What are the most common side effects of oral diclofenac (Non-Steroidal Anti-Inflammatory Drug, NSAID)?

From the Guidelines

The most common side effects of oral diclofenac include gastrointestinal issues, such as stomach pain, heartburn, nausea, vomiting, diarrhea, and indigestion, which occur in 10 to 20 percent of users 1. These side effects are due to the inhibition of prostaglandin production, which normally protects the stomach lining. Other frequently reported side effects include:

• Headaches
• Dizziness
• Drowsiness
• Fluid retention, which may manifest as swelling in the extremities, particularly the ankles and feet
• Elevated blood pressure, especially in those with pre-existing hypertension
• Skin reactions like rash or itching More serious but less common side effects include:
• Liver function abnormalities
• Kidney problems
• Increased risk of cardiovascular events, such as heart attack or stroke, particularly with long-term use or in patients with existing heart disease The risk of side effects increases with:
• Higher doses
• Longer duration of treatment
• Older age
• Certain medical conditions To minimize these adverse effects, it is recommended to take diclofenac with food and use the lowest effective dose for the shortest necessary time. Additionally, the use of proton pump inhibitors (PPIs) or histamine H2 blockers can help reduce the risk of gastrointestinal complications, especially in high-risk patients 1. It is also important to note that the risk of gastrointestinal complications can be increased by concomitant use of anticoagulation therapy, such as warfarin, and concomitant use of corticosteroids 1. Overall, the management of patients taking oral diclofenac requires careful consideration of the potential risks and benefits, as well as strategies to minimize adverse effects.

From the FDA Drug Label

In patients taking diclofenac potassium tablets or other NSAIDs, the most frequently reported adverse experiences occurring in approximately 1%-10% of patients are: Gastrointestinal experiences including abdominal pain, constipation, diarrhea, dyspepsia, flatulence, gross bleeding/perforation, heartburn, nausea, GI ulcers (gastric/duodenal) and vomiting Abnormal renal function, anemia, dizziness, edema, elevated liver enzymes, headaches, increased bleeding time, pruritus, rashes and tinnitus reactions, appetite changes, death Cardiovascular System: arrhythmia, hypotension, myocardial infarction, palpitations, vasculitis Digestive System: colitis eructation, fulminant hepatitis with and without jaundice, liver failure, liver necrosis, pancreatitis Hemic and Lymphatic System: agranulocytosis, hemolytic anemia, aplastic anemia, lymphadenopathy, pancytopenia Metabolic and Nutritional: hyperglycemia Nervous System: convulsions, coma, hallucinations, meningitis Respiratory System: respiratory depression, pneumonia Skin and Appendages: angioedema, toxic epidermal necrolysis, erythema multiforme, exfoliative dermatitis, Stevens Johnson Syndrome, urticaria Special Senses: conjunctivitis, hearing impairment

The most common side effects of oral diclofenac are:

• Gastrointestinal experiences: abdominal pain, constipation, diarrhea, dyspepsia, flatulence, gross bleeding/perforation, heartburn, nausea, GI ulcers (gastric/duodenal) and vomiting
• Abnormal renal function, anemia, dizziness, edema, elevated liver enzymes, headaches, increased bleeding time, pruritus, rashes and tinnitus reactions, appetite changes 2

From the Research

Common Side Effects of Oral Diclofenac

The most common side effects of oral diclofenac, a Non-Steroidal Anti-Inflammatory Drug (NSAID), include:

• Gastrointestinal issues, such as gastritis and peptic ulceration 3, 4
• Central nervous system reactions, although fewer than those caused by indomethacin 3
• Depression of renal function 4
• Blood dyscrasias, erythema multiforme, hepatitis, and others, such as aseptic meningitis, anaphylaxis, and urticaria, although these are rare 4
• Headache, epigastric pain, nausea, and local pruritus 5

Comparison with Other NSAIDs

Oral diclofenac has been compared to other NSAIDs in terms of side effects:

• Diclofenac has a lower incidence of gastrointestinal side effects compared to some other NSAIDs, such as piroxicam and sulindac 4
• Diclofenac has a similar side effect profile to celecoxib, a COX-2 inhibitor, but with a higher frequency of upper gastrointestinal ulceration and gastrointestinal adverse events 6

Oral vs. Topical Diclofenac

The side effects of oral diclofenac have also been compared to those of topical diclofenac:

• Topical diclofenac has a better tolerability profile than oral diclofenac, with fewer gastrointestinal side effects 7
• Topical diclofenac may be a reasonable alternative for patients with a history of potential risk and adverse side effects 7