Diclofenac is a nonsteroidal anti-inflammatory drug (NSAID) used to manage mild to moderate pain and conditions like arthritis. The sustained-release (SR) formulation, also known as extended-release (ER), is designed to provide long-lasting relief with a once-daily or twice-daily dose. While effective, like all medications, it carries a risk of potential side effects, which range from common and manageable to serious and life-threatening. The FDA places boxed warnings on diclofenac and other NSAIDs due to the potential for serious cardiovascular and gastrointestinal events.
Common Side Effects of Diclofenac SR
Many individuals experience only mild side effects when taking diclofenac SR. These are often temporary and may subside as your body adjusts to the medication.
Gastrointestinal (GI) Effects
These are among the most frequent side effects associated with oral NSAIDs and can often be mitigated by taking the medication with food.
- Nausea and/or vomiting
- Diarrhea or constipation
- Abdominal pain or discomfort
- Indigestion, gas, or heartburn
Neurological and Sensory Effects
- Headache: Although diclofenac is sometimes used for headaches, it can also cause them as a side effect.
- Dizziness or Drowsiness: These can affect daily activities, such as driving or operating machinery.
- Tinnitus: A sensation of ringing in the ears is a known side effect of NSAIDs.
Other Common Effects
- Edema: Fluid retention leading to swelling, particularly in the ankles, feet, or lower legs, is common.
- Skin Reactions: Mild skin rashes and itching can occur.
Serious Adverse Effects
The risk of serious side effects with diclofenac SR is higher with long-term use and higher doses, and in patients with pre-existing conditions. Immediate medical attention is required for any signs of these serious complications.
Cardiovascular Risks
The FDA has issued a boxed warning for all NSAIDs (except aspirin) regarding an increased risk of serious cardiovascular events, including heart attack and stroke, which can be fatal. The risk is particularly high for people with heart disease and those taking higher doses or using it long-term. Diclofenac is contraindicated for pain management right before or after coronary artery bypass graft (CABG) surgery. NSAIDs can also cause or worsen high blood pressure and contribute to congestive heart failure.
Gastrointestinal Complications
Another boxed warning highlights the risk of serious GI adverse events, including bleeding, ulcers, and perforation of the stomach or intestines. These can occur without warning and are more likely in the elderly or those with a history of GI problems.
Renal and Hepatic Toxicity
Diclofenac can affect kidney and liver function. Long-term use can lead to kidney damage and, in rare cases, liver failure. Symptoms of liver issues include jaundice (yellowing skin/eyes), dark urine, and abdominal pain.
Severe Skin Reactions
Although rare, life-threatening skin reactions like Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) have been reported with diclofenac. These typically involve a severe rash, fever, and blistering.
Allergic Reactions
Serious allergic reactions, such as anaphylaxis, can occur, even in those without a known hypersensitivity to diclofenac. Symptoms include difficulty breathing, swelling of the face or throat, and hives.
Hematologic Issues
Diclofenac can cause anemia (low red blood cell count) and may increase the risk of bleeding, especially when combined with blood thinners.
Management and Prevention of Side Effects
To minimize the risk of diclofenac SR side effects, healthcare providers recommend several strategies:
- Lowest effective dose: Take the lowest possible dose that controls your symptoms for the shortest duration necessary.
- Take with food: Consuming diclofenac with food can help reduce common GI discomfort.
- Avoid alcohol: Alcohol use, especially in large amounts, increases the risk of GI bleeding.
- Monitor health conditions: If you have a history of heart, kidney, or liver disease, close monitoring by a doctor is essential.
- Report symptoms: Promptly report any concerning symptoms, especially signs of serious complications, to your healthcare provider.
Comparison of Mild vs. Serious Diclofenac SR Side Effects
| Aspect | Mild Side Effects | Serious Side Effects |
|---|---|---|
| Symptom Type | GI upset, headache, dizziness, mild rash | Cardiovascular events (heart attack, stroke), GI bleeding/ulcers, kidney/liver damage |
| Onset | Often temporary, may occur early in treatment | Can occur at any time, often without warning symptoms |
| Severity | Usually manageable and non-life-threatening | Potentially life-threatening, requires immediate medical care |
| Risk Factors | Often tied to individual sensitivity or dosage | Higher doses, long-term use, older age, history of GI or heart disease |
| Management | Taking with food, staying hydrated, rest | Medical evaluation, discontinuation of medication |
Conclusion
Diclofenac SR is an effective NSAID for managing pain and inflammation, but its use is associated with a range of side effects, from common digestive issues to severe and potentially fatal cardiovascular and gastrointestinal complications. Patients should be fully aware of both the common side effects and the serious risks, particularly those outlined in the boxed warnings. To minimize risk, always use the lowest effective dose for the shortest period, and consult a healthcare provider for any questions or concerning symptoms. If you have pre-existing health conditions, or are older, your risk of serious side effects may be higher, emphasizing the importance of a thorough discussion with your doctor before starting treatment.
This article provides general information and is not a substitute for professional medical advice. Always consult your healthcare provider regarding the specific risks and benefits of diclofenac SR or any other medication.
