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Aspirin (NSAID, Antiplatelet Agent)

Written by Stephanie Nera, RPh, PharmD · Pharmacology

Updated Jul 25, 2022

    Aspirin (NSAID, Antiplatelet Agent)

    Aspirin or acetylsalicylic acid (ASA) is a nonsteroidal anti-inflammatory drug (NSAID) and anti-platelet drug or “blood thinner”. It is available for low and high-dose regimens.



    What is aspirin used for?

    How should I take aspirin?

    Read the directions on the packaging for complete information. Check the label and expiration date.

    For oral dosage forms, swallow it whole without chewing, crushing, or dissolving it in liquid. Take it with meals to prevent gastric irritation.

    How do I store aspirin?

    Store this product at room temperature away from direct light and moisture. To prevent drug damage, you should not store it in the bathroom or the freezer. 

    There may be different brands of this drug that may have different storage needs. So, it is important to always check the product package for instructions on storage, or ask your pharmacist. For safety, you should keep all medicines away from children and pets.

    You should not flush this product down the toilet or pour them into a drain unless instructed to do so. Additionally, it is important to properly discard this product when it is expired or no longer needed. Consult your pharmacist for more details about how to safely discard your product.

    Precautions & Warnings

    What should I know before using aspirin?

    Before using this drug, tell your doctor if you are/have:

    • Pregnant or breastfeeding.
    • Taking any other medicines. This includes any prescription, OTC, and herbal remedies.
    • An allergy to any of the ingredients of this product.
    • Any other illnesses, disorders, or medical conditions.

    Is it safe during pregnancy or breastfeeding?

    Salicylates are present in the umbilical cord and in breast milk after taking them. Low-dose aspirin has less adverse effects than high-dose aspirin. Pregnant women should avoid taking aspirin at 20 weeks of gestation until delivery. Other pain relievers are recommended over aspirin while breastfeeding.

    Side Effects

    What side effects can occur from aspirin?

    Like all drugs, this product may have side effects. If they occur, side effects are generally mild and resolve once treatment is finished or the dose is lowered. Some reported side effects include:

    • Upset stomach
    • Heartburn
    • Drowsiness
    • Mild headache

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

    • Tinnitus
    • Confusion
    • Hallucinations
    • Rapid breathing
    • Seizure (convulsions)
    • Severe nausea
    • Vomiting
    • Stomach pain
    • Bloody or tarry stools
    • Coughing up blood or vomit that looks like coffee grounds
    • Fever lasting longer than 3 days
    • Swelling, or pain lasting longer than 10 days

    However, not everyone experiences these side effects. In addition, some people may experience other side effects. So, if you have any concerns about a side effect, please consult your doctor or pharmacist.


    What drugs may interact with aspirin?

    This medication may interact with other drugs that you are currently taking, which can change how your drug works or increase your risk for serious side effects. 

    To avoid any potential drug interactions, you should keep a list of all the drugs you are using (including prescription drugs, nonprescription drugs, and herbal products) and share it with your doctor and pharmacist. 

    Drugs with known interactions:

    • Corticosteroids
    • Anticoagulants
    • Antiplatelet agents
    • Carbonic anhydrase inhibitors
    • Sulfonylureas
    • Phenytoin, valproate
    • Probenecid, sulfinpyrazone
    • Lithium
    • Digoxin
    • Other NSAIDs
    • Methotrexate
    • Ginkgo biloba

    If you experience an adverse drug interaction, inform your doctor immediately to reevaluate your treatment plan. Approaches include dose adjustment, drug substitution, or ending therapy.

    Does food or alcohol interact with aspirin?

    This drug may interact with food or alcohol by altering the way the drug works or increase the risk for serious side effects. Avoid consuming alcohol while taking this drug to prevent gastric irritation. Please discuss with your doctor or pharmacist any potential food or alcohol interactions before using this drug.

    What health conditions may interact with aspirin?

    This drug may interact with underlying conditions. This interaction may worsen your health condition or alter the way the drug works. Therefore, it is important to always let your doctor and pharmacist know all the health conditions you currently have, especially:

    • Active bleeding
    • Ulcers
    • Bleeding disorders
    • Viral infections (in children)


    The information provided is not a substitute for any medical advice. Therefore, you should always consult with your doctor or pharmacist before using any medication.

    What is the dose for an adult?

    Analgesic and antipyretic

    Take 325 mg to 1 g every 4 to 6 hours, as needed, up to 4 g per day.


    Take 4 to 8 g per day in 4 to 5 divided doses, as needed. Adjust the dose based on response and tolerability. Continue treatment until symptoms resolve (typically 1 to 2 weeks, but potentially up to 8 weeks).

    Atherosclerotic cardiovascular disease

    Take 75 to 100 mg once a day.


    Take 900 mg or 1 g as one dose, as needed.


    Initially, take 650 mg to 1 g every 8 hours until resolution of symptoms. Then, gradually taper off over several weeks by decreasing the dose by 250 to 500 mg every 1 to 2 weeks.


    Take 81 to 162 mg once a day, ideally starting between 12 to 16 weeks of gestation. It can be started up to 28 weeks of gestation. Continue therapy until delivery.


    Take 75 to 100 mg once a day.

    What is the dose for a child?

    Do not give aspirin to children under 18 years old who have or recently had a viral infection. This is to avoid the development of Reye syndrome, which is potentially fatal.

    Children ≥12 years and weighing ≥50 kg: Give 325 to 650 mg every 4 to 6 hours. The maximum daily dose is 4,000 mg.

    Children weighing <50 kg: Limited data is available: Give 10 to 15 mg/kg/dose every 4 to 6 hours. The maximum daily dose is 90 mg/kg/day or 4,000 mg/day whichever is less.

    How is aspirin available?

    Aspirin is available in the following dosage forms and strengths:

    • Caplet: 81 mg, 325 mg, 500 mg
    • Capsule: 162.5 mg, 325 mg
    • Rectal suppository: 300 mg, 600 mg
    • Tablet: 81 mg, 325 mg
    • Chewable tablet: 81 mg

    What should I do in case of an emergency or overdose?

    In case of an emergency or an overdose, call your local emergency services or go to the nearest emergency room.

    What should I do if I miss a dose?

    If you miss a dose, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and take your regular dose as scheduled. Do not take a double dose.


    Hello Health Group does not provide medical advice, diagnosis or treatment.

    Written by

    Stephanie Nera, RPh, PharmD


    Updated Jul 25, 2022

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