Last Updated on July 25, 2025 by Analgesia team
What is codeine, and how does it work?
Codeine is a mild opioid, chemically derived from opium but far less potent than morphine. It belongs to a group of medicines called opioid analgesics, which are used to treat pain.
Codeine ranks 5th on our list of the Top 10 Painkillers in the UK—and for good reason. It’s widely used, widely available, and when it works, it really works. But it also walks a fine line between relief and risk
So, how does codeine interact with the body?
It works by interfering with the way your brain and nervous system process pain signals. Instead of stopping the pain at its source, codeine dulls your perception of it. That’s why it’s used for mild to moderate pain, not severe trauma or surgery.
But pain relief isn’t its only trick.
Codeine also suppresses coughing. It acts on the cough reflex in your brain, making it useful in some prescription cough syrups — especially when a dry, hacking cough just won’t quit. However, this is not without risks, especially in children and the elderly.
In short, codeine doesn’t cure pain or illness. It changes how your body reacts to them — and that’s where both its power and its danger lie.
What is codeine used for?
Codeine is prized for its versatility. Primarily, it treats mild to moderate pain—but it pops up in several other scenarios, too.
– Post‑surgery discomfort: After a minor operation, codeine eases aches when paracetamol or ibuprofen alone aren’t enough.
– Dental pain: That throb after a wisdom‑tooth extraction? Codeine can dampen it.
– Period pain: When cramps leave you sidelined, a low‑dose codeine combo often does the trick.
– Back and muscle aches: Stiffness from strain or injury responds well to short‑term codeine use.
But that’s not all.
Codeine also features in cough medicines. By acting on your brain’s cough centre, it helps when a dry, hacking cough won’t quit—though it’s reserved for severe cases under prescription.
Codeine in combination products
Most UK pharmacies stock co‑codamol (paracetamol + codeine) and tylenol with codeine (the US equivalent). These combos let you use lower codeine doses while getting extra pain relief:
- Co‑codamol: Up to 8 mg codeine plus 500 mg paracetamol per tablet (OTC limit).
- Prescription‑strength options: Can go up to 30 mg codeine per dose—always under medical supervision.
Why combine? Two reasons:
- You get better pain control without upping the codeine risk.
- You use less codeine overall, cutting down side‑effect chances.
other uses
- Migraine relief (sparingly; risk of rebound headaches if overused)
- Cold symptoms when cough and aches overlap
- Adjunct therapy in palliative care, to improve quality of life for severe pain
How long does codeine take to work?
Codeine doesn’t kick in instantly—but when it does, you’ll feel the difference.
After swallowing a standard dose, codeine takes around 30 to 60 minutes to start working. The exact timing depends on how your body metabolises it. Once it kicks in, the peak effect usually comes around 1 to 2 hours later.
How long does it last?
You can expect pain relief or cough suppression to last 4 to 6 hours. That’s why codeine is typically taken every 4–6 hours, depending on the product and dosage.
But timing isn’t the same for everyone.
Some people feel codeine faster or stronger than others. That’s due to genetic differences in how your liver converts codeine into morphine—a process essential for its effect. If your body is a “fast metaboliser,” you might experience stronger effects or more side effects. If you’re a “slow metaboliser,” codeine might do almost nothing at all.
Pro tip: don’t chase the high
Because of this delay, some people wrongly assume it isn’t working and take an extra dose too soon. That’s how overdoses happen. Always wait at least 4 hours before taking another dose—unless your GP tells you otherwise.
In summary:
How long does codeine take to work? Around an hour.
How long does it last? Up to six hours.
How long should you wait before taking more? Four hours minimum.
What is the strongest amount of codeine available?
Codeine strength varies wildly—especially between what you can buy over the counter and what needs a prescription.
Let’s break it down.
Over-the-counter (OTC) limit in the UK
In the UK, the strongest codeine you can legally buy without a prescription contains:
- 8 mg of codeine
- Combined with 500 mg of paracetamol per tablet
- Sold as co-codamol (usually 8/500)
- Max dose: 2 tablets every 4–6 hours, up to 8 tablets in 24 hours
This low dose is designed to limit misuse while still offering pain relief for short-term conditions like dental pain, period cramps, or migraines.
Prescription-only strengths
If OTC doesn’t cut it, your GP might prescribe stronger options like:
- Co-codamol 15/500 or 30/500 (15 mg or 30 mg codeine with 500 mg paracetamol)
- Codeine phosphate tablets (15 mg, 30 mg, or even 60 mg as standalones)
- Compound ibuprofen-codeine or liquid forms for children (under strict medical guidance)
With prescriptions, you can be given up to 240 mg per day—but this comes with much higher risk of dependence, side effects, and overdose.
What about Tylenol with codeine?
That’s the North American version of co-codamol. In the US, Tylenol with Codeine comes in numbered strengths:
- #1: 7.5 mg codeine
- #2: 15 mg
- #3: 30 mg
- #4: 60 mg
While the brand differs, the content is similar to what UK doctors prescribe under the NHS.
A warning on “strongest” codeine
Just because it’s stronger doesn’t mean it’s better. Higher doses of codeine increase your chances of:
- Constipation
- Drowsiness
- Breathing problems
- Addiction and withdrawal
So if you’re asking, “What is the strongest amount of codeine?” — the answer is up to 60 mg per dose under medical supervision. But unless your pain truly requires it, going stronger can quickly turn from treatment to trouble.
Who should not take codeine?
Codeine isn’t safe for everyone. In fact, for some people, even a small dose can cause serious harm—or even be fatal.
Here’s who should stay away from it (unless told otherwise by a doctor):
🚫 Children under 12
Codeine is strictly not recommended for children under 12. Their bodies can’t process it safely, and the risk of breathing difficulties or overdose is dangerously high.
🚫 Teenagers after tonsil or adenoid surgery
Even kids aged 12–18 should avoid codeine after surgery for sleep apnoea, such as tonsil or adenoid removal. The MHRA warns it can cause severe breathing problems, especially in rapid metabolisers.
🚫 People with breathing issues
If you have asthma, COPD, or other lung problems, codeine can slow your breathing further and make symptoms worse. In some cases, it can lead to respiratory failure.
🚫 Pregnant or breastfeeding women
Codeine crosses the placenta and passes into breast milk, where it can cause breathing issues in newborns—especially if the mother is a fast metaboliser. It’s generally avoided during pregnancy unless the benefits outweigh the risks.
🚫 Liver or kidney problems
These organs break down and clear codeine. If they’re impaired, codeine can build up to toxic levels even at standard doses.
🚫 Epilepsy and head injuries
Codeine can increase the risk of seizures and raised intracranial pressure, making it unsafe for people with epilepsy or brain trauma.
🚫 Mixing with other depressants
Never take codeine with:
- Alcohol
- Sleeping tablets
- Benzodiazepines (e.g. diazepam, lorazepam)
- Other opioids
These combinations slow your breathing and heartbeat, and can be fatal—even if each is taken at a “normal” dose.
So—who should not take codeine?
If you fall into any of these categories, codeine could do more harm than good. Always speak to your GP or pharmacist before using it—especially if you’re on other medication or managing a long-term condition.
Can codeine get you high?
Yes—codeine can get you high. And that’s part of the problem.
At higher doses, codeine doesn’t just block pain—it also triggers a dopamine rush in the brain, creating a sense of euphoria, warmth, or detachment. Some people describe it as feeling “floaty” or numb.
That’s why codeine, despite being milder than morphine or oxycodone, is still classified as a controlled drug in the UK when sold in higher doses.
What does a codeine high feel like?
- Relaxation or drowsiness
- Light-headedness
- Emotional detachment
- Slurred speech
- Slowed reaction times
But there’s a catch: those effects don’t last long, and your body builds tolerance fast. This leads some people to take more, sooner, chasing that same feeling.
That’s how misuse begins.
The dangers of chasing a codeine high
- Respiratory depression – Your breathing can slow to a dangerous level, especially if mixed with alcohol or other depressants.
- Addiction – Codeine may seem harmless at first, but psychological and physical dependency can form quickly.
- Accidental overdose – Particularly when combined with paracetamol (as in co-codamol), taking too much risks liver failure.
- Withdrawal symptoms – Stop suddenly after regular use and you may face sweating, nausea, chills, muscle aches, and agitation.
Recreational use in the UK
Illicit use of codeine is growing—especially among teens and young adults. Some mix codeine with soda and sweets to make “lean” or “purple drank,” glamorised in music and social media. But behind the trend is a trail of hospitalisations and deaths.
Important: Getting high on codeine isn’t a side effect. It’s a sign of misuse. And it can quickly spiral into addiction.
What are the side effects of codeine?
Codeine doesn’t just dull pain—it slows your whole system down. That’s how it works. But it also explains why side effects are so common.
Let’s start with the ones most people notice:
🟠 Common side effects of Codeine
- Drowsiness or sleepiness
- Constipation
- Nausea or vomiting
- Dry mouth
- Dizziness or light-headedness
- Slower reaction times
These effects are usually mild if you’re taking codeine at the correct dose for a short time. But even then, they can interfere with your ability to drive, work, or stay alert.
🔴 Serious side effects (seek help immediately)
- Shallow or slow breathing
- Confusion or hallucinations
- Extreme drowsiness or unresponsiveness
- Seizures
- Severe allergic reactions (rash, swelling, itching, difficulty breathing)
- Liver damage (especially with combination drugs like co-codamol if taken in excess)
🚨 Codeine + alcohol = a dangerous mix
Alcohol and codeine both depress the central nervous system. Taken together, they dramatically increase the risk of:
- Respiratory failure
- Coma
- Death
Even a single glass of wine can be too much when you’re on codeine. Bottom line: don’t mix the two—ever.
How to reduce side effects
- Stick to the lowest effective dose
- Avoid driving or operating machinery
- Stay hydrated and increase fibre to manage constipation
- Take with food if nausea strikes
- Avoid alcohol and other sedatives
If the side effects don’t ease after a few days—or if they get worse—speak to a pharmacist or GP. You may need a different medication or a lower dose.
Codeine addiction: a growing concern in the UK
Codeine addiction doesn’t always start with misuse. For many, it begins with a standard dose taken for real pain. But over time, what once worked doesn’t anymore—so you take more. And that’s where things unravel.
How does codeine addiction happen?
Codeine is converted into morphine in the liver. This triggers a release of dopamine, the brain’s feel-good chemical. The more you use it, the more your brain expects that reward.
With repeated use, your body:
- Builds tolerance – You need more codeine for the same effect
- Becomes dependent – You feel unwell if you stop
- Forms habits – You begin to crave it, even when pain is gone
This is the cycle of addiction—and it can develop in just a few weeks.
Signs you might be addicted to codeine
- Taking codeine more often or at higher doses than prescribed
- Needing it to feel normal, not just for pain
- Visiting multiple pharmacies (known as “pharmacy hopping”)
- Hiding usage from friends or family
- Feeling anxious, irritable, or unwell when you miss a dose
- Constantly thinking about when you’ll take your next tablet
NHS and UK codeine addiction statistics
Addiction isn’t rare—and it’s not just happening behind closed doors.
- In 2023, there were over 14,000 hospital admissions in England linked to opioid poisoning, including codeine.
- Codeine is now one of the most misused prescription painkillers in the UK, especially among young adults.
- A 2022 Public Health England report showed that 1 in 10 regular codeine users showed signs of dependency.
- Calls to addiction helplines about codeine doubled between 2017 and 2022.
These are not fringe cases. This is a public health issue.
What to do if you think you’re addicted
You’re not stuck. Help is available—and the earlier, the better.
Reach out to:
- Your GP – They can support you with tapering plans or refer you to addiction services
- NHS drug treatment services – Free and confidential
- Talk to Frank – 0300 123 6600
- We Are With You – Offers one-to-one support across the UK
- Release – Legal and drug advice for those concerned about opioid use
Final word
Addiction to codeine can happen quietly. You don’t need to be abusing it to be at risk. If you find yourself needing it more often or in higher doses, it’s time to pause and ask: Why?
Can you take codeine with paracetamol or ibuprofen?
Yes, and in fact, that’s how most people take it. Codeine is rarely used on its own. It’s almost always combined with another painkiller to make it more effective—and to reduce how much codeine you need.
💊 Codeine and paracetamol: co-codamol
This is the most common combo.
- Co-codamol combines codeine (usually 8 mg, 15 mg, or 30 mg) with 500 mg of paracetamol.
- Available over the counter in lower strengths (8/500), and prescription-only in stronger doses (15/500 and 30/500).
- The paracetamol boosts the pain-relieving effect without increasing opioid risk too much—if taken properly.
💊 Codeine and ibuprofen
Another option, available by prescription or at lower doses from pharmacies.
- Brands like Nurofen Plus contain 200 mg of ibuprofen and 12.8 mg of codeine.
- Good for inflammatory pain, like back pain or arthritis, where the ibuprofen targets swelling and codeine adds pain control.
❌ Codeine and alcohol: never mix
Although you can safely combine codeine with paracetamol or ibuprofen, you should never take it with alcohol.
Why?
Because both alcohol and codeine depress your central nervous system. Taken together, they can:
- Slow or stop your breathing
- Knock you out cold
- Increase your risk of overdose—even at normal doses
Even a small amount of alcohol can tip the balance when codeine is in your system.
So yes…
You can take codeine with paracetamol or ibuprofen. That’s standard practice. But mixing it with alcohol? That’s dangerous, full stop.
How to use codeine safely
Codeine is effective—but only if you respect its limits. Used carelessly, it can cause more problems than it solves. So here’s how to stay safe while getting the relief you need.
✅ Stick to the lowest effective dose
Don’t chase stronger effects. For short-term pain, 8–30 mg every 4 to 6 hours is usually enough. Never exceed the recommended dose on the label or from your doctor.
More isn’t better—it’s just riskier.
✅ Limit how long you use it
Three days max is the general rule for over-the-counter codeine (like co-codamol). If you need it longer, speak to your GP. Longer use increases your chances of side effects, tolerance, and addiction.
✅ Take it with food or a full glass of water
This helps reduce nausea and protects your stomach—especially when combined with ibuprofen.
Don’t drive or operate heavy machinery
Codeine can make you drowsy, dizzy, or slow your reflexes—even if you don’t feel “high.” Until you know how it affects you, play it safe. And if you feel off? Don’t drive.
Never combine it with alcohol, sleeping pills, or sedatives
We’ve said it before, but it’s worth repeating: codeine plus alcohol or other depressants can stop your breathing. The same goes for drugs like diazepam, tramadol, or antihistamines that make you sleepy.
Be honest with your GP or pharmacist
Let them know if you’re already taking:
- Other painkillers (paracetamol, ibuprofen, aspirin)
- Cough syrups or cold meds
- Antidepressants or anti-anxiety drugs
- Sleeping tablets or muscle relaxants
- Any herbal supplements
This helps avoid dangerous interactions or accidental overdose.
Watch for signs of dependency
If you start needing codeine to feel “normal,” or if you’re taking it when you’re not really in pain, pause. That’s often the first sign of a problem.
Safe doesn’t mean harmless. Codeine is a useful tool when used right—but you need to know where the line is.
The bottom line: Should you take codeine?
If your pain is mild to moderate—and paracetamol or ibuprofen isn’t cutting it—codeine might help. But it’s not a casual painkiller. It’s not one you pop just because your head hurts a bit. It’s an opioid. And that comes with baggage.
✔️ When codeine makes sense
- Short-term, moderate pain (like after surgery or injury)
- Dry, tickly cough that keeps you up at night
- Menstrual pain that doesn’t respond to NSAIDs
- As a step-up from regular painkillers, under medical advice
⚠️ When you should avoid it
- If you have asthma, COPD, or breathing problems
- If you’re pregnant or breastfeeding (unless told otherwise by your doctor)
- If you’re already taking other sedatives or antidepressants
- If you have a history of addiction, even to alcohol or nicotine
- If you’re under 18 years old, especially after surgery
Remember: codeine affects your brain
It changes how you process pain—but it also alters mood, slows breathing, and can hook you fast. The risk of dependency rises the longer you use it—even if you’re taking it “properly.”
Use it as a last resort, not a first option
If paracetamol or ibuprofen works, stick with that. If codeine is needed, use the lowest dose, for the shortest time, and always with medical guidance.
Because once you cross the line into daily use, it’s a different game.