Aspirin vs Acetaminophen

Listen to the article instead of reading through it.


For patients with pain, inflammation, or fever, certain drugs that inhibit the production of chemicals in the body linked to these symptoms can provide significant relief and manage symptoms effectively. Aspirin and Acetaminophen are two such drugs commonly used for these purposes. Both have analgesic and antipyretic effects, but their mechanisms of action and side effects differ. Aspirin is classified as a nonsteroidal anti-inflammatory drug (NSAID) and works by reducing the production of substances in the body that cause pain and inflammation. It is also used as an antiplatelet drug to reduce the risk of heart attack and stroke. On the other hand, Acetaminophen, also known as paracetamol, primarily works in the brain to inhibit chemical messengers responsible for pain and fever signals. Unlike Aspirin, it has minimal anti-inflammatory effects and does not contribute to blood thinning.

What is Aspirin?

Aspirin (also known as acetylsalicylic acid) was the first drug in the class of nonsteroidal anti-inflammatory drugs (NSAIDs), which represented a significant advancement from traditional pain relief medications. Aspirin was first accepted by the FDA in 1899. Aspirin works by reducing substances in the body that cause pain, fever, and inflammation. It is often prescribed for the relief of mild to moderate pain, fever, and inflammatory conditions such as rheumatoid arthritis. Aspirin also has an effect on platelets in the blood which prevents them from aggregating and is therefore used in the prevention of heart attacks and strokes.

On the other hand, acetaminophen (also known as paracetamol and sold under the brand name Tylenol among others) is a different class of drug used to relieve mild to moderate pain and to reduce fever. Unlike aspirin, it doesn't have any significant anti-inflammatory effect and doesn't affect platelet function, so it is not used to treat inflammatory conditions or in cardiovascular disease prevention. Acetaminophen is generally seen as having fewer side effects compared to aspirin, especially related to gastrointestinal issues, but overdosing can lead to severe liver damage.

What conditions is Aspirin approved to treat?

Aspirin and Acetaminophen are approved for the treatment of various conditions:

  • Aspirin is used to relieve pain, fever, and inflammation. It's also recommended by doctors at low doses to prevent heart attacks in people who've had one before or who have a high risk of having one.

  • Acetaminophen is primarily used to treat pain and reduce fever. It doesn't decrease inflammation like aspirin does, but it's less likely than aspirin to cause gastrointestinal problems or interfere with blood clotting.

How does Aspirin help with these illnesses?

Aspirin helps manage pain, inflammation, and fever by inhibiting the production of prostaglandins in the body. Prostaglandins are substances known to promote inflammation, pain sensation, and increase body temperature during instances of infection or injury. Aspirin blocks an enzyme called cyclooxygenase (COX) which is responsible for making prostaglandins. By doing so, it reduces these symptoms providing relief to patients.

On the other hand, acetaminophen also lessens discomfort from pain and reduces fever but does not have strong anti-inflammatory properties like aspirin. The exact mechanism through which acetaminophen works is still not completely understood. However, some believe that it may inhibit a specific variant of the COX enzyme found mainly within the brain.

So while both medications can alleviate pain and lower fever effectively, if there's significant inflammation involved such as with arthritis or injury – aspirin would potentially be more beneficial given its additional anti-inflammatory effect.

What is Acetaminophen?

Acetaminophen, also known as paracetamol and sold under the brand name Tylenol among others, is a medication used to treat pain and fever. It is typically used for mild to moderate pain relief. Evidence is mixed for its use to relieve fever in children. It is often sold in combination with other medications, such as in many cold medications. Acetaminophen is classified as a mild analgesic and is not an NSAID like aspirin, meaning it doesn't reduce inflammation. It works by inhibiting a specific enzyme in the brain and central nervous system, reducing the production of prostaglandins and therefore reducing pain and fever. Acetaminophen was first approved by the FDA in 1951. Its lack of anti-inflammatory action means that its side-effect profile is also different to that of NSAIDs, particularly in that it is less likely to cause gastrointestinal bleeding and ulcers (common side effects of NSAIDs like aspirin). The effects of acetaminophen can be beneficial for the treatment of pain, especially in patients who do not respond well to the “typical” NSAID drugs such as aspirin.

What conditions is Acetaminophen approved to treat?

Acetaminophen is a common over-the-counter medication that has been approved by the FDA for the treatment of:

  • Mild to moderate pain, such as headaches, muscle aches, backache, toothaches and menstrual cramps
  • Fever reduction While it does not have the anti-inflammatory properties like aspirin, Acetaminophen works effectively in managing these symptoms without causing stomach upset or increasing bleeding risk.

How does Acetaminophen help with these illnesses?

Acetaminophen, similar to aspirin, is a common analgesic and antipyretic medication widely used to alleviate pain and reduce fever. It works by inhibiting an enzyme in the brain responsible for producing prostaglandins, which are substances that cause pain and inflammation in response to injury. Acetaminophen acts primarily in the central nervous system, making it particularly effective for reducing pain and fever. However, unlike aspirin, acetaminophen does not have significant anti-inflammatory effects, and thus, it may not be as effective in treating conditions where inflammation is a primary symptom. Additionally, acetaminophen is typically easier on the stomach than aspirin, and therefore is often chosen for patients who have a history of gastric issues. It's also the preferred choice when the patient has blood clotting disorders or is on anticoagulant therapy, as it does not affect platelet function the way aspirin does.

How effective are both Aspirin and Acetaminophen?

Both aspirin and acetaminophen (Tylenol) have proven track records in managing pain and reducing fever, making them staples in many households. While they were introduced several decades apart — aspirin was first synthesized in 1897, while acetaminophen became available over-the-counter only in the 1950s — both are highly trusted by medical professionals worldwide due to their efficacy and safety profiles.

Aspirin is known for its analgesic, antipyretic, anti-inflammatory properties as well as its ability to inhibit blood clotting. A clinical trial conducted in 1991 demonstrated that low-dose aspirin could significantly reduce the risk of heart attack or stroke among high-risk individuals. However, this same property makes it less suitable for people with bleeding disorders or peptic ulcer disease.

Acetaminophen shares similar analgesic and antipyretic capabilities but lacks the anti-inflammatory and blood-thinning effects of aspirin. This makes it an ideal choice for those who cannot take NSAIDs like aspirin due to gastric irritation or those at risk of bleeding complications.

Research from a meta-analysis conducted in 2004 indicated that when used within recommended dosages, both medications exhibited favorable side effect profiles with minimal risks involved. Aspirin has been widely used across various age groups including seniors; however caution must be exercised when administering it to children under 16 due to the risk of Reye's syndrome.

A recent review from 2016 suggested that while both drugs are effective against pain and fever, acetaminophen may be considered a better first-line medication because of its lower likelihood of causing gastrointestinal distress or increasing bleeding tendencies unlike NSAIDs such as aspirin. However, owing to its unique pharmacology particularly regarding cardiovascular protection offered by low-dose regimen ,aspirin remains an invaluable tool especially among patients suffering from coronary artery diseases.

abstract image of a researcher studying a bottle of drug.

At what dose is Aspirin typically prescribed?

Oral dosages of Aspirin for adults range from 325-650 mg every 4 hours or 500-1000 mg every 6 hours. Dosage can be increased after a few weeks if there is no response, but the maximum dosage should not exceed 4000 mg in any given day. For Acetaminophen, oral dosages for adults are typically between 325–650mg taken every four to six hours as needed, with a daily limit of 3000mg unless advised otherwise by your healthcare provider. Children's doses vary based on weight and age; consult with their pediatrician before administration. In either case, these medications should always be taken as directed by your doctor or according to package instructions.

At what dose is Acetaminophen typically prescribed?

Acetaminophen treatment usually begins with a dosage of 325-650 mg every 4 to 6 hours. The dose can be increased to a maximum of 1000 mg per single dose, taken no more frequently than every four hours. It's important not to exceed the maximum daily limit of 4000 mg in a day, divided into several doses spaced at least four hours apart. This is because exceeding this amount may lead to liver damage or other serious health problems. If there is no relief from symptoms after taking the initial dosages for a few days, it would be wise to consult with your healthcare provider for further advice.

What are the most common side effects for Aspirin?

Common side effects of Aspirin and Acetaminophen include:

  • Nausea
  • Stomach pain or discomfort
  • Heartburn, indigestion
  • Increased bleeding time (more common with aspirin)
  • Vomiting
  • Loss of appetite
  • Rash (less common)
  • Drowsiness or sleepiness (more common with acetaminophen)

It's important to remember that while these are relatively mild drugs, they can cause serious problems if taken in large doses or for an extended period. Always consult a healthcare professional before starting any new medication regimen.

abstract image of a patient experiencing side effect

Are there any potential serious side effects for Aspirin?

In rare cases, both aspirin and acetaminophen can cause serious side effects. For Aspirin these may include:

  • Signs of a severe allergic reaction such as hives; difficulty breathing; swelling of your face, lips, tongue, or throat
  • Symptoms of stomach bleeding - bloody or black stools, coughing up blood or vomit that looks like coffee grounds.
  • Liver problems - nausea, upper stomach pain, itching, tired feeling, loss of appetite.
  • Low red blood cells (anemia) – pale skin and shortness of breath.

For Acetaminophen these may include:

  • Skin rash with blistering and peeling.
  • Changes in the color of your urine.
  • Nausea followed by pain in your upper stomach area which could be signs liver damage Severe headache accompanied by dizziness Sudden changes in vision (blurred vision/seeing halos around lights).

If you experience any symptoms mentioned above while taking either aspirin or acetaminophen it is important to seek immediate medical attention.

What are the most common side effects for Acetaminophen?

Acetaminophen, while generally well-tolerated, can sometimes cause side effects such as:

  • Mild headache or stomach pain
  • Loss of appetite
  • Nausea or vomiting
  • Upset stomach followed by constipation
  • Dryness in the mouth and throat
  • Sleep problems (insomnia) due to discomfort if it's being used for pain relief
  • Rash, although this is less common.

More serious side effects include confusion or weakness which are extremely rare but require immediate medical attention. Unlike aspirin, acetaminophen does not typically result in ringing in the ears or increased urination. It's also worth noting that long-term use of high doses of acetaminophen can lead to liver damage. Always follow dosage instructions carefully when using this medication.

Are there any potential serious side effects for Acetaminophen?

While Acetaminophen is generally safe for use, it can cause serious side effects in rare instances. If you experience any of the following symptoms after taking Acetaminophen, seek medical help immediately:

  • Signs of a skin reaction such as hives, itching or a rash
  • Swelling or puffiness in your face, throat or tongue that causes difficulty breathing
  • A severe and sudden onset headache or changes in vision
  • Weakness on one side of the body which could be indicative of a stroke
  • Changes to your mental state such as confusion or mood swings
  • Experiencing unusual bleeding patterns – this might include nosebleeds, blood spots under the skin appearing like a rash (purpura), bloody stools or dark-colored urine
  • An irregular heart rate which may feel too fast, too slow or uneven.

These are not common reactions to Acetaminophen but can occur if an allergic reaction takes place. As always consult with healthcare professionals before starting any new medication regimen.

Contraindications for Aspirin and Acetaminophen?

Both aspirin and acetaminophen, like many other pain relievers and fever reducers, can cause side effects or exacerbate certain health conditions in some individuals. If you notice any abnormal reactions such as uncontrolled bleeding, severe nausea or vomiting, persistent headache or ringing in the ears while using either of these medications, it is crucial to seek immediate medical attention.

Neither aspirin nor acetaminophen should be taken if you are consuming alcohol regularly or suffer from liver disease without first consulting your physician. Aspirin also poses a risk for those with stomach ulcers or bleeding problems. Always inform your doctor about all the medications and supplements you are taking; certain drugs may interact harmfully with both aspirin and acetaminophen. For instance, blood thinners will require careful monitoring when used alongside aspirin due to an increased risk of excessive bleeding.

How much do Aspirin and Acetaminophen cost?

For the brand-name versions of these drugs:

  • The price of 100 tablets of Bayer Aspirin (325 mg) averages around $7, which works out to approximately $0.07/day depending on your dose.
  • The price for 100 tablets of Tylenol (500 mg), a well-known brand name for acetaminophen, is about $10, working out to roughly $0.10/day.

If you are taking higher dosages for pain relief or fever reduction (up to 4000mg per day for Acetaminophen; up to 4000mg per day for aspirin in divided doses), then the cost difference between them becomes more apparent but remains relatively small.

For generic versions, costs are even lower:

  • Generic aspirin can be found at prices as low as $2-$4 for a bottle containing 100 tablets (325mg each). That's just about $0.02 - $0.04 per tablet or daily dosage.
  • Generic acetaminophen is also very affordable and usually costs around $2 - $5 dollars per bottle containing 100 tablets at a strength of 500mg each ($0.02 - $0.05/tablet).

It's important to remember that while cost comparison can aid in decision-making, it should not be the primary factor when choosing between medications like aspirin and acetaminophen because they have different uses and side effects profiles that need consideration too.

Popularity of Aspirin and Acetaminophen

Aspirin, also known by its generic name acetylsalicylic acid, is a well-known and frequently used medication worldwide. It has been prescribed for various uses such as pain relief and fever reduction, but it is increasingly recognized for its role in cardiovascular health. In 2020 alone, aspirin was estimated to have been used by about 29 million people in the US.

Acetaminophen (also known as paracetamol), like aspirin, is a common over-the-counter drug widely used for relieving pain and reducing fever. Its usage surpasses that of Aspirin with an estimated consumption by around 52 million people in the US during 2020.

While both drugs are utilized for similar basic ailments such as headaches or minor pains, they have significant differences; notably Acetaminophen lacks the anti-inflammatory properties of Aspirin and does not contribute to blood thinning which makes Aspirin valuable in preventing heart attacks and strokes.


Both aspirin and acetaminophen have been extensively used for many years in managing pain and reducing fever. They are backed by a plethora of clinical studies showing their effectiveness compared to placebo treatments. Due to their different mechanisms of action, with aspirin acting primarily as an anti-inflammatory agent through inhibition of prostaglandins, and acetaminophen acting primarily on the central nervous system to decrease the perception of pain, they tend to be used under different circumstances.

Aspirin is generally considered when there's a need for both analgesic (pain relief) and anti-inflammatory effect, whereas acetaminophen would typically be chosen for its analgesic properties or if an individual cannot tolerate NSAIDs like aspirin due to stomach issues. Both drugs are available over-the-counter which provides significant cost savings especially for patients who must pay out-of-pocket.

In terms of side effects, while both drugs are usually well-tolerated at recommended doses; however, long-term use or high doses can potentially lead to serious complications such as liver injury with acetaminophen and gastrointestinal bleeding with aspirin. Furthermore, unlike acetaminophen, regular use of low-dose aspirin is often prescribed as a preventive measure against heart attacks or strokes in individuals at risk. It is always recommended that before beginning any new medication regimen including these two drugs patients should consult with their physician.