From the Guidelines
No, diclofenac is not the same as acetylsalicylic acid (aspirin), as they belong to different chemical groupings within the nonsteroidal anti-inflammatory drugs (NSAIDs) class, with distinct pharmacological effects and side effect profiles. They are different medications that belong to the same broad class of drugs called non-steroidal anti-inflammatory drugs (NSAIDs), but they have distinct chemical structures and some differences in their effects. According to the study published in Circulation 1, diclofenac and aspirin are classified under different categories, with aspirin being a salicylic acid derivative and diclofenac being an acetic acid derivative.
Key Differences
- Diclofenac (brand names include Voltaren, Cataflam) is a more potent NSAID often prescribed for conditions like arthritis, while aspirin (acetylsalicylic acid) is available over-the-counter and commonly used for pain relief, fever reduction, and in low doses for heart attack prevention.
- They work similarly by inhibiting enzymes called cyclooxygenases that produce inflammatory chemicals in the body, but diclofenac tends to have stronger anti-inflammatory effects than aspirin.
- The side effect profiles also differ somewhat - aspirin has more anti-platelet (blood-thinning) effects and is more likely to cause stomach bleeding at regular doses, while diclofenac may have a higher risk of cardiovascular side effects with long-term use, as suggested by the MEDAL program which reported noninferiority of etoricoxib compared with diclofenac with regard to cardiovascular thrombotic events 1.
Clinical Implications
- These medications are not interchangeable, and you should always follow your healthcare provider's specific recommendations about which NSAID is appropriate for your condition.
- The choice between diclofenac and aspirin should be based on individual patient needs, medical history, and the specific condition being treated, considering the potential benefits and risks of each medication, as outlined in the study published in Circulation 1.
From the Research
Comparison of Diclofenac and Acetylsalicylic Acid (Aspirin)
- Diclofenac and acetylsalicylic acid (aspirin) are both nonsteroidal anti-inflammatory drugs (NSAIDs) but they have different properties and uses 2, 3.
- Aspirin was the first NSAID introduced in 1899, and it was initially used for its analgesic and antipyretic properties, while diclofenac is a more recently developed NSAID with a broader range of indications, including osteoarthritis, rheumatoid arthritis, and other forms of arthritis 3.
- Both diclofenac and aspirin work by inhibiting cyclooxygenase (COX) enzymes, which are involved in the production of prostaglandins, but they have different mechanisms of action and potencies 4, 3.
- Diclofenac has been shown to have a more favorable safety profile compared to some other NSAIDs, with a lower incidence of gastrointestinal side effects and other adverse reactions 5.
- Aspirin, on the other hand, has a unique property of irreversibly inhibiting platelet aggregation, which makes it useful for cardiovascular protection, but this effect can be antagonized by concomitant use of certain other NSAIDs, such as ibuprofen 6.
- Diclofenac does not appear to have any unusual adverse reactions, and its safety profile is similar to that of other NSAIDs, with the most common side effects being gastrointestinal and renal problems 5.
Key Differences
- Mechanism of action: Diclofenac has a more complex mechanism of action, involving multiple pathways, while aspirin's mechanism is primarily related to COX inhibition 4.
- Indications: Diclofenac is used for a broader range of conditions, including chronic pain and inflammatory diseases, while aspirin is often used for acute pain, fever, and cardiovascular protection 2, 3.
- Safety profile: Diclofenac has a more favorable safety profile compared to some other NSAIDs, while aspirin's use is limited by its potential for gastrointestinal toxicity and bleeding complications 5.