I wanna be sedated.
Heroin, Fentanyl, Endone, Codeine, Morphine, Oxycontin, the list goes on – there’s a load of opiates out there that people use for analgesia, for recreational use, and for abuse. The media is prepared to frighten you with articles about overdoses killing more and more each year (and to be fair, it is a big problem), but how does it kill you? Is Narcan (Naloxone) the silver bullet? Do they really wake up swinging? Here are the answers.
How Opioids Work
An opioid is simply a substance that binds to the opioid receptors in the body. There are about 5 types of receptor. When an opioid binds to the site (whether that’s heroin, fentanyl, or whatever else) it triggers a response from the tissue – the response varies based on the receptor. Most receptors trigger analgesia – pain relief – but can also affect mood, appetite, nausea, gastrointestinal motility (often manifesting as constipation), sedation, and miosis (pupil constriction). Your body has some natural opioids that it secretes for various functions, which is why we have these receptors in the first place.
For our purposes the most important receptors are the mu-receptors, because they are targeted by drugs like morphine, fentanyl, and heroin (also known as diamorphine). Three subtypes in particular are responsible for causing the observed effects:
- Mu-1: Analgesia and physical dependence
- Mu-2: Respiratory depression, pupil constriction, euphoria, reduced gastrointestinal motility, and physical dependence
- Mu-3: Vasodilation (dilating of the blood vessels which drops blood pressure)
So when someone injects heroin and it floods their system, the heroin binds to the various mu opioid receptors and causes a reduction in pain and analgesia as the beneficial effects, along with a host of negative side effects. A lot of this is ultimately drug and dose dependent, as well as frequency of use.
In the therapeutic environment, opioid administration is titrated against effect. That is to say, we give it in doses and frequencies to maximise its beneficial effect (usually analgesia) and to minimise its side effects (vasodilation, respiratory depression, and dependence). Most people who receive therapeutic opioids do not become addicted to them when taken as directed or when administered by healthcare professionals – you don’t suddenly become a heroin addict because you got 5mg of morphine in the back of the ambulance. But the doses that we give these drugs at tend not to induce the euphoria that recreational users are ultimately searching for (well, outside of ‘my pain is gone, yay for me.’)
Different opioids have different properties – they aren’t all equal even if they all have the same intended therapeutic benefit. For example, fentanyl is much more potent than morphine – 2.5mg of morphine would be equivalent to about 25mcg of fentanyl (or 2500mcg of morphine, if you’re bad with metric measurement).
How do they kill you? When given in excessive amounts, opioids have a sedative effect. This is why you can become sleepy when taking these medications. The major problem with this is respiratory depression, which means that they start to inhibit your natural drive to breathe. The respiratory rate and depth decrease with higher doses – and obviously if you don’t breathe, you don’t flush out carbon dioxide and you don’t bring in oxygen, and you die. On top of that, opioids can induce nausea and vomiting, and combined with their sedative and resultant muscle-relaxing effect, there’s a major risk of aspiration – where stomach contents escape up the oesophagus and down into the unprotected airway.
(As an aside, some opioids, like fentanyl, are used for sedation in some settings – but this is under close critical care situations)
So someone who dies from a heroin overdose has two pathways they can ultimately go down (to oversimplify). First, they overdose – causing coma, respiratory depression often to the point of apnoea (not breathing), and possible aspiration. For many, they just die like that – because nobody finds them in time to provide resuscitation. Alternatively, someone does find them, but they later die from complications (like aspiration pneumonia). If they don’t die, they can vary from complete recovery (with prompt care and attention) to major disability (the brain doesn’t tolerate hypoxia, or low oxygen levels, very well at all).
How We Fix It
Everyone knows about Narcan (naloxone) but it isn’t quite as simple as it sounds. Narcan is an opioid antagonist – it binds to the opioid sites much more competitively than opioids, effectively replacing them – but it doesn’t actually trigger any of the effects that opioids do. Think of the opioid as a key – the key goes into the door and unlocks the doorway to its effects. Narcan is sort of like jamming a key into the lock and then snapping it off, so that you can’t turn it and thus the door is closed.
In opioid overdoses, giving Narcan effectively reverses the effects, and quite rapidly – this is why you’ve seen people suddenly wake up after they get the Narcan. There are two issues with it – namely that it only blocks the opioids, and it might not last as long as the circulating opioids. We’ll tackle this latter issue first, because it’s easier to understand. All drugs are metabolised (broken down) and excreted, and after a certain amount has been metabolised, they stop having an appreciable effect. Some opioids can outlast Narcan – thus, while the Narcan may have been metabolised and is now ineffective, there’s still plenty of opioid left just waiting to bind, and the patient can go back downhill again.
The other issue with giving Narcan without thought comes from failing to correct hypoxaemia (low oxygen in the blood) and hypercapnia (high carbon dioxide levels). When we roll up on a scene with a heroin overdose, our first goal isn’t to slam them with Narcan – rather, we do a few important basics first:
- Ensure they actually have a pulse (if they don’t, they need CPR above all else)
- Secure an airway – the pipe needs to be clear so that we can push air down there. That also means getting rid of as much vomit as we can (though we can’t suction very far).
- Determine if they are breathing effectively – and if not, start breathing for them
- Quickly check their neurological status to see how out of it they are, and to confirm suspicions of opioid overdose
- Complete a full assessment including oxygen saturations, end tidal capnography, blood pressure, electrocardiogram, and so on
So let’s say that we’ve got a typical heroin overdose – usually the kind that isn’t found for a little bit before someone raises the alarm. We roll up and find out her oxygen saturations are 75% (normal is over 94%) and an End Tidal CO2 of 55mmHg (normal is 35 to 45), with a respiratory rate of 8/min (woefully inadequate, minimum is around 10 to 12 depending on depth of breathing for most people), a heart rate of 80, and a blood pressure of 80/40 (quite low). Giving this patient Narcan straight up would bring her around, but it can do a few other things:
- Make her confused and agitated due to the hypoxia. People often say that they wake up angry because ‘we’ve taken away their high’ but it’s usually because they’re hypoxic. Hypoxia causes confusion and agitation – your brain needs a constant supply of oxygen to work properly, and when it doesn’t get that, it starts to malfunction, resulting in confusion and agitation.
- Trigger a sympathetic (stimulant) reflex response from the withdrawal – pushing up her heart rate, blood pressure, and agitation. The body tries to compensate for its new-found hypoxia by triggering its normal response, which might not be beneficial in her case when she’s already agitated. In rare cases, there might be a pulmonary oedema or arrhythmia response (fluid in lungs or heart not beating properly) – but the mechanism for pulmonary oedema is unclear, and serious side effects are uncommon.
- If she has already aspirated, she’s not going to compensate very well now that she’s woken up hypoxic and agitated. Aspiration pneumonia is especially nasty – gastric contents are acidic and destroy lung tissue easily, not to mention the fact that it’s a cocktail of bacteria, acids, food, and whatever else went down there. She’s now trying to desperately breathe through a load of crap in her lungs, and it isn’t going to work very well. She’s going to have to go on non-invasive ventilation, which is difficult to tolerate when you’re panicking and can’t breathe, or be sedated and ventilated, and we’re back where we started!
So before we give Narcan, we need to fix the secondary problems – namely by ventilating her. We do this by inserting an airway to keep her own airway patent, and then using a bag connected to an oxygen supply to ventilate her. We’re basically forcing air down into her lungs, which is the opposite way that we breathe normally. By breathing for her, we increase her oxygen saturations, and blow off excess carbon dioxide, reversing the problem caused by the overdose. Her blood pressure may be counteracted by giving her intravenous fluids, or by using a vasopressor if needed.
Once we’ve improved her oxygen and carbon dioxide levels, then we might look at Narcan. How much is given will depend on what is deemed clinically appropriate. For some patients waking them up is undesirable – consider the patient with extensive aspiration, where waking them up is basically pointless if they end up on a ventilator anyway. For those that have been easily corrected though we can start to introduce it to restore their own ventilatory drive – so that they start to breathe on their own, even if they don’t completely wake up. At the end of the spectrum we can just wake them up entirely, if there are no concerns over complications or vital signs.
From here, we’ve got two options:
- Transport to hospital. In almost every case we’re going to push for this, just in case something goes wrong once we leave.
- Leave them at home. This is almost always going to be a ‘refusal against advice’ situation, where we’d have to make sure they adequately understood the risks of being left at home (namely, that the Narcan wears off and the opioid takes over again). Even then, the only time I’d be ‘happy’ with someone staying at home against advice is if it’s an uncomplicated fix (e.g. they were breathing a little slow but otherwise okay, and I woke them up with Narcan and nothing else), and someone was there to watch them.
How can you help?
In some countries the general public now has access to Narcan, usually as an intra-nasal device (e.g. squirting it up the nose). So should you give it? Should you still call an ambulance?
- First and foremost, it’s important to call an ambulance, and to be honest about what’s happened. None of us give a shit that you use heroin or fentanyl or whatever else. It’s your own personal choice. But playing coy does nothing except waste time, and I will eventually figure out what’s happened (I probably have a strong suspicion within the first minute of getting on scene).
- If they aren’t breathing, start CPR – people are generally bad at finding pulses, especially when under pressure, so don’t rely on it as a marker of whether they’re in cardiac arrest or not. Administer rescue breaths if you want to (if you don’t, that’s fine – but at least start CPR).
- If they are breathing but drowsy or unresponsive, roll them on their side and make sure their airway is clear (scoop out any vomit in their mouth).
- If you have access to Narcan and were taught how and when to use it, you can give it. It’s probably safe to give. There are potential side effects, but they are typically uncommon, and preferable to death, which is permanent.
In short: if they aren’t breathing do CPR, if they are put them on their side, and give Narcan if you have it and have been taught to use it. Even if they wake up all the way it’s still worth calling an ambulance in case they experience any side effects/complications. The worst that can happen is that the crew turns and and is turned away by the patient.
To conclude: There are very good reasons why we don’t just slam somebody with Narcan when we rock up at a heroin (or fentanyl) overdose, but Narcan is probably saving lives when it is given early on by bystanders. It isn’t quite as simple for us as giving Narcan and standing back to watch the show, but it is one of our major considerations.