Ibuprofen – Side Effects


Ibuprofen is a non-steroidal anti-inflammatory drug (NSAID) derived from propionic acid and it is considered the first of the propionics. The formula of ibuprofen is 2-(4-isobutylphenyl) propionic acid and its initial development was in 1960 while researching for a safer alternative for aspirin. Ibuprofen was finally patented in 1961 and this drug was first launched against rheumatoid arthritis in the UK in 1969 and USA in 1974. It was the first available over-the-counter NSAID.

On the available products, ibuprofen is administered as a racemic mixture. Once administered, the R-enantiomer undergoes extensive interconversion to the S-enantiomer in vivo by the activity of the alpha-methylacyl-CoA racemase. In particular, it is generally proposed that the S-enantiomer is capable of eliciting stronger pharmacological activity than the R-enantiomer.



Properties and Characteristics of Ibuprofen

Drug class Nonsteroidal anti-inflammatory drug
Brand Names Addaprin, Advil, Advil Cold and Sinus, Advil Congestion Relief, Advil PM, Advil Sinus Congestion and Pain, Alivio, Caldolor, Cedaprin, Children’s Ibuprofen, Diphen, Duexis, Ibu, Ibutab, Junior Strength Motrin, Motrin, Motrin PM, Neoprofen, Nuprin, Pedea, Proprinal, Reprexain, Sudafed PE Head Congestion Plus Pain, Vicoprofen, Wal-profen Congestion Relief and Pain
Synonyms Ibuprofen, Ibuprofene, Ibuprofeno, Ibuprofenum


Molecular Formula C13H18O2
Molecular Weight 206.28 g/mol
IUPAC Names 2-[4-(2-methylpropyl)phenyl]propanoic acid
Structural formula of main components         Ibuprofen structure.png
Pure active ingredient  Ibuprofen
Appearance Colorless, crystalline stable solid
Melting point 75-77.5 ºC
Solubility        21mg/L (at 25 °C)
Excretion Excreted in urine
Available forms Tablets, capsules, liquids, gels or creams, sprays
Storage Should be stored in well closed, light resistant containers at 15-30 °C
Prescription Prescription is required


People can take ibuprofen by mouth as a syrup or tablet. They can also apply it directly to the skin as a mousse, gel, or spray.

  • Fever
  • Inflammation
  • Headache
  • Menstrual pain
  • The common cold
  • Toothache
  • Back pain
  • Arthritis
  • Sprains

Some medications, such as decongestants, have ibuprofen added to create, for example, a combined cold or flu remedy.

Other products combine ibuprofen with opioids, such as oxycodone. These are for short-term use only, as they can result in misuse.

Ibuprofen side effects

Get emergency medical help if you have signs of an allergic reaction to ibuprofen (hives, difficult breathing, swelling in your face or throat) or a severe skin reaction (fever, sore throat, burning eyes, skin pain, red or purple skin rash with blistering and peeling).

Get emergency medical help if you have signs of a heart attack or stroke: chest pain spreading to your jaw or shoulder, sudden numbness or weakness on one side of the body, slurred speech, leg swelling, feeling short of breath.

Stop using this medicine and call your doctor at once if you have:

  • Changes in your vision;
  • Shortness of breath (even with mild exertion);
  • Swelling or rapid weight gain;
  • A skin rash, no matter how mild;
  • Signs of stomach bleeding – bloody or tarry stools, coughing up blood or vomit that looks like coffee grounds;
  • Liver problems – nausea, upper stomach pain, itching, tired feeling, flu-like symptoms, loss of appetite, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes);
  • Low red blood cells (anemia) – pale skin, feeling light-headed or short of breath, rapid heart rate, trouble concentrating; or
  • Kidney problems – little or no urinating, painful or difficult urination, swelling in your feet or ankles, feeling tired or short of breath.

Common ibuprofen side effects may include:

  • Nausea, vomiting, gas;
  • Bleeding; or
  • Dizziness, headache.

This is not a complete list of side effects and others may occur.

Mechanism of action

The exact mechanism of action of ibuprofen is unknown. However, ibuprofen is considered an NSAID and thus it is a non-selective inhibitor of cyclooxygenase, which is an enzyme involved in prostaglandin (mediators of pain and fever) and thromboxane (stimulators of blood clotting) synthesis via the arachidonic acid pathway.

Ibuprofen is a non-selective COX inhibitor and hence, it inhibits the activity of both COX-1 and COX-2. The inhibition of COX-2 activity decreases the synthesis of prostaglandins involved in mediating inflammation, pain, fever, and swelling while the inhibition of COX-1 is thought to cause some of the side effects of ibuprofen including GI ulceration.

Drug Interactions

Sometimes, one medication can interfere with the effects of another. Specialists refer to this as drug interaction.

Drugs that may interact with ibuprofen:

  • Lithium
  • Warfarin
  • Oral hypoglycemics
  • High dose methotrexate
  • Medication for lowering blood pressure
  • Angiotensin-converting enzyme inhibitors
  • Beta-blockers
  • Diuretics

This may not be an exhaustive list of drugs that interact with ibuprofen. Anyone who is considering using ibuprofen should ask a pharmacist or doctor whether it is safe to do so with their existing medication.


The dose of this medicine will be different for different patients. Follow your doctor’s orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

  • For oral dosage form (tablets and suspension):
    • For fever:
      • Children over 2 years of age—Use and dose must be determined by your doctor.
      • Children 6 months of age up to 2 years—Dose is based on body weight and body temperature, and must be determined by your doctor. For fever lower than 102.5 °F (39.2 °C), the dose usually is 5 milligrams (mg) per kilogram (kg) (about 2.2 mg per pound) of body weight. For higher fever, the dose usually is 10 mg per kg (about 4.5 mg per pound) of body weight. The medicine may be given every six to eight hours, as needed, up to 40 mg per kg per day.
      • Infants younger than 6 months of age—Use and dose must be determined by your doctor.
    • For menstrual cramps:
      • Adults—400 milligrams (mg) every four hours, as needed.
      • Children—Use and dose must be determined by your doctor.
    • For mild to moderate pain:
      • Adults and teenagers—400 milligrams (mg) every four to six hours, as needed.
      • Children over 6 months of age—Dose is based on body weight and must be determined by your doctor. The dose usually is 10 milligrams (mg) per kilogram (kg) of body weight every six to eight hours, as needed, up to 40 mg per kg per day.
      • Infants younger than 6 months of age—Use and dose must be determined by your doctor.
    • For osteoarthritis and rheumatoid arthritis:
      • Adults and teenagers—1200 milligrams (mg) up to 3200 mg per day divided into three or four equal doses.
      • Children—Dose is based on body weight and must be determined by your doctor. The dose usually is 30 milligrams (mg) to 40 mg per kilogram (kg) of body weight per day, divided into three or four doses.
      • Infants younger than 6 months of age—Use and dose must be determined by your doctor

High doses

Taking high doses of ibuprofen over long periods of time can increase your risk of:

  • Stroke – when the blood supply to the brain is disturbed
  • Heart attacks – when the blood supply to the heart is blocked

In women, long-term use of ibuprofen might be associated with reduced fertility. This is usually reversible when you stop taking ibuprofen.

Overdoses of ibuprofen

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.

What special precautions should I follow?

Before taking ibuprofen,

  • Tell your doctor and pharmacist if you are allergic to ibuprofen, aspirin or other NSAIDs such as ketoprofen and naproxen (Aleve, Naprosyn), any other medications, or any of the inactive ingredients in the type of ibuprofen you plan to take. Ask your pharmacist or check the label on the package for a list of the inactive ingredients.
  • Tell your doctor and pharmacist what prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Your doctor may need to change the doses of your medications or monitor you more carefully for side effects.
  • Do not take nonprescription ibuprofen with any other medication for pain unless your doctor tells you that you should.
  • Tell your doctor if you have or have ever had asthma, especially if you also have frequent stuffed or runny nose or nasal polyps (swelling of the inside of the nose); heart failure; swelling of the hands, arms, feet, ankles, or lower legs; lupus (a condition in which the body attacks many of its own tissues and organs, often including the skin, joints, blood, and kidneys); or liver or kidney disease. If you are giving ibuprofen to a child, tell the child’s doctor if the child has not been drinking fluids or has lost a large amount of fluid from repeated vomiting or diarrhea.
  • If you are having surgery, including dental surgery, tell the doctor or dentist that you are taking ibuprofen.
  • Talk to your doctor about the risks and benefits of taking ibuprofen if you are 75 years of age or older. Do not take this medication for a longer period of time or at a higher dose than recommended on the product label or by your doctor.
  • If you have phenylketonuria (PKU, an inherited condition in which a special diet must be followed to prevent damage to your brain that can cause severe intellectual disability), read the package label carefully before taking nonprescription ibuprofen. Some types of nonprescription ibuprofen may be sweetened with aspartame, a source of phenylalanine.

Pregnancy, breastfeeding and fertility while taking or using ibuprofen

Ibuprofen and pregnancy

Ibuprofen is not usually recommended in pregnancy, unless it’s prescribed by a doctor, especially if you’re more than 30 weeks pregnant. This is because ibuprofen can affect your baby’s circulation and kidneys. There may also be a link between taking ibuprofen in early pregnancy and miscarriage.

Always talk to a doctor or pharmacist before taking ibuprofen if you’re pregnant. Your doctor can advise you about the benefits and possible harms of taking it.

A short course of ibuprofen may be OK, but it will depend on how many weeks pregnant you are and the reason you need to take the medicine. There may be other treatments that are more suitable for you.

Paracetamol is the best painkiller to take during pregnancy.

Ibuprofen and breastfeeding

You can take ibuprofen or use it on your skin while breastfeeding. It is one of the painkillers that’s usually recommended if you’re breastfeeding.

Only tiny amounts get into breast milk and it’s unlikely to cause side effects in your baby. Many people have used it while breastfeeding without any problems.

If you notice that your baby is not feeding as well as usual, or if you have any other concerns about your baby, talk to your midwife, health visitor, pharmacist or doctor as soon as possible.

Ibuprofen and fertility

Taking ibuprofen occasionally for pain relief, for example when you have a headache, is unlikely to affect your fertility. However, it’s best not to take ibuprofen tablets, capsules, granules or liquid for a long time (more than a week) if you’re trying to get pregnant. In this case paracetamol is a better option.

This is because taking ibuprofen (tablets, capsules, granules or liquid) in large doses, or for a long time, can affect ovulation. This can make it more difficult for you to get pregnant, but you will usually start ovulating normally again when you stop taking ibuprofen.

There’s no clear evidence to suggest that taking ibuprofen will reduce fertility in men.

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