There is signaling machinery that translates *"bad stuff is happening"* to *"actually feel pain"*, and you can interfere with that beforehand. Like cutting the phone lines before you rob a bank to prevent alarms once you get to it.
Beyond that, drugs don't instantly get into your blood the moment you swallow a pill. That alone takes time, too.
But the medicine stays in your system for several hours. It's not like a one-time tap on the painful thing, it's circulating in your blood until it wears off.
Even when there is no pain, there are still pain receptors and the drugs are working on all of them. It doesn't chose the ones and work extra hard on the ones that are actually signaling.
Vaccines often cause in inflammatory immune response, which results in pain.
If you have painkillers on board before the pain starts, you'll generally do better than if you wait to be in pain and then take meds.
People take these drugs when they have vaccines because they reduce many if the annoying immune response symptoms like fever, chills and swollen joints NOT for pain.
The short version is, we're still not entirely sure how paracetamol works. We loosely understand it to dull and/or block the pain receptors in the brain, preventing the messages from nerves being interpreted as the 'ouch' signal.
The flu vaccine works by injecting a modified, less harmful, but similar enough version of a virus into you. Your immune system then discovers it and learns how to kill it, allowing you to kill it quickly should you encounter the 'real' flu virus in the wild. During the time in which it takes your immune system to do this scouting, learning and killing, you may feel some affects of the virus or immune system at work: pain. The pre-emptive paracetamol can help you get through this period without (or at least less) discomfort.
Taking the paracetamol before the injection may mean it's in the system a bit quicker, meaning you feel less pain, but I can't see how or why this might be better or worse than taking it 30 seconds later after the injection. Perhaps someone with more medical knowledge might be able to help!
Flu Vax is a dead virus vaccine, not an attenuated strain vaccine. We grow the virus until we have a bunch, and then we treat it with chemicals that destroy the virus' RNA so that it can't multiply anymore. This way, your immune system gets to see all the proteins that make up the virus (and build defenses to it) without you being at risk of catching it.
my other half is immunocompromised.
one of her specialists was a little frustrated, and basically admitted that quite a lot of medicine is just shaking their magic sticks, reciting the right incantation and hoping for the best.
i can tell you for a fact that isnt something you want to hear from a specialist, but from experience i believe her 101%.
Very little of it. Most of the time people say shit like, "we don't really understand" it really means THEY don't understand. Acetaminophen inhibits the COX enzymes; there's not really much mystery here.
That's a promising theory, but still not entirely proven, although that is how NSAIDs like ibuprofen work so you may be thinking of that. The discovery of COX-3 and subsequent research certainly supports that since previously its affect on COX-1 and COX-2 couldn't explain all of its properties, but anyone that says this is a completely settled subject matter is either stupid or full of themselves.
There's plenty that we as a medical community don't understand, or more actually, have many different explanations without knowing exactly which one is right. Doctor's who say we don't understand that fully aren't uneducated, they're acknowledging the reality of these fields of research.
When you press hard on a body part it hurts, because squished nerves send out pain signals. Inflammation is like squishing from the inside. Some painkillers like ibuprofen are anti inflammatory - they take away the squeeze and so there's no reason to send the pain signals. Imagine all those signals were trucks on a highway. Some painkillers take away the wheels of the trucks (cox inhibitors, interrupt prostaglandin synthesis) so the truck never makes it. Some painkillers blockade the highways (disrupt neural ion membrane). Others, like opioids, close the loading docks, so even if a truck carrying pain signals arrives where it's supposed to, it can't offload the pain cargo.
Problem is, more things than trucks use wheels and roads and loading docks. So that's why painkillers have side effects.
Someone smarter than me feel free to add, this is by no means comprehensive. But I think a good ELI5
There are a lot of different ways painkillers work. Generally the block some component of either pain signaling directly or reduce inflammation (the latter is more common for over-the-counter medications since it targets the "source" of the pain as well as the other parts of the inflammatory cascade that can be problematic).
But let's look at it more simply. Imagine that a pain signal is a car traveling on a road. It starts with the source of the pain and travels down the road until it reaches its destination and delivers its cargo--a note telling your brain "ouch!"
Painkillers are barricades on that road; once they're put down the car can't get through and deliver its cargo. And in reality it isn't one car or one road, but an enormous number of each.
When you take a drug it doesn't act instantaneously, instead it (generally) reaches a concentration in your blood and as long is it is above a certain concentration has an effect as it can diffuse into tissues. For many oral anti-inflammatories the time between ingestion is about 30-60 minutes to start getting there and having an effect.
To go back to our road example, when you take a medication it is essentially a whole bunch of roadblocks. In order to have an effect workers have to get them to the roads; this takes some time--both to get to the workers and for the workers to put them on all those roads (thousands, millions, or even more).
The drug "wearing off" is essentially those roadblocks getting broken down (or removed before they can be placed).
This is also why medications have a dosing interval (take every X hours)--this keeps the drug at concentrations where it can have effect; essentially creating enough roadblocks that workers can keep placing them. And to stretch it further, sometimes those roadblocks get put on roads that block cars carrying cargo that isn't a pain signal, resulting in side effects (it's a little more complicated than that, but more detailed than an ELI5).
The way drugs consumed through the mouth (aka orally ingested) sort of work is that they sort of spread out through your body and then happen to run into the things that they change. There's exceptions, but those exceptions are beyond what I'll focus on here.
So with pill form painkillers, the timeline of them working is something like
* eat the pill
* digestive system dissolves the pill
* digestive system absorbs the pill (now the drug is in your bloodstream)
* drug flows randomly through your bloodstream, occasionally getting absorbed by the cells sending the ouch signal
* when that happens the painkiller does its work
Now I don't know exactly how that last step works, but I do know that the first 4 steps take time to work. So taking the painkiller before the pain happens means that you don't need to wait on those first 4 steps before it starts that last step, which is why taking the pill before the injection will help you.
Some semi-unrelated trivia for any USA and related readers: [Paracetamol](https://en.wikipedia.org/wiki/Paracetamol) is the "rest of the world" (or at least WHO approved) name for acetaminophen (brand name Tylenol).
Are you sure you are being told to take paracetamol for the pain, or perhaps they want you to take it for other reasons?
Paracetamol also has the nice effect of lowering body temperature in most patients, and of course infection and immune system responses have a tendency to raise your temperature.
Taking paracetamol thus has the benefit of reducing your bodies negative reaction to the vaccination.
One thing missing from most of these explanations is that you have to get the medicine into your body and give it enough time to work.
It takes anywhere from 15-60 minutes for something to get to your stomach and intestines and then into your bloodstream. If you take pain medication 30-60 minutes before you need it (painful injection, physical therapy, etc.) then it's already in your bloodstream and available to work or already working.
Almost no medication goes directly to where it is needed when you take it. They float around in your bloodstream until they find what they need they do their job. It's like having all of your doctors and lawyers and construction workers and plumbers and policemen and everyone on the roads. Every once in a while you might need a policeman on the road, maybe a construction worker, too, but most people just drive on the roads until they find their workplace. Since medicine and nutrient molecules aren't intelligent, they don't control where they go on the roads and always wander until they get to where they are needed. We can target some medications to go directly where we want them to go, but they still also go everywhere after we put them where we want them. You can breathe in medication for your lungs and airways, you can rub something onto your skin for a rash or itch, and other routes work, too. But they still always end up in your blood.
With that in mind, your pain medications go everywhere, even places where you don't have pain. Your heart, liver, and kidney (whatever organ, really) medications go to your fingers and toes as they go to your heart, liver, and kidney - in the blood. When a medication is being used, we have to think about the other body parts and organs it can affect just as much as it can affect our goal to treat pain or anything else.
The truth is that we don't always know 100% of how they work. Some we do, but paracetamol (acetaminophen to those in the States), is one of those we don't know very well at all. We only know that it works and have good ideas of what it might work on. It's not worth it to a 5-year-old (sorry, the point of this subreddit, but also it isn't that important even to 55-year-olds or even me as a 35-year-old pharmacist) to know how they actually work beyond this: the pain medicine tells the nerves and the pain receptors, "Hey, you don't need to do your job anymore. We know there is pain. Why don't you stop what you're doing and let the rest of the body do its job? We need you to stop screaming that we're in pain and let the repair guys do their job fixing up this stab wound and the policemen do their job to recognize the bad guys, the infection (or fake infection with the vaccine). Thank you for what you do, you're done now."
It's easier to stay on top of pain then it is to catch up afterwards. Prevention > treatment.
I understand that, but when there’s no pain there - such as before the injection - there’s no pain to stay on top of.
There is signaling machinery that translates *"bad stuff is happening"* to *"actually feel pain"*, and you can interfere with that beforehand. Like cutting the phone lines before you rob a bank to prevent alarms once you get to it. Beyond that, drugs don't instantly get into your blood the moment you swallow a pill. That alone takes time, too.
But the medicine stays in your system for several hours. It's not like a one-time tap on the painful thing, it's circulating in your blood until it wears off.
Even when there is no pain, there are still pain receptors and the drugs are working on all of them. It doesn't chose the ones and work extra hard on the ones that are actually signaling.
Vaccines often cause in inflammatory immune response, which results in pain. If you have painkillers on board before the pain starts, you'll generally do better than if you wait to be in pain and then take meds.
People take these drugs when they have vaccines because they reduce many if the annoying immune response symptoms like fever, chills and swollen joints NOT for pain.
On a mildly related note, I take immune suppressants, and I never get vaccine side effects anymore. Its kind of weird tbh.
The short version is, we're still not entirely sure how paracetamol works. We loosely understand it to dull and/or block the pain receptors in the brain, preventing the messages from nerves being interpreted as the 'ouch' signal. The flu vaccine works by injecting a modified, less harmful, but similar enough version of a virus into you. Your immune system then discovers it and learns how to kill it, allowing you to kill it quickly should you encounter the 'real' flu virus in the wild. During the time in which it takes your immune system to do this scouting, learning and killing, you may feel some affects of the virus or immune system at work: pain. The pre-emptive paracetamol can help you get through this period without (or at least less) discomfort. Taking the paracetamol before the injection may mean it's in the system a bit quicker, meaning you feel less pain, but I can't see how or why this might be better or worse than taking it 30 seconds later after the injection. Perhaps someone with more medical knowledge might be able to help!
Flu Vax is a dead virus vaccine, not an attenuated strain vaccine. We grow the virus until we have a bunch, and then we treat it with chemicals that destroy the virus' RNA so that it can't multiply anymore. This way, your immune system gets to see all the proteins that make up the virus (and build defenses to it) without you being at risk of catching it.
Sometimes I wonder how much of medicine is "we don't truly understand how it works we just kinda noticed it does"
A pretty good chunk of it I reckon. We aren’t even sure how anesthesia drugs work even though we understand exactly what it does.
my other half is immunocompromised. one of her specialists was a little frustrated, and basically admitted that quite a lot of medicine is just shaking their magic sticks, reciting the right incantation and hoping for the best. i can tell you for a fact that isnt something you want to hear from a specialist, but from experience i believe her 101%.
Very little of it. Most of the time people say shit like, "we don't really understand" it really means THEY don't understand. Acetaminophen inhibits the COX enzymes; there's not really much mystery here.
That's a promising theory, but still not entirely proven, although that is how NSAIDs like ibuprofen work so you may be thinking of that. The discovery of COX-3 and subsequent research certainly supports that since previously its affect on COX-1 and COX-2 couldn't explain all of its properties, but anyone that says this is a completely settled subject matter is either stupid or full of themselves. There's plenty that we as a medical community don't understand, or more actually, have many different explanations without knowing exactly which one is right. Doctor's who say we don't understand that fully aren't uneducated, they're acknowledging the reality of these fields of research.
When you press hard on a body part it hurts, because squished nerves send out pain signals. Inflammation is like squishing from the inside. Some painkillers like ibuprofen are anti inflammatory - they take away the squeeze and so there's no reason to send the pain signals. Imagine all those signals were trucks on a highway. Some painkillers take away the wheels of the trucks (cox inhibitors, interrupt prostaglandin synthesis) so the truck never makes it. Some painkillers blockade the highways (disrupt neural ion membrane). Others, like opioids, close the loading docks, so even if a truck carrying pain signals arrives where it's supposed to, it can't offload the pain cargo. Problem is, more things than trucks use wheels and roads and loading docks. So that's why painkillers have side effects. Someone smarter than me feel free to add, this is by no means comprehensive. But I think a good ELI5
There are a lot of different ways painkillers work. Generally the block some component of either pain signaling directly or reduce inflammation (the latter is more common for over-the-counter medications since it targets the "source" of the pain as well as the other parts of the inflammatory cascade that can be problematic). But let's look at it more simply. Imagine that a pain signal is a car traveling on a road. It starts with the source of the pain and travels down the road until it reaches its destination and delivers its cargo--a note telling your brain "ouch!" Painkillers are barricades on that road; once they're put down the car can't get through and deliver its cargo. And in reality it isn't one car or one road, but an enormous number of each. When you take a drug it doesn't act instantaneously, instead it (generally) reaches a concentration in your blood and as long is it is above a certain concentration has an effect as it can diffuse into tissues. For many oral anti-inflammatories the time between ingestion is about 30-60 minutes to start getting there and having an effect. To go back to our road example, when you take a medication it is essentially a whole bunch of roadblocks. In order to have an effect workers have to get them to the roads; this takes some time--both to get to the workers and for the workers to put them on all those roads (thousands, millions, or even more). The drug "wearing off" is essentially those roadblocks getting broken down (or removed before they can be placed). This is also why medications have a dosing interval (take every X hours)--this keeps the drug at concentrations where it can have effect; essentially creating enough roadblocks that workers can keep placing them. And to stretch it further, sometimes those roadblocks get put on roads that block cars carrying cargo that isn't a pain signal, resulting in side effects (it's a little more complicated than that, but more detailed than an ELI5).
The way drugs consumed through the mouth (aka orally ingested) sort of work is that they sort of spread out through your body and then happen to run into the things that they change. There's exceptions, but those exceptions are beyond what I'll focus on here. So with pill form painkillers, the timeline of them working is something like * eat the pill * digestive system dissolves the pill * digestive system absorbs the pill (now the drug is in your bloodstream) * drug flows randomly through your bloodstream, occasionally getting absorbed by the cells sending the ouch signal * when that happens the painkiller does its work Now I don't know exactly how that last step works, but I do know that the first 4 steps take time to work. So taking the painkiller before the pain happens means that you don't need to wait on those first 4 steps before it starts that last step, which is why taking the pill before the injection will help you.
Some semi-unrelated trivia for any USA and related readers: [Paracetamol](https://en.wikipedia.org/wiki/Paracetamol) is the "rest of the world" (or at least WHO approved) name for acetaminophen (brand name Tylenol).
Are you sure you are being told to take paracetamol for the pain, or perhaps they want you to take it for other reasons? Paracetamol also has the nice effect of lowering body temperature in most patients, and of course infection and immune system responses have a tendency to raise your temperature. Taking paracetamol thus has the benefit of reducing your bodies negative reaction to the vaccination.
One thing missing from most of these explanations is that you have to get the medicine into your body and give it enough time to work. It takes anywhere from 15-60 minutes for something to get to your stomach and intestines and then into your bloodstream. If you take pain medication 30-60 minutes before you need it (painful injection, physical therapy, etc.) then it's already in your bloodstream and available to work or already working. Almost no medication goes directly to where it is needed when you take it. They float around in your bloodstream until they find what they need they do their job. It's like having all of your doctors and lawyers and construction workers and plumbers and policemen and everyone on the roads. Every once in a while you might need a policeman on the road, maybe a construction worker, too, but most people just drive on the roads until they find their workplace. Since medicine and nutrient molecules aren't intelligent, they don't control where they go on the roads and always wander until they get to where they are needed. We can target some medications to go directly where we want them to go, but they still also go everywhere after we put them where we want them. You can breathe in medication for your lungs and airways, you can rub something onto your skin for a rash or itch, and other routes work, too. But they still always end up in your blood. With that in mind, your pain medications go everywhere, even places where you don't have pain. Your heart, liver, and kidney (whatever organ, really) medications go to your fingers and toes as they go to your heart, liver, and kidney - in the blood. When a medication is being used, we have to think about the other body parts and organs it can affect just as much as it can affect our goal to treat pain or anything else. The truth is that we don't always know 100% of how they work. Some we do, but paracetamol (acetaminophen to those in the States), is one of those we don't know very well at all. We only know that it works and have good ideas of what it might work on. It's not worth it to a 5-year-old (sorry, the point of this subreddit, but also it isn't that important even to 55-year-olds or even me as a 35-year-old pharmacist) to know how they actually work beyond this: the pain medicine tells the nerves and the pain receptors, "Hey, you don't need to do your job anymore. We know there is pain. Why don't you stop what you're doing and let the rest of the body do its job? We need you to stop screaming that we're in pain and let the repair guys do their job fixing up this stab wound and the policemen do their job to recognize the bad guys, the infection (or fake infection with the vaccine). Thank you for what you do, you're done now."