Ibuprofen is a non-selective inhibitor of an enzyme called cyclooxygenase (COX), which is required for the synthesis of prostaglandins via the arachidonic acid pathway. COX is needed to convert arachidonic acid to prostaglandin H2 (PGH2) in the body. This PGH2 is then converted to prostaglandins. The inhibition of COX by ibuprofen therefore lowers the level of prostaglandins made by the body.
The prostaglandins that are formed from PGH2 are important mediators of sensations such as pain and processes such as fever and inflammation. The antipyretic effects may arise as a result of action on the hypothalamus leading to vasodilation, an increased peripheral blood flow and subsequent heat dissipation.
Anticoagulant effects are also mediated through inhibition of COX, which converts arachidonic acid into thromboxane A2, a vital component in platelet aggregation that leads to the formation of blood clots.
There are two forms of COX in the body - COX-1 and COX-2. The pain and inflammation reducing effects of NSAIDs are mediated through the inhibition of COX-2, while COX-1 inhibition blocks the formation of thromboxane. The long-term blockage of COX-1 with chronic use of NSAID, however, may cause gastric toxicity, as COX-1 usually maintains the gastric mucosa.
Ibuprofen is used primarily to treat fever (including post-vaccination fever), mild to moderate pain (including pain relief after surgery), painful menstruation, osteoarthritis, dental pain, headaches, and pain from kidney stones. About 60% of people respond to any NSAID; those who do not respond well to a particular one may respond to another.
It is used for inflammatory diseases such as juvenile idiopathic arthritis and rheumatoid arthritis. It is also used for pericarditis and patent ductus arteriosus.
In some countries, ibuprofen lysine (the lysine salt of ibuprofen, sometimes called "ibuprofen lysinate") is licensed for treatment of the same conditions as ibuprofen; the lysine salt is used because it is more water-soluble. In 2006, ibuprofen lysine was approved in the US by the Food and Drug Administration (FDA) for closure of patent ductus arteriosus in premature infants weighing between 500 and 1,500 grams (1 and 3 lb), who are no more than 32 weeks gestational age when usual medical management (such as fluid restriction, diuretics, and respiratory support) is not effective.
Some people may suffer allergic reactions or asthma after taking ibuprofen, aspirin or other NSAIDs. Reaction symptoms may include:
If such reactions occur, do not take ibuprofen again.
Ibuprofen and other NSAIDs may cause bleeding, holes or ulcers in the stomach or intestines. The risk is higher for people who have taken NSAIDs for a long time, are elderly, in poor health, who smoke or drink regularly or have had a stomach ulcer in the past.
The NIH warns that ibuprofen may increase the risk of heart attack or stroke, especially in those who have already have heart disease.
There are some side effects associated with ibuprofen use. These are less serious side effects that NIH recommends talking to a doctor about if they persist:
The NIH recommends calling a doctor immediately in the case of the following side effects:
Dosage Forms & Strengths
OTC: 200-400 mg PO q4-6hr; not to exceed 1.2 g unless directed by physician
Prescription: 400-800 mg PO/IV q6hr
400-800 mg PO q6-8hr; not to exceed 3.2 g/day
300 mg, 400 mg, 600 mg, or 800 mg PO q6-8hr; not to exceed 3.2 g/day
Monitor for gastrointestinal (GI) risks
300 mg, 400 mg, 600 mg, or 800 mg PO q6-8hr; not to exceed 3200 mg/day
Monitor for GI risks
Significantly impaired renal function: Monitor closely; consider reduced dosage if warranted
Dosage Forms & Strengths
6 months to 12 years
4-10 mg/kg/dose PO q6-8hr; not to exceed 40 mg/kg/day
See ibuprofen IV drug monograph
<4 years: Safety and efficacy not established
≥4 years: PO administration q12hr, adjusted to maintain serum levels of 50-100 mcg/mL; may slow disease progression in younger patients with mild lung disease
Potential toxic dose in children <6 years: 200 mg/kg
Taking too much ibuprofen, known as an overdose, can be very dangerous.
If you've taken more than the recommended maximum dose, go to your nearest accident and emergency (A&E) department as soon as possible.
It can be helpful to take any remaining medicine and the box or leaflet with you to A&E if you can.
Some people feel sick, vomit, have abdominal pain or ringing in their ears (tinnitus) after taking too much ibuprofen, but often there are no symptoms at first. Go to A&E even if you're feeling well.
Drinking alcohol when taking ibuprofen may increase the risk of stomach bleeding.
According to the US Food and Drug Administration (FDA), "ibuprofen can interfere with the antiplatelet effect of low-dose aspirin, potentially rendering aspirin less effective when used for cardioprotection and strokeprevention." Allowing sufficient time between doses of ibuprofen and immediate-release (IR) aspirin can avoid this problem. The recommended elapsed time between a dose of ibuprofen and a dose of aspirin depends on which is taken first. It would be 30 minutes or more for ibuprofen taken after IR aspirin, and eight hours or more for ibuprofen taken before IR aspirin. However, this timing cannot be recommended for enteric-coated aspirin. But, if ibuprofen is taken only occasionally without the recommended timing, the reduction of the cardioprotection and stroke prevention of a daily aspirin regimen is minimal.
Ibuprofen can react unpredictably with certain other medicines. This can affect how well either medicine works and increase the risk of side effects.
Check the leaflet that comes with your medicine to see if it can be taken with ibuprofen. Ask your GP or local pharmacist if you're not sure.
As ibuprofen is a type of NSAID, you shouldn't take more than one of these at a time or you'll have an increased risk of side effects.
NSAIDs can also interact with many other medicines, including:
Read more about medicines that interact with NSAIDs.
Ibuprofen can also interact with ginkgo biloba, a controversial dietary supplement some people claim can treat memory problems and dementia.
There are no known problems caused by taking ibuprofen with any specific foods or by drinking a moderate amount of alcohol.
Carefully follow the dosing instructions provided with children's ibuprofen for the age and weight of your child. Ask a doctor or pharmacist if you have questions. Takeibuprofen with food or milk to lessen stomach upset. Shake the oral suspension (liquid) well just before you measure a dose.
Use caution in asthma (bronchial), cardiac disease, congestive heart failure (CHF), hepatic or renal impairment, hypertension. bleeding disorder, duodenal/gastric/peptic ulcer, stomatitis, systemic lupus erythematosus (SLE), ulcerative colitis, upper GI disease, late pregnancy (may cause premature closure of ductus arteriosus)
Long-term administration of NSAIDs may result in renal papillary necrosis and other renal injury; patients at greatest risk include elderly individuals; those with impaired renal function, hypovolemia, heart failure, liver dysfunction, or salt depletion; and those taking diuretics, angiotensin-converting enzyme (ACE) inhibitors, or angiotensin receptor blockers
Junior Advil (100 mg): Doses higher than recommended may cause stomach bleeding
May cause serious adverse reactions, including exfoliative dermatitis, toxic epidermal necrolysis, Steven's Johnson syndrome reported
Children's and Junior Advil (50 mg, 100 mg): May cause severe and persistent sore throat
Fever, rash, abdominal pain, nausea, liver dysfunction, and meningitis have occurred in patients with collagen-vascular disease, especially SLE
Blurred vision, scotomate, and changes in color vision reported; discontinue therapy if symptoms occur
Platelet aggregation and adhesion may be decreased; monitor patients with coagulation disorders receiving the therapy
Risk of hyperkalemia may increase in patients with diabetes, the elderly, renal disease, or with concomitant use of agents that can induce hyperkalemia including ACE inhibitors; monitor potassium closely
May cause drowsiness and dizziness; may impair physical or mental abilities to operate heavy machinery or driving
NSAIDS, except aspirin, increase risk of heart attack, heart failure, and stroke; which can be fatal; the risk is higher if patients use more than it was directed or for longer than needed
Use caution in patients with high blood pressure, heart disease, liver cirrhosis, kidney disease, asthma, thyroid disease, diabetes, glaucoma, have trouble urinating due to an enlarged prostate gland, or had a stroke
Patients should inform healthcare professional if they have symptoms of heart problems or stroke, chest pain, trouble breathing weakness in one part or side of body, slurred speech, leg swelling
Ideally, pregnant women shouldn't take ibuprofen unless a doctor recommends and prescribes it.
It's best to tell your GP, pharmacist or health visitor about any medicines you're taking.
Paracetamol is recommended as an alternative to ease short-term pain or reduce a high temperature.
Ibuprofen appears in breast milk in small amounts, so it's unlikely to cause any harm to your baby while you're breastfeeding.
Ibuprofen may be given to children aged three months or over who weigh at least 5kg (11lbs) to relieve pain, inflammation or fever.
Your GP or another healthcare professional may recommend ibuprofen for younger children in certain cases – for example, this may be to control a fever after a vaccination if paracetamol is unsuitable.