With the current opioid overdose epidemic, there has been a LOT of discussion about fentanyl. It seemed to pop up kind of out of nowhere, and has been a major cause of the increase in overdose deaths since about 2012. And it turns out that’s not just a coincidence. Fentanyl is especially deadly because of the specific chemistry of the compound, and the tendency for people who use it illicitly not to know how much they’re taking at once. So in the ongoing fight to reduce opioid overdoses, we need to understand as much as we can about the specific threat of fentanyl, and how we can keep people safe from the dangers it poses.
To be clear, the fentanyl that’s causing so many overdose deaths is illicit fentanyl, which is the kind that is made illegally and not regulated. But to start, let’s explain exactly what the drug is. Fentanyl is an opioid, which is a type of painkiller. It’s in the same class of compounds as opium, morphine, or heroin, but fentanyl is very strong, something between 50 and 400 times stronger than morphine. These drugs are also sometimes called narcotics, but for this video, we’re sticking with the term opioid.
Opioids mainly block pain by binding to something called mu-opioid receptors. These are basically small molecular switches on our nerve cells. Activating these receptors tweaks how easily and how often our nerve cells send electrical signals. Imagine them kind of like volume knobs on your nerves. Activating the receptor essentially turns the volume down. The end result is that the cells are less responsive to stimulation. Less response equals fewer pain signals, equals less pain. And this is often what we want these drugs to do!
Opioids have been used in medicine for a long time. Even fentanyl has been used as a medicine for decades. It was first introduced to the market in the 1960s as an anesthetic. Chemists had been looking for new painkillers that were stronger, safer, and with fewer side effects than previous ones like morphine. One of the ideas was to look for compounds that could dissolve into fat better, the thinking being that this would help them get into the fat-rich central nervous system more quickly. And out of that research came fentanyl.
Fentanyl wasn’t used all that much until the ‘90s, though, when there was a breakthrough in the ways that it could be administered that made it more appealing clinically. It’s still used today for things like surgery, and chronic pain patients can get it in patches or lozenges to help with pain management. But like any incorrectly-used opioid, fentanyl’s effects on the central nervous system, that ability to turn down the volume knob on our nerve cells, can be dangerous.
Opioids can also slow down respiration, since it turns out the same receptor that blocks pain is also found in the cells in the brainstem that control breathing rhythms. The whole process is complex and still being studied, but it looks like opioids also make these cells less responsive to electrical stimulation, slowing down your breathing. And if you keep turning down the volume, well… eventually, you’ll get to no sound at all. What’s more, opioids can also tamp down a second breathing reflex we have to get rid of excess carbon dioxide in our blood. This kind of one-two punch means that if you take too much at once, a person can be in real danger of suffocating.
That said, doctors are aware of this danger and keep it in mind when they write fentanyl prescriptions. The problems come into play when fentanyl is used illicitly or without the supervision of a medical professional. It’s also only dangerous if it gets into your bloodstream. You can’t overdose just from touching or being near fentanyl or any other opioids, despite what you might have heard elsewhere. And to be clear, all opioids have their dangers, not just fentanyl. But fentanyl is particularly dangerous because it’s so much stronger, meaning the dose needed to overdose is much less than for other opioids. Experts say that as little as two milligrams of fentanyl, which is about one tenth of the weight of a penny, can be enough for a lethal overdose. The reason it is so potent is because fentanyl works fast, and binds to mu-opioid receptors in a unique way. Fentanyl is strongly lipophilic, meaning it dissolves well into fats and oils, allowing it to quickly cross the lipid-rich blood brain barrier. This causes it to reach the receptors faster than morphine, and it also forms a different kind of chemical bond that activates the receptor more strongly.
In order to prevent or decrease overdoses of fentanyl, we need to look at ways to mitigate the harm and keep people safe. This could involve providing medical care for people with chronic pain, or addressing the social and medical issues that lead people to use drugs like fentanyl. Additionally, pain management under the supervision of a doctor is critical. Fentanyl is an opioid painkiller that has legitimate uses, but can also be addictive. Its particular chemistry gives it speed and power that most other opioids don’t have, and this spells trouble. To avoid fentanyl overdoses, people should be given resources to screen their drugs for contamination, like fentanyl test strips. Additionally, safe injection sites, which allow people to inject drugs while supervised by medical staff, have been associated with significantly fewer overdoses and deaths from overdoses. Finally, naloxone can be used to reverse overdoses after they happen, and a proof-of-concept study has been conducted into a wearable/injected device that could detect an overdose and automatically administer naloxone. To learn more about how to recognize an overdose, or to find resources about harm reduction and drug addiction, visit the video description. We are grateful to our patrons on Patreon who make it possible for us to take these big swings and create informative, accurate content on all kinds of scientific topics. To learn more about becoming a patron, visit patreon.com/scishow.