Acetaminophen vs Ibuprofen

What Are The Differences Between Acetaminophen And Ibuprofen?


Acetaminophen and ibuprofen are over-the-counter medications for pain relief and fever reduction.

The differences between both drugs help us to make decisions about their use and maximize effectiveness. It also helps avoid potential side effects and drug interactions and ensures their safe use.

This article will explore and compare both drugs’ mechanisms of action, uses, interactions, and safety profiles.

How Acetaminophen And Ibuprofen Work?

Acetaminophen vs Ibuprofen

How Acetaminophen And Ibuprofen Work?

Acetaminophen (also known as paracetamol) is an analgesic (pain reliever) and antipyretic (fever reducer), belonging to the class of drugs known as non-opioid analgesics (1). Acetaminophen inhibits the production of prostaglandins, which are chemicals found inside the body that cause fever and pain sensations.

Acetaminophen gained popularity after its discovery for its role in easing pain and reducing fever. It was introduced as a medication in the 1950s and is the most used over-the-counter medication worldwide (2).

Ibuprofen belongs to the class of nonsteroidal anti-inflammatory drugs (NSAID) (3). It inhibits the ability of your body to produce prostaglandins by blocking the activity of enzymes called cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2). These enzymes are necessary to produce prostaglandins, which, in turn, cause pain, fever, and inflammation. As a result of decreased production of prostaglandins, pain, fever, and inflammation can be reduced.

Ibuprofen was made available for medical use in the 1970s. First, it was a prescription-only drug, but later, it became available as an over-the-counter (OTC) medication. It is a popular choice for different medical conditions. (4)

Common Medical Conditions They Are Used For


  • Mild to moderate pain (headaches, toothaches, muscle aches, and menstrual cramps).
  • Fever due to the common cold or the flu.
  • Post-surgical pain.
  • Osteoarthritis or rheumatoid arthritis.
  • Back pain. (5)

Acetaminophen does not possess any significant anti-inflammatory effects similar to ibuprofen.


  • Migraine headaches, dental pain, menstrual cramps, muscle aches, and joint pain.
  • Arthritis, osteoarthritis, and rheumatoid arthritis.
  • Fever.
  • Sports-related injuries, such as sprains. (3)

Choosing the medication involves considering underlying conditions, symptoms, and individual needs. Personalized advice from a qualified medical expert can help you understand what effective treatment options are.

Recommended Dose


The recommended dose in adults is 325-650 mg. It can be taken three to four times daily; the maximum daily dose is 4,000 mg, although it is recommended not to exceed 3000 mg daily (6).

Follow the instructions on the product or healthcare professional for appropriate dosing.


The recommended adult dose ranges between 200-400 mg. It can be taken every 4-6 hours as needed. The maximum daily dose of Ibuprofen in adults is 1,200-2,400 mg (7).

Side Effects


It is generally safe and well-tolerated. However, taking it for a long term and exceeding the maximum daily dose can lead to liver damage.

The common acetaminophen side effects are (5):

Allergic reactions including rash, red, peeling, blistering skin, hives, itching, and difficulty breathing. They can range from mild to life-threatening allergic reactions.
Stomach pain, loss of appetite,  tiredness, dark urine, and clay-colored stools can be signs of liver dysfunction due to acetaminophen overdose.


Common side effects of ibuprofen are (8)

  • Stomach upset, heartburn, indigestion, nausea, and diarrhea.
  • Less common side effects include (8):
  • Stomach ulcers.
  • Gastrointestinal bleeding.
  • Allergic reactions (rash, itching, swelling).
  • Fluid retention.
  • Increased risk of stroke or heart attack.

Which Is More Efficacious And Effective?

Comparative studies and clinical trials provide evidence of the effectiveness of acetaminophen and ibuprofen. Research suggests (9) that ibuprofen yields better results when relieving inflammatory pain conditions than acetaminophen.

What sets these two medicines apart is that ibuprofen is an anti-inflammatory drug, while acetaminophen is used mostly for analgesia (pain reliever). While both of the drugs can be used for pain reduction purposes, only ibuprofen can help reduce inflammation.

Efficacy In Pain Relief

Comparative studies for acetaminophen and ibuprofen (9)

Effective in relieving mild to moderate pain.Effective in relieving mild to moderate pain.
Comparative studies suggest that it is less effective in pain relief due to inflammation.Ibuprofen provides better pain relief compared to acetaminophen in certain conditions.
Less effective in treating arthritis and osteoarthritis.Effective treating arthritis and osteoarthritis.

Efficacy In Reducing Fever

Comparative studies for acetaminophen and ibuprofen (9)

Effective in reducing fever.Effective in reducing fever.
Less effective in case of inflammation or raised body temperature due to infections.Helpful in case of inflammation or raised body temperature in case of infections.

Use During Pregnancy And Lactation


Acetaminophen is safe during pregnancy and for breastfeeding moms. During the first trimester, it is advisable to consult a healthcare professional (10). It may not cause severe adverse effects if recommended doses and guidelines are followed and taken according to healthcare professionals’ advice.


Ibuprofen is contraindicated in the third trimester of pregnancy. It has been studied that it may increase the risk of complications in both the mother and the fetus, such as ductus arteriosus and renal dysfunction. Ibuprofen can cross barriers, pass into breast milk during breastfeeding, and harm the infant. Pregnant and breastfeeding moms should consult their healthcare professionals before taking this pain reliever. (11)

Use In Specific Populations

Acetaminophen is safe for children and infants. It is the most widely used painkiller and antipyretic in this population. If a person is allergic to acetaminophen, then it should be avoided as it may cause an allergic reaction, which may even prove lethal. Otherwise, it does not cause serious side effects if taken with appropriate dosing based on age and weight (12, 13).

Ibuprofen is generally not recommended for use in infants younger than six months old due to potential toxic effects. Pediatric dosing guidelines should be followed for children and infants before taking this medication (14).

Elderly patients who have compromised liver and kidney function or any other comorbidities should consult their doctors before taking acetaminophen and ibuprofen due to the higher risk of adverse events as their clearance from the body is impaired, and the medication should be given at adjusted regimens. (15).


The efficacy levels, dosage recommendations, drug interactions, and contraindications between both medications differ notably.

Acetaminophen is good for mild to moderate pain relief and fever reduction. It does not possess significant anti-inflammatory characteristics. Its mode of action concentrates on the central nervous system, making it safe primarily when taken according to the recommendation.  Liver damage can result if doses exceed the recommended threshold.

On the other hand, Ibuprofen presents anti-inflammatory effects. It delivers favorable results for managing various medical conditions, including arthritis. Nevertheless, its side effects profile holds a greater risk for potential gastrointestinal side effects at high doses or long-term therapy, along with increased cardiovascular risks.

See Also

When You Should and Shouldn’t Use Acetaminophen?

Definition of Anti-inflammatory Medications?

Is Tylenol a Blood Thinner?

Ibuprofen Contraindications You Have to Know

Is Ibuprofen a Blood Thinner?

Can Abilify Cause Weight Gain?

Current Version
July 27, 2023
Written By
Daniyal Haider, MD
Medically Reviewed By
Franco Cuevas, MD
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