Acetaminophen vs. Ibuprofen

Acetaminophen vs. ibuprofen are generic names for over-the-counter (OTC) pain relief drugs. They work differently in the body.

Acetaminophen and ibuprofen are pain-relief medicines that work differently. Ibuprofen has the added benefit of reducing inflammation. (Photo Credit: iStock/Getty Images)

In the U.S., acetaminophen is the common name for N-acetyl-para-aminophenol (APAP). In other countries, it may be called paracetamol. It's a non-opioid analgesic, which means that it reduces pain signals in your nervous system. It's also an antipyretic agent, which means it reduces fever.

Uses of acetaminophen

Doctors recommend it for mild-to-moderate pain relief in conditions such as:

Backaches

Colds

Headaches

Period pain

Minor arthritis pain

Muscle aches

Sore throat

Toothache

Reactions to vaccines

You can also take it to reduce fever.

How does acetaminophen work?

Experts don't know exactly how acetaminophen works in people. In mice, it blocks part of the cyclooxygenase (COX) pathway in the central nervous system. So it probably works the same way in humans.

By blocking the COX pathway, it keeps your nervous system from making a molecule called prostaglandin. Prostaglandin is a signal your body makes when you have tissue damage or infection. It's involved in, among other things, pain perception. 

Acetaminophen dosage

Follow the dosage recommended by your doctor and as directed on the label. In general, the recommended dosage for adults and teens aged older than 13 is:

For people weighing 110 pounds and over: 1,000 milligrams every 6 hours or 650 milligrams every 4 hours. Don't take more than 1,000 milligrams in a single dose. Don't take it more often than every 4 hours. Don't take more than 4,000 milligrams per day.

For people weighing less than 110 pounds: 12.5 milligrams per 2.2 pounds of body weight every 4 hours or 15 milligrams per 2.2 pounds every 6 hours. Don't take more than 15 milligrams per 2.2 pounds of body weight in a single dose. Don't take it more often than every 4 hours. Don't take more than 3,750 milligrams per day or 75 milligrams per 2.2 pounds of body weight, whichever is lower.

Taking more than the recommended dosage can cause severe liver damage.

Acetaminophen is also added to some prescription medicines. Talk to your doctor if you're also taking any prescription medicines or other OTC drugs for pain, fever, coughs, and colds. Do not take acetaminophen with other medicines containing acetaminophen because an overdose could be fatal. 

Common acetaminophen brand names

In the U.S., acetaminophen is found in hundreds of brands. Common ones include:

Dayquil

Feverall

Mapap and Children's Mapap

Nyquil

Percocet

Robitussin

Silapap

Tylenol

Vicodin

What Is Ibuprofen?

Ibuprofen is one of the most widely used nonsteroidal anti-inflammatory drugs (NSAIDs) in the world. As an NSAID, it's related to aspirin and naproxen. Like acetaminophen, NSAIDs reduce pain and fever. But unlike acetaminophen, they also reduce inflammation (swelling and redness). 

Uses of ibuprofen

Ibuprofen is FDA-approved for mild-to-moderate pain relief and fever reduction in conditions such as:

Any kind of arthritis

Backaches

Colds

Fever

Headaches

Period pain

Other aches and pains, especially if you also have inflammation

How does ibuprofen work?

Ibuprofen was invented in the 1960s as a way to reduce pain, swelling, and stiffness in people with rheumatoid arthritis. As with acetaminophen, ibuprofen blocks part of the cyclooxygenase (COX) pathway in your body and keeps you from making prostaglandin. Prostaglandin is a signal molecule involved in pain and swelling in your body. It's different from acetaminophen in that it not only works in your brain, but also in the rest of your body. That's how it can reduce inflammation as well as pain and fever.

Ibuprofen dosage

Different brands may have different dosage instructions, so take it as directed on the label or as recommended by your doctor. It's always best to take the lowest dose that still gives you relief from your symptoms. 

Common ibuprofen brand names

In the U.S, common brands include:

Advil

Motrin

Acetaminophen

Acetaminophen can cause an allergic reaction in your body. The signs of an acetaminophen allergy are swelling in the face, tongue, throat, and lips. You may also develop hives or have difficulty breathing. 

In some rare cases, it can cause a lethal skin reaction. This is even possible if you have never had an adverse reaction to the drug in the past. If you experience blistering, rash, redness, or peeling on your skin, stop taking the medicine and talk to your doctor right away. 

Don't drink alcohol while you're taking acetaminophen. 

Always talk to your doctor before using over-the-counter medicines if you are pregnant or have heart, kidney, or liver disease. But acetaminophen is considered safe for your baby, so your doctor will likely suggest you take it instead of ibuprofen if you need it.

Common side effects include:

Nausea

Vomiting

Headache

Ibuprofen

All NSAIDs can increase your risk of heart attack or stroke. Ask your doctor if you can take ibuprofen if you have any chronic conditions, especially kidney disease, heart disease, stomach ulcers, asthma, or have had a heart attack. You should also ask your doctor if you can take it when you are pregnant or breastfeeding because NSAIDs in the last 20 weeks of pregnancy can cause kidney and heart problems in your baby. It may also cause complications in the rest of your pregnancy.

If you have had an allergic reaction or a hypersensitivity reaction to other NSAIDs, you should avoid ibuprofen. Signs of an allergic reaction include swelling in your throat or face and itchy welts or hives.

Common side effects include:

Headache

Loss of appetite

Nausea

Upset stomach

Talk to your doctor as soon as possible if you have any of the following side effects:

Increased blood pressure

Signs of heart failure such as rapid weight gain or unusual weakness or fatigue

Skin rash, itching, or hives

Redness, blistering, peeling or loosening of your skin, including inside your mouth

Signs of liver problems such as pain in your upper right belly, light-colored poop, dark yellow or brown pee, and yellowing of your skin or eyes

Signs of kidney problems such as a decreased amount of pee or swelling in your ankles, feet, or hands

Bleeding, small red or purple spots on your skin, or unusual bruising

Signs of stroke such as sudden numbness or weakness in your face, arm, or leg on one side of your body, trouble talking, confusion, loss of balance, or headaches and dizziness

Signs of heart problems, such as pain or tightness in your chest, shoulders, arms, or jaw or cold, clammy skin

Shortness of breath with moderate activity or feelings of lightheadedness or dizziness

Bleeding and swelling in your stomach (rare compared to other NSAIDs). Signs include bloody, black, or tar-like poop or throwing up what looks like coffee grounds.

Does Ibuprofen Have Side Effects?

If you have heart disease, stomach ulcers, asthma, or have had a heart attack, ask your doctor if you can take ibuprofen. Pregnant and breastfeeding women should also consult with their doctors before taking this drug.

Like acetaminophen, you can also be allergic to ibuprofen. The signs of an allergic reaction are swelling in the throat or face.

Some other ibuprofen side effects are:

Vision changes

Shortness of breath with moderate activity 

Rapid weight gain 

Skin rash 

Liver problems 

Kidney problems 

Nausea and vomiting

Bleeding

Headaches and dizziness 

If you're confused which to use, experts generally advise you to choose ibuprofen for inflammation and acetaminophen for just pain. 

Acetaminophen vs. ibuprofen for headaches

If you aren't allergic and don't have liver problems, acetaminophen may be better for a simple headache than ibuprofen. 

Acetaminophen vs. ibuprofen for sore throat

The American Academy of Family Physicians recommends ibuprofen for a sore throat that's due to strep throat. Most cases of sore throat include inflammation as well as pain, so ibuprofen is probably the best choice in this case unless you have a reason not to take it.

Which is better for an earache?

Acetaminophen and ibuprofen will work equally well for earache, so take whichever you prefer. If you need to take pain medicine for several days in a row, though, you may want to try alternating them to help lessen the chance of getting side effects.