Acetaminophen vs Aspirin – Uses, Dosage, Side Effects, Differences

Acetaminophen is a drug used to reduce fever and relieve pain.

The most popular brand name of this medication is called Tylenol. Also, it is sold under the brand names of Mapap and Panadol.

This painkiller has been sold in the United States since the 1950s. It has been the most widely-used OTC medicine in the US since the mid-2000s. More than 50 million Americans use it every week.

It belongs to a group of drugs called antipyretics and analgesics. These medicines work by changing the way the human body feels pain and by cooling the body.

Note – acetaminophen is the name used in Japan and the US, however, internationally, it is known as paracetamol.


It is an OTC pain reliever that may be used to help with mild to moderate muscle aches, headaches, sore throats, backaches, toothaches, menstrual cramps, and reactions to vaccines.

This medication is both a prescription or an over-the-counter medication. However, both forms of the drug are used to reduce fever and to treat mild to moderate pain.


It comes in different forms – chewable tablets, tablets, capsules, disintegrating tablets (dissolves on the tongue), suppositories, and liquid.

The usual dose for adults and children over 12 years old is 2 tablets every 4-6 hours. The Food and Drug Administration has set the recommended maximum dose for adults at 3,000 milligrams a day.

Side Effects

Common side effects may include:

  • dizziness;
  • drowsiness;
  • sour stomach;
  • mild stomach pain;
  • nausea without or with vomiting;
  • diarrhea;
  • constipation.

Rare side effects may include:

  • pain, swelling, or tenderness in the stomach area;
  • a sore throat;
  • fever;
  • stomach cramps;
  • breathing problems;
  • vomiting;
  • itching or hives;
  • swelling of the lips, face, or tongue;
  • skin rash;
  • loss of appetite;
  • increased sweating;
  • yellowing of the eyes or skin;
  • unusual weakness;
  • unusual bruising;
  • trouble passing urine;
  • loosening of the skin, including inside the mouth.

This medication may interact with:

  • seizure medications;
  • nonsteroidal anti-inflammatory drugs;
  • medicines to treat psychiatric disorders;
  • HIV/AIDS medications;
  • arthritis medications (including gold injections);
  • LDL cholesterol-lowering medications;
  • cancer medications;
  • high blood pressure medication;
  • birth control pills;
  • tuberculosis medicines;
  • antifungals;
  • antibiotics.

This drug may also harm the kidney or liver. This risk is considerably higher if alcoholic beverages are consumed while this drug is used.


It is the brand name of a drug called – acetylsalicylic acid (ASA). It is typically used to reduce minor pains and aches, inflammation, and fever. In long-term low doses, it is used as an antiplatelet for people at high risk of stroke or heart attack. Also, it is occasionally found in combination with pain relievers, antacids, or cold medication.

Acetylsalicylic acid and other nonsteroidal anti-inflammatory drugs work by decreasing the human body’s production of enzymes that create pain-related chemicals, hence, reducing the symptoms of pain and inflammation.

It was the 1st OTC pain reliever medicine to be mass-produced. For instance, in 1900, it was sold as a powder, and in 1915, the first tablets were produced.


ASA is typically used for period pains, headaches, strains and sprains, flu and colds, and long-term conditions (like – arthritis).

A low dose of acetylsalicylic acid (total dose of 75 to 300 mg a day) is used as a blood thinner to help prevent strokes and heart attacks in people who have a high risk of these life-threatening conditions.

Moreover, there is some evidence that acetylsalicylic acid may reduce the risk of developing cancer, particularly colorectal cancer.

Also, it may be prescribed for children to treat Kawasaki disease (a rare illness that affects the blood vessels) or after heart surgery. However, this medicine shouldn’t be given to anyone under 16 years old without a doctor’s recommendation.


To treat fever or pain in adults, the recommended dose is 325 mg to 650 mg every 4 to 6 hours. The maximum daily dose is 3,000 mg unless otherwise directed by a healthcare professional. Unless a healthcare specialist has prescribed it, this medicine must not be given to children under the age of 16 years.

Side Effects

Common side effects may include:

  • constipation;
  • diarrhea;
  • heartburn;
  • nausea;
  • abdominal discomfort;
  • swollen ankles;
  • fluid retention;
  • fatigue;
  • drowsiness;
  • blurred vision;
  • ringing in the ears;
  • dizziness.

Symptoms of chronic overdose may include:

  • uncontrollable rapid breathing;
  • rapid heartbeat;
  • confusion;
  • fatigue.

Do not take this drug with any of the following:

  • probenecid;
  • ketorolac;
  • varicella live vaccine;
  • cidofovir;
  • alcohol;
  • ibuprofen or naproxen;
  • alendronate;
  • pemetrexed;
  • sulfinpyrazone;
  • bismuth subsalicylate;
  • warfarin;
  • ticlopidine;
  • heparin;
  • enoxaparin;
  • methazolamide;
  • acetazolamide;
  • flavocoxid.

Regular use of this medicine can destroy the lining of your gastrointestinal tract, therefore, it may increase the risk for:

  • intestinal perforations;
  • inflammatory bowel disease;
  • diverticular disease;
  • Crohn’s disease;
  • H. Pylori infection;
  • duodenal ulcers.

Taking this drug during late pregnancy may cause bleeding in the mother or the baby during delivery. Because it has a mild tendency to interfere with blood clotting, this drug should be discontinued before elective surgery, at least 2 weeks in advance of the procedure.

Acetaminophen vs Aspirin – Differences

Acetaminophen is a centrally acting antipyretic and analgesic agent. It is not considered a nonsteroidal anti-inflammatory drug due to its negligible anti-inflammatory attributes. On the other hand, aspirin is an antiarthritic, antiplatelet, and anti-inflammatory agent (depending on the dosage).

Acetaminophen doesn’t generally cause stomach disorders as with aspirin, but too much may increase the risk of liver damage. For both drugs, the side effects increase if alcohol is consumed.

Images credit – Shutterstock & Getty

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