Normally, your body is a delicately balanced chemical system.
Taking extreme amounts of a drug can throw it so far off balance that it can’t recover
on its own.
That’s called overdosing.
There are lots of ways to overdose.
The overdoses you’re probably most familiar with involve your brain.
Your body uses chemicals called neurotransmitters to send messages like “move your hand!”
or “keep pumping blood!”
These messages are sent between neurons--cells you’ll find in your brain, spinal cord,
and peripheral nerves.
Neurotransmitters from neurons are released into a space between cells, called a synapse,
and then bind to receptors on another cell.
Think of a synapse like a traffic light.
Basically, depending on the neurotransmitter and the receptor it binds to, the stoplight
will either turn red or green.
With a red light, traffic stops and your neurons quit firing.
When the light turns green, traffic moves full speed ahead and the neuron fires--sending
a chemical message like “muscle, contract!”
Your body’s goal is to keep traffic flowing without causing an accident.
Overdoses are, for the most part, different for every drug.
And the severity of the overdose is affected by how much of the drug is taken, what other
drug it could (knowingly or unknowingly) have been cut with, and if it was taken in combination
with anything else.
Depressants give your neurons the red light.
They depress your central nervous system, so your neurons aren’t firing as much, and
your senses are dulled.
At best, you fall asleep, at worst… you stop breathing.
Chances are you’re familiar with one readily available, easy to procure depressant: alcohol.
And blacking out during a night of drinking /would/ qualify as an overdose.
Normally, a neurotransmitter molecule called gamma-Aminobutyric acid, better known as GABA,
binds to its receptor on a neuron and stops the neuron from signaling to other cells.
GABA makes your neurons chill out.
Alcohol molecules can do a bunch of things and one of those things is binding to GABA
receptors so they’re getting that stop light even more often and your brain slows waaay
down.
When there’s too much alcohol in someone’s bloodstream they become dehydrated and can
lose consciousness.
The losing consciousness part is often the riskiest aspect of an alcohol overdose--it
means the person overdosing won’t be able to respond when they, say, start to throw
up and choke, or they won’t be aware of dangerous environmental factors--like freezing
temperatures.
If someone’s overdosing they need to seek immediate medical attention, which could include
a tube to help with breathing, and an IV to help with dehydration.
Benzodiazapenes, or benzos, are also depressants that turn that traffic light red.
Valium, Xanax, and Klonopin are examples, and they’re all commonly prescribed for
anxiety, insomnia, and seizures.
Benzos bind to the GABA-A receptor, one type of GABA receptor, locking it into a shape
that helps the GABA neurotransmitters bind better than they normally would.
If someone has overdosed on benzos they’ll be really, really out of it and might experience
memory loss of anything that happened after taking the benzos.
During a severe overdose, they’ll likely be put on a respirator to help them breathe
until their body metabolizes the drug.
Another option is the antidote flumazenil, but it’s a risky move because the person
overdosing can experience acute withdrawal and that can cause seizures.
And, unfortunately, the standard treatment for seizures is… the drug they’re overdosing
on: benzos.
So yeah, kind of a catch-22.
Depressants can be really dangerous, but opioids might be even more so.
Opioids aren’t technically categorized as depressants, but they have similar qualities
and give your neurons that red stoplight.
Opioids [onscreen: Morphine, heroin, fentanyl.
Then bring in red traffic light] affect your central nervous system more than benzos, which
means overdose victims often die because they stop breathing completely.
Opioids act on opioid receptors--different than GABA receptors, but similar in effect.
Fentanyl acts on the mu opioid receptor, and it binds to it faster and more tightly than
heroin.
You can treat an opioid overdose using naloxone, also sold as Narcan, which knocks the opioid
molecules off their receptor.
In rare cases giving a large dose of naloxone to someone who’s overdosed can cause severe
withdrawal.
So now we’re flipping to the other side of the coin--the “green means go!” side:
stimulants.
Stimulants get your neurons firing.
A lot.
And too much firing can be reaaally dangerous.
Like, heart attack dangerous.
For a well-known stimulant look no further than the caffeine in your morning cup of coffee.
But coffee’s got nothing on cocaine and methamphetamine.
Most stimulants stop your cells from reabsorbing noradrenaline and dopamine, two neurotransmitters
that keep your neurons firing and give you that happy, upbeat feeling.
When they build up in your body that causes heart and central nervous system overstimulation.
Methamphetamine use can lead to muscle breakdown in part because the person on the drug is
moving so much.
That breakdown increases products like creatine phosphokinase, which is toxic to your kidneys
and can cause them to fail.
There aren’t many treatments for stimulant overdose, but one option is actually to sedate
a person by using benzos-- making the green light turn yellow or maybe even red.
Of course, overdoses can affect more than just your brain.
For example, acetaminophen (aka Tylenol) is metabolized in your liver, and if you take
too much of it its toxic byproducts can’t be broken down and will start killing liver
cells.
So, hopefully we’ve made it clear that overdosing isn’t a one size fits all event.
People can overdose on things that are addictive, like heroin, or not addictive--like Tylenol.
Either way, if you suspect that someone is overdosing, call 911.
Stay safe and see ya next week.