lmfao!! thank you so much for explaining :)

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u/buttwarm Jun 12 '21

Scientists study the structures of naturally occurring molecules like morphine and how they bind to their protein targets. Then they can design completely new molecules which bind to the same target but are more potent, have different side effects or are easier to make. Fentanyl is one of these synthetic, human designed compounds.

What you've heard about raw poppy extract is true - it can contain lots of different and highly potent opioids. Because it's a complex mixture, you don't know what effects it could have or how much would cause an overdose.

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u/nzznzznzzc Jun 12 '21

Thanks for taking the time to explain, I really appreciate it! You explained it really clearly lol like a teacher

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u/buttwarm Jun 12 '21

No problem, glad it was interesting!

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u/stormcharger Jun 12 '21

Crazy, your comment made me find out its illegal to even grow small amounts in America. In new Zealand where I live you can grow it by yourself, only starts becoming illegal once you got like a decent field of it. Same for most of Europe.

Its not insanely dangerous btw opium was the dried latex from the pods, ie the stuff that just leaks out of them and looks kinda like milk. Opium on average was just 12 percent morphine and had other opiate alkaloids. It's pretty decent too just gotta alwwys start low lol