How do ibuprofen and paracetamol differ?
Ibuprofen is an NSAID pain reliever that relieves pain, reduces inflammation and lowers fever. Paracetamol relieves pain and lowers fever but has no anti-inflammatory effect.
- 💊 Ibuprofen — pain relief + anti-inflammatory + fever reducer
- 💊 Paracetamol — pain relief + fever reducer (no anti-inflammatory effect)
- ✅ Pain with inflammation → choose ibuprofen
- ✅ Ordinary pain / stomach problems → choose paracetamol
- ✅ Safe to combine — alternate the two when one alone does not control the pain or fever
- ⏱️ Ibuprofen can be repeated every 6-8 hours; paracetamol can be repeated more often, every 4-6 hours
Why compare ibuprofen and paracetamol?
Ibuprofen vs paracetamol is one of the most common pharmacy questions in Thailand. Both are the two pain relievers Thai people know best, and both are easy to find at any pharmacy. Still, many people are unsure which one suits which kind of pain, or whether the two can be taken together.
Both are pain relievers, but they work through different mechanisms and suit different situations. Choosing the right one helps pain resolve faster and avoids unnecessary side effects.
How do their mechanisms differ?
Ibuprofen — blocks COX enzymes to reduce inflammatory substances
Ibuprofen belongs to the NSAID (Non-Steroidal Anti-Inflammatory Drug) class. It works by inhibiting the COX-1 and COX-2 enzymes, which the body uses to produce prostaglandins — the substances behind pain, swelling, inflammation and fever.
When less prostaglandin is produced → pain, inflammation and fever all decrease.
Paracetamol — acts directly in the brain
Paracetamol (acetaminophen) acts on the central nervous system, reducing prostaglandin production in the brain. This lowers the sensation of pain and reduces fever, but it does not reduce inflammation at its source.
In simple terms, paracetamol "tells the brain not to feel pain" without treating the site of inflammation itself.
| Ibuprofen | Paracetamol | |
|---|---|---|
| Drug class | NSAID | Analgesic/antipyretic (not an NSAID) |
| Site of action | Blocks COX-1/COX-2 throughout the body | Acts in the brain |
| Relieves pain | ✅ | ✅ |
| Reduces inflammation | ✅ | ❌ |
| Reduces fever | ✅ | ✅ |
Comparing effects — which is better for what?
Conditions where ibuprofen works better
Because it also reduces inflammation, ibuprofen suits conditions where inflammation is also present:
- Period pain — the uterus contracts because of prostaglandins, and ibuprofen directly lowers this substance, so it relieves period pain more effectively.
- Toothache / tooth extraction — usually comes with swelling and inflammation.
- Muscle pain / sprains — involves inflammation of the tissue.
- Joint pain / arthritis — ibuprofen reduces both pain and swelling.
- Migraine — several studies have found ibuprofen relieves migraine well.
👉 Want more detail on what ibuprofen treats? Read more at [What can ibuprofen 400 mg treat? Uses many people don't know]
Conditions where paracetamol works better (or is more suitable)
Paracetamol is not "better at relieving pain" in every case, but it is more suitable in certain situations:
- Ordinary headaches (not migraine) — a headache from stress or lack of sleep has no inflammation, so paracetamol is enough.
- Reducing fever in young children — paracetamol is safer for children.
- People with stomach problems — paracetamol does not irritate the stomach.
- Pregnant women — paracetamol is the pain reliever recommended for pregnant women (ibuprofen must not be used in the third trimester).
- People taking blood thinners — ibuprofen increases bleeding risk, so paracetamol is safer.
Comparing side effects
| Side effect | Ibuprofen | Paracetamol |
|---|---|---|
| Stomach irritation | ⚠️ Higher risk | ✅ Rare |
| Stomach ulcers | ⚠️ Risk with prolonged use | ✅ Not a risk |
| Liver toxicity | ✅ Low risk | ⚠️ High risk if overdosed |
| Effect on kidneys | ⚠️ Risk with prolonged use | ✅ Low risk |
| Bleeding tendency | ⚠️ Affects platelets | ✅ No effect |
| Use in pregnancy | ❌ Avoid in third trimester | ✅ Can be used |
| Use in young children | ⚠️ Caution (from 6 months) | ✅ Usable from birth |
⚠️ Want more detail on ibuprofen's side effects? 👉 [Who should not take ibuprofen? Side effects and precautions]
Comparing onset and duration
| Ibuprofen | Paracetamol | |
|---|---|---|
| Onset | 20-30 minutes | 15-30 minutes |
| Peak effect | 1-2 hours | 1-1.5 hours |
| Duration of effect | 4-6 hours | 4-6 hours |
| Repeat dose interval | Every 6-8 hours | Every 4-6 hours |
Both drugs start working at a similar speed, but paracetamol can be repeated more often (every 4-6 hours) because it does not irritate the stomach.
👉 Read more about how long ibuprofen's effects last at [How many hours does ibuprofen 400 mg last? When can I take it again?]
Which pain, which drug?
Here's a quick cheat sheet for choosing the right pain reliever for the symptom:
| Symptom | Recommended | Why |
|---|---|---|
| Ordinary headache | Paracetamol | No inflammation, so an NSAID is not needed |
| Migraine | Ibuprofen | Studies support good results |
| Period pain | Ibuprofen | Lowers the prostaglandin that makes the uterus contract |
| Toothache / tooth extraction | Ibuprofen | Comes with swelling and inflammation |
| Muscle pain / sprains | Ibuprofen | Reduces inflammation at the source |
| Joint pain / arthritis | Ibuprofen | Reduces both pain and swelling |
| General fever | Either drug | Both reduce fever about equally well |
| Fever in young children | Paracetamol | Safer for children |
| People with stomach problems | Paracetamol | Does not irritate the stomach |
| Pregnant women | Paracetamol | Ibuprofen must be avoided in the third trimester |
| People taking blood thinners | Paracetamol | Ibuprofen increases bleeding risk |
Can I take ibuprofen and paracetamol together?
Yes — they belong to different drug classes and work through different mechanisms, so they do not interact with each other.
A suggested alternating schedule
For severe pain or high fever that one drug alone cannot control, you can alternate the two, for example:
- Hour 0 — take ibuprofen
- Hour 3 — take paracetamol
- Hour 6 — take ibuprofen (6 hours after the first dose)
- Hour 9 — take paracetamol
This keeps one of the two drugs active throughout the day without exceeding the maximum dose of either one.
⚠️ Alternating the two should only be done when truly necessary, and not for several days in a row without asking a doctor or pharmacist.
👉 Read more about taking ibuprofen correctly at [How to take ibuprofen 400 mg correctly and safely]
Ibuprofen vs paracetamol — summary
| Ibuprofen | Paracetamol | |
|---|---|---|
| Strength | Relieves pain + reduces inflammation | Gentler on the stomach, generally safer |
| Weakness | Can irritate the stomach | Does not reduce inflammation; toxic to the liver if overdosed |
| Best for | Pain that comes with inflammation | Ordinary pain, fever, people with stomach problems |
Neither pain reliever is better than the other in every situation. What matters is matching the drug to the symptom and using the right dose. Ask a pharmacist first if you are unsure.
Frequently Asked Questions
Neither is "stronger" in every case — the two drugs work through different mechanisms. Ibuprofen also reduces inflammation, so it relieves pain that involves inflammation, such as period pain or joint pain, more effectively than paracetamol in those situations. Paracetamol suits ordinary pain without inflammation and is gentler on the stomach. The right choice depends on the type of pain, not on one drug always being stronger. Ask a pharmacist if you are unsure.
It is not recommended — take ibuprofen with food or right after a meal. Ibuprofen can irritate the stomach lining, and having food in the stomach lowers that risk. Paracetamol, by contrast, can be taken on an empty stomach because it does not irritate it. If you have a history of stomach ulcers, ask a pharmacist before taking ibuprofen.
Yes, from six months of age, dosed by body weight — but paracetamol is usually the first choice for reducing fever in young children because it has a longer safety record and can be used from birth. If the fever does not come down or the child seems unwell, ask a pharmacist or doctor before giving any medicine to a child.
Both ibuprofen and paracetamol are considered compatible with breastfeeding, since only a very small amount passes into breast milk. Doctors and pharmacists generally recommend choosing based on the type of pain, the same as for anyone else — paracetamol for ordinary pain, ibuprofen when inflammation is also present. Always ask a pharmacist before taking any medicine continuously while breastfeeding.
As a general rule, do not self-treat pain or fever with ibuprofen for more than three days in a row. If symptoms have not improved, ask a pharmacist or doctor — prolonged use of ibuprofen raises the risk to the stomach and kidneys. Paracetamol also has a daily maximum dose. Neither drug should be used continuously without professional advice.
Very dangerous. Paracetamol overdose is a leading cause of acute drug-induced liver failure, because the liver must metabolise paracetamol, and at overdose levels the resulting byproduct damages liver cells. Symptoms may not appear until significant liver damage has already occurred. If you suspect an overdose, go to a hospital immediately — do not wait for symptoms to appear.
Paracetamol is generally the safer choice for people with kidney problems, because ibuprofen is an NSAID that reduces blood flow to the kidneys and can worsen kidney function, especially in those who already have chronic kidney disease. Paracetamol still needs to be used at an appropriate dose, though. Anyone with kidney disease should ask a doctor or pharmacist before taking either pain reliever.
No — never double up to make up for a missed dose. For both ibuprofen and paracetamol, simply take the next dose at its normal amount and normal time. Doubling up increases the risk of side effects, particularly for paracetamol, where exceeding the total daily dose puts the liver at risk. Ask a pharmacist if you are unsure about the right dose for you.
⚠️ Disclaimer
The information on this page is for general informational purposes only and is not intended to replace professional medical advice, diagnosis, or treatment from a qualified doctor or pharmacist. If you have any questions about your symptoms or medication, always consult a doctor or pharmacist first.
References
- Ibuprofen vs Acetaminophen: Differences and Similarities — Drugs.com
- Appropriateness and Abuse of Antipyretics, Anti-Inflammatory Drugs and Antibiotics in Children and Adults — The Cochrane Database of Systematic Reviews
- Non-prescription (OTC) Oral Analgesics for Acute Pain — StatPearls, National Library of Medicine
- Over-the-counter non-steroidal anti-inflammatory medications: Focus on the management of acute pain — Cochrane Review
- NSAIDs vs Paracetamol for Dysmenorrhea — Cochrane Library
- Over-the-Counter Pain Relievers — U.S. FDA
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