Diclofenac vs. Aspirin

See how Diclofenac and Aspirin compare on approved uses, dosing, side effects, and cost.

Key Takeaways

  • Diclofenac is a prescription-strength NSAID for arthritis and moderate pain, while aspirin is an over-the-counter option also used to help prevent heart attack and stroke.

  • Diclofenac carries a boxed warning for cardiovascular risk in addition to the stomach bleeding risk both drugs share, since it works differently in the body at anti-inflammatory doses.

  • Diclofenac is dosed by prescription two to three times daily for arthritis, while aspirin dosing ranges from occasional pain relief to a once-daily low dose for heart protection.

Diclofenac vs. Aspirin Drug Summary

Diclofenac

Diclofenac is a prescription NSAID used to relieve pain and inflammation from osteoarthritis, rheumatoid arthritis, ankylosing spondylitis, and menstrual cramps. It comes as a delayed-release oral tablet taken two to three times a day, with dosing adjusted based on the condition being treated.

Aspirin

Aspirin is an over-the-counter NSAID and salicylate used for pain, fever, and inflammation, and at low daily doses to help prevent heart attack and stroke. It comes in regular, chewable, and enteric-coated tablets, with dosing that ranges from occasional pain relief to once-daily cardiovascular protection.

Diclofenac vs. Aspirin Side Effects

Diclofenac

Most common
abdominal pain (about 20%)
diarrhea (1-10%)
edema/fluid retention (1-10%)
headache (up to 7%)

Aspirin

Most common
stomach upset (common)
heartburn (common)
easy bruising/bleeding (common)
gi bleeding (uncommon but serious)

Diclofenac vs. Aspirin Dosage

Diclofenac

Dosage
Dosage Table
STAGE DOSE WHEN
Starting dose 50 mg two-three x daily At the start
Maximum dose 150 mg/day maximum If needed
Dose changes 3 increases As tolerated

Aspirin

Dosage
Dosage Table
STAGE DOSE WHEN
Starting dose 325-650 mg every 4 hrs At the start
Maximum dose 75-325 mg once daily If needed
Dose changes 2 increases As tolerated

Diclofenac vs. Aspirin Indications

Diclofenac

Diclofenac is FDA-approved for painful inflammatory conditions like osteoarthritis and rheumatoid arthritis, as well as ankylosing spondylitis and primary dysmenorrhea. It is also approved for short-term treatment of mild to moderate acute pain. It is not approved for use in children or for pain around CABG heart surgery.

  • Osteoarthritis pain and inflammation

  • Rheumatoid arthritis pain and inflammation

  • Ankylosing spondylitis

  • Primary dysmenorrhea

Aspirin

Aspirin is FDA-approved for temporary relief of minor aches, pain, and fever, and for reducing the risk of heart attack and stroke in people with cardiovascular disease. It is also used for rheumatologic conditions such as rheumatoid arthritis. It is not approved for children or teens with viral illnesses due to Reye's syndrome risk.

  • Minor aches, pain, and fever relief

  • Secondary prevention of heart attack and stroke

  • Reducing risk in unstable angina and acute MI

  • Rheumatologic conditions like rheumatoid arthritis

Diclofenac vs. Aspirin Pros and Cons

Diclofenac

Diclofenac provides stronger, more targeted anti-inflammatory relief for arthritis and related conditions than standard aspirin doses, but it carries boxed warnings for cardiovascular and gastrointestinal risk. Most oral formulations require a prescription, and periodic liver monitoring is often recommended.

Pros

  • Stronger anti-inflammatory effect for arthritis pain

  • Available in oral, topical, ophthalmic, and injectable forms

  • FDA-approved specifically for rheumatoid arthritis and ankylosing spondylitis

  • Once or twice daily dosing options for steadier symptom control

Cons

  • Boxed warning for heart attack and stroke risk

  • Requires a prescription for oral tablets

  • Needs periodic liver enzyme monitoring

  • Roughly $7 to $110 per month without insurance, more than aspirin

Aspirin

Aspirin is inexpensive, available without a prescription, and is the only common OTC pain reliever with an FDA-recognized use for preventing heart attack and stroke. It is generally less potent for chronic inflammatory arthritis pain, and frequent dosing is needed for pain relief.

Pros

  • Available over the counter without a prescription

  • Only OTC analgesic FDA-approved for cardiovascular event prevention

  • Decades of established safety data

  • Roughly $2 to $15 per month, much less than diclofenac

Cons

  • Less potent for chronic inflammatory arthritis pain at OTC doses

  • Needs dosing every 4 hours for ongoing pain relief

  • Risk of Reye's syndrome in children and teens with viral illness

  • Tinnitus (ringing in ears) can occur at higher doses

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