Fentanyl (the potent opioid that’s about 50 to 100 times more potent than morphine) is often used in hospitals to treat pain, and it’s getting more and more abused outside of medical settings.
Below, we cover just how it impacts your brain and body system.
What is Fentanyl?
Fentanyl is a synthetic opioid made in a lab to mimic the pain-killing properties our bodies produce naturally.
Fentanyl comes in many forms, from patches that stick on your skin and gradually release a dose of the medication, to lozenges that dissolve in your mouth and get absorbed by your bloodstream, or even a nasal spray or injection for when you need some quick pain relief and it’s mostly for those living with severe pain.
Pharmaceutical-Grade Fentanyl vs Illegally Produced Fentanyl
There’s a difference between what’s made and sold as a medicine and the fentanyl that’s bought illegally. The main differences are:
- Quality control: fentanyl goes through safety checks and is made with regulations in place to ensure it’s safe. This is not the case with illegally produced fentanyl.
- How it’s used: Prescribed fentanyl is for treating serious chronic pain under the care of a doctor. Illegally produced fentanyl is used without any medical guidance whatsoever and can also be mixed in or with other substances, making it very risky to the person using it.
- Safety: Prescription opioids such as fentanyl are much safer because doctors manage their use, and it’s often only prescribed for a short time. Illegal fentanyl is highly dangerous due to its unpredictable strength and purity, and the user consuming it without understanding how too much can easily lead to an overdose.
What Do You Need To Know About The Effects of Fentanyl?
When fentanyl gets into your body, it moves fast to latch onto parts of your brain and body called opioid receptors. These opioid receptors are a key part of your body’s own system for dealing with pain, pleasure and even certain kinds of behaviour. And because fentanyl’s very potent, it can provide intense pain relief.
Fentanyl’s Impact On Your Central Nervous System
Fentanyl works its way into your central nervous system – that’s everything from your brain down to your spinal cord.
GABA’s a chemical that acts as the brakes for your brain activity. So when fentanyl boosts GABA levels, you end up feeling very drowsy. You might even get so drowsy that you find it hard to stay awake for more than a few minutes at a time.
Respiratory Depression
One of the most serious effects of fentanyl is how it slows down your breathing.
Fentanyl affects the part of your brain that controls automatic functions like breathing. When carbon dioxide levels in your blood rise, your brain will naturally tell your body to breathe more. Fentanyl reduces this signal, so your breathing slows down and becomes shallow.
Other signs of respiratory depression include:
- Slow breathing: A significant reduction in the rate of breathing, less than 12 breaths per minute.
- Weak pulse: A slowed-down pulse may be a sign of respiratory depression.
- Shallow breathing: Breaths may become very shallow, with minimal chest movement.
- Cyanosis: A bluish tint to the lips, skin, or nails due to lack of oxygen.
- Irregular breathing: Breathing patterns will start to become erratic or include gasping for air.
Respiratory depression is a strong sign of an opioid overdose, which means that medical attention is urgently needed.
Cardiovascular Effects
Fentanyl can also significantly impact overall cardiovascular health.
It can slow your heart rate down (a condition known as bradycardia) and give you low blood pressure – or hypotension for short.
Slowing down your heart rate can have another serious effect, reducing the amount of oxygen getting pumped around your body and potentially leading to serious problems with your internal organs. And when your blood pressure drops, which can happen with hypotension, your organs won’t get the blood pressure they need to function.
Psychological and Behavioural Effects
Fentanyl can also give you a rush or feeling of pure happiness, which is mainly down to the way it affects the brain’s reward system. It’s a big part of why fentanyl’s so addictive as users are always chasing that high.
Over time, this can lead to some pretty intense anxiety and depression too. The changes it makes to your brain chemistry can leave you feeling hopeless, anxious and detached from reality.
The Fentanyl Fold and Why Fentanyl Users Slump Over
You may have seen people who are on fentanyl end up in a bent-over position for no apparent reason – they call it the fentanyl fold. This is actually common when fentanyl has taken hold. What happens is that fentanyl makes you so drowsy that you can’t stay upright, but at the same time you’re still conscious for a while.
Fentanyl is a serious sedative. When you take it, you get really drowsy, your breathing gets slow, your heart rate and blood pressure drop, your muscles go slack, and it comes with an intense feeling of euphoria. And it can also make your body feel heavy and hard to move, just like with other strong sedatives. What it does is basically numb your brain, and your muscles feel relaxed enough to make standing up straight feel difficult.
You’ll often see people in this position if they’ve taken too much. It can be a warning sign that they may be on the verge of an overdose.
If you see someone who is slumped over, especially if they’re not responding, treat it like it’s an emergency. Call an ambulance, use naloxone if you have it, and stay with them until help arrives.
Xylazine and How It’s Contaminating Fentanyl
More and more of street fentanyl is being laced with xylazine, a veterinary sedative that’s known as the street name ‘tranq’. Naloxone doesn’t work on xylazine, and people who keep using it can cause necrotic skin wounds, regardless of whether they’re using clean needles or not.
Xylazine was a bit of a non-entity in the UK for a while, unlike the US, however, it’s no longer just a US only issue. We saw the first UK death linked to it in 2022, and since then it’s been found in the UK and Scottish drug markets. We’ve even seen it in samples sold as heroin or ketamine. As a result, the UK government has put xylazine on the list of Class C drugs, under the Misuse of Drugs Act – which came into effect as of January 2025.
What this means for you or someone you know who’s using fentanyl or opioids off the street:
- Don’t count on just naloxone. Xylazine isn’t an opioid, so naloxone isn’t going to reverse it. However, health experts still recommend giving naloxone in an emergency.
- Xylazine is linked to open sores that can appear even in places that aren’t getting injected with drugs, and they won’t heal. People often think it’s because of a hygiene issue, when in reality the real cause is the xylazine.
- Xylazine gets added to fentanyl or heroin to make it go further – and users are often in the dark about what’s really in their supply.
Reach Out for Support Today
If you or someone you care about is using this substance recreationally, it might be time to reach out for support. Like all opioid drugs, fentanyl is very dangerous, and the chances of an opioid overdose are high.
We can help you find the right support, help you manage the withdrawal symptoms and get back into a place where you’re free from active addiction and opioid dependence. Please call us today on 03301 596 494 to find out more about how we can help you.
