Diclofenac: Uses, dosage, side effects, warnings & patient reviews

What is Diclofenac?

Diclofenac is a nonsteroidal anti-inflammatory drug (NSAID) used to treat pain and inflammatory conditions. It is available in several forms, including oral tablets (e.g., diclofenac sodium and diclofenac potassium), topical gel, patches, and solution for injection.

As a member of the NSAID class, diclofenac works by inhibiting enzymes called cyclooxygenases (COX-1 and COX-2), which reduces the body’s production of prostaglandins, chemicals that promote pain, fever, and inflammation. Among NSAIDs, diclofenac is considered one of the most potent for pain relief but is also associated with a higher risk of cardiovascular side effects compared to some others.

It is crucial to use the lowest effective dose for the shortest duration necessary to control symptoms.

How to Take Diclofenac

Proper use of diclofenac is essential for maximizing benefits and minimizing risks. Always follow your healthcare provider’s instructions and the directions on the label.

Administration Guidelines

Oral Tablets (Diclofenac Sodium/Potassium): Swallow the tablet whole with a full glass of water. To reduce the risk of stomach upset and ulceration, always take it with food or milk. Do not crush, chew, or break delayed-release or extended-release tablets.

Topical Gel (e.g., Voltaren Gel): Apply a thin layer to clean, dry skin over the affected area. Do not apply to broken or infected skin. Wash your hands immediately after application unless your hands are the treated area. Do not cover with bandages or apply heat.

Timing and Duration

Dosage frequency depends on the formulation and condition being treated. For example, immediate-release tablets for pain may be taken 2-3 times daily, while extended-release tablets are typically taken once daily. Do not take more than the prescribed amount or use it longer than directed, especially without medical supervision.

Important Precautions

• Do not combine different oral NSAID products (e.g., ibuprofen, naproxen) unless directed by your doctor.
• Stay well-hydrated while taking diclofenac to support kidney function.
• Stop taking diclofenac and contact your doctor immediately if you develop signs of stomach bleeding (e.g., black/tarry stools, vomiting blood or coffee-ground material) or allergic reaction.

Side Effects of Diclofenac

Diclofenac, like all NSAIDs, can cause a range of side effects. Patients should understand their medication information to recognize common and serious reactions.

What is Diclofenac Used For?

Diclofenac is used to reduce inflammation and relieve pain from various acute and chronic conditions.

Primary Medical Uses

• Osteoarthritis and Rheumatoid Arthritis: Reduces joint pain, swelling, and stiffness. It is often part of a management plan that may include other medications, as discussed in our guide to DMARDs for arthritis.
• Ankylosing Spondylitis: Manages pain and inflammation in the spine.
• Acute Gout: Helps control pain and inflammation during a gout attack.
• Acute Musculoskeletal Pain: Such as sprains, strains, and back pain.
• Migraine: Diclofenac potassium in a soluble formulation can be used for the acute treatment of migraine attacks.
• Topical Pain Relief: Diclofenac gel (e.g., Voltaren Gel) is applied directly to joints affected by osteoarthritis, such as knees and hands, providing targeted relief with lower systemic absorption.

Important Limitations

Diclofenac treats symptoms (pain and inflammation) but does not cure the underlying disease or stop disease progression in conditions like rheumatoid arthritis. It is not appropriate for all types of pain; for example, it is not typically a first-choice drug for post-surgical dental pain.

Important Safety Concerns and Considerations

Cardiovascular Risk

Diclofenac carries a boxed warning (the most serious FDA warning) regarding an increased risk of serious and sometimes fatal cardiovascular events, including heart attack and stroke. This risk may increase with duration of use and is higher in people with pre-existing heart disease or risk factors. The risk exists even for short-term use. Diclofenac is contraindicated for treating pain before or after coronary artery bypass graft (CABG) surgery.

Gastrointestinal Risk

NSAIDs like diclofenac pose a significant risk of serious gastrointestinal (GI) adverse events, including bleeding, ulceration, and perforation of the stomach or intestines, which can be fatal. These events can occur at any time during use, without warning symptoms, and are more likely in the elderly, those on higher doses, and those with a history of ulcers or GI bleeding.

Kidney Toxicity

Long-term use of diclofenac can lead to kidney injury, including acute renal failure. The risk is higher in people with pre-existing kidney disease, heart failure, liver cirrhosis, in the elderly, and in those taking diuretics or ACE inhibitors. Kidney function should be monitored with prolonged use.

Liver Toxicity

Severe liver reactions, including fatal hepatitis, have been reported with diclofenac use. Patients should be monitored for symptoms such as fatigue, nausea, jaundice, and right upper quadrant pain. Diclofenac should be discontinued at the first sign of liver dysfunction.

Topical vs. Oral Use

Diclofenac gel is associated with significantly lower systemic absorption and therefore a lower risk of serious GI, cardiovascular, and kidney side effects compared to oral forms. It is a preferred option for localized pain (e.g., osteoarthritis of hands or knees) when possible.

Critical Warnings for Diclofenac Use

Cardiovascular Thrombotic Events

NSAIDs, including diclofenac, increase the risk of myocardial infarction, stroke, and other thrombotic events. This risk can occur within the first weeks of use and increases with higher doses and longer duration. Patients with cardiovascular disease or risk factors for it should use diclofenac with extreme caution and only after discussing risks and benefits with their doctor.

Gastrointestinal Bleeding, Ulceration, and Perforation

The risk of GI events is higher with diclofenac than with many other NSAIDs. To minimize risk, use the lowest effective dose for the shortest possible time. Be vigilant for signs of ulceration and bleeding, even in the absence of previous GI symptoms. Concomitant use of aspirin, other NSAIDs, corticosteroids, or alcohol increases this risk substantially.

Hepatotoxicity

Elevations in liver function tests may occur in up to 15% of patients. In rare cases, these can progress to severe hepatic injury. Diclofenac should be discontinued if abnormal liver tests persist or worsen, or if clinical signs of liver disease develop.

Hypertension

Diclofenac can impair the activity of blood pressure medications (e.g., ACE inhibitors, ARBs, diuretics) and cause new-onset hypertension or worsen pre-existing hypertension. Blood pressure should be monitored closely during treatment, especially in those with pre-existing hypertension.

Heart Failure and Edema

Fluid retention and edema have been observed in patients taking diclofenac. It should be used with great caution in patients with pre-existing heart failure, as NSAIDs may increase the risk of hospitalization due to heart failure exacerbation.

Diclofenac Dosage Information

Diclofenac dosage varies widely based on the formulation, condition treated, and patient factors. The following are general guidelines; always use the lowest effective dose for the shortest duration needed.

Important Administration Notes

• Renal Impairment: Not recommended in patients with advanced kidney disease. Use with caution and at a reduced dose in mild-to-moderate impairment.
• Hepatic Impairment: Dose reduction is recommended. Not recommended in severe liver impairment.
• Elderly: Start at the low end of the dosing range due to increased risk of adverse events.
• Missed Dose: If on a scheduled regimen, take as soon as remembered. If close to the next dose, skip it. Do not double dose.

Drug Interactions with Diclofenac

Diclofenac has numerous potentially significant drug interactions. This table lists key examples; it is not exhaustive. Always inform your healthcare providers of all medications you take.

Additional Information

Cost and Generic Availability

Diclofenac is widely available as a generic medication, making it an affordable option. Brand-name products like Voltaren (gel and tablets) are typically more expensive. Prices can vary by pharmacy and insurance coverage.

Alternative Pain Management

Medication is one part of pain management. Other strategies include physical therapy, exercise, weight management, and other medications. For a broader perspective, explore our guide on navigating pain relief options.

Reporting Side Effects

Report any adverse reactions or side effects to your healthcare provider. You can also report them directly to the relevant national health authority (e.g., the FDA MedWatch program in the United States). This helps improve overall drug safety.

References and Medical Sources

The information on this page is based on authoritative medical sources and prescribing information.

1. U.S. Food and Drug Administration (FDA). Voltaren (diclofenac sodium) Prescribing Information. [Revised 2022]. https://www.accessdata.fda.gov/drugsatfda_docs/label/2011/019201s039s040lbl.pdf
2. MedlinePlus. Diclofenac. U.S. National Library of Medicine; [Updated 2022]. https://medlineplus.gov/druginfo/meds/a689002.html
3. American College of Rheumatology. Guidelines for the Management of Osteoarthritis of the Hand, Hip, and Knee (2019).
4. Drugs.com. Diclofenac Professional Monograph. Drugs.com; [Updated 2024]. https://www.drugs.com/monograph/diclofenac.html
5. Schmidt, M., et al. “Diclofenac use and cardiovascular risks: series of nationwide cohort studies.” BMJ (2018).

Disclaimer: The information on this site is provided for informational purposes only and is not medical advice. It does not replace professional medical consultation, diagnosis, or treatment. Do not self-medicate based on the information presented on this site. Always consult with a doctor or other qualified healthcare professional before making any decisions about your health.