What is diclofenac gel?
Diclofenac gel is a nonsteroidal anti-inflammatory drug (NSAID) applied directly to the skin to treat pain and inflammation. As a topical medication, it delivers the active ingredient, diclofenac sodium, directly to the affected area, allowing it to penetrate through the skin to the underlying tissues and joints where the pain is originating. This localized delivery minimizes the amount of medication absorbed into the bloodstream, which often results in fewer systemic side effects compared to oral NSAIDs. Depending on the concentration and the intended use, diclofenac gel can be available over-the-counter (OTC) or by prescription. The OTC version (1%) is primarily marketed for arthritis pain, while a higher-strength prescription version (3%) has other specific applications, such as treating skin issues.
Mechanism of action
The anti-inflammatory and pain-relieving effects of diclofenac gel stem from its ability to inhibit specific enzymes in the body. It works by blocking cyclooxygenase (COX) enzymes, which play a key role in the production of prostaglandins—the chemicals responsible for triggering pain, swelling, and inflammation.
- Targeted action: The topical application allows diclofenac to accumulate in the underlying tissues, such as the synovium (the membrane lining joints). This provides a higher concentration of the drug directly at the site of inflammation while maintaining very low levels in the rest of the body.
- Pain signal reduction: By blocking prostaglandin synthesis, diclofenac reduces the sensitization of nerve endings to painful stimuli, which helps to ease joint stiffness and discomfort.
- Sustained effect: Some formulations, known as emulgels, are designed to release the diclofenac gradually into the skin over time, which provides a long-lasting analgesic effect.
Primary uses for diclofenac gel
Diclofenac gel has several specific uses, with the most common being the management of pain associated with osteoarthritis and the treatment of a certain skin condition.
Arthritis pain
Over-the-counter diclofenac sodium topical gel (1%), sold under brand names like Voltaren Arthritis Pain, is approved for the temporary relief of arthritis pain. It is particularly effective for joints located close to the skin's surface, such as the hands, wrists, elbows, feet, ankles, and knees. The topical application provides targeted relief for the aching joints and also helps reduce inflammation and stiffness. Many individuals prefer this option as it provides comparable efficacy to oral NSAIDs for hand and knee osteoarthritis but with a significantly lower risk of systemic side effects. The product is not intended for the treatment of sprains, strains, or bruises.
Actinic keratosis
A prescription-strength diclofenac gel (3%) is used for the topical treatment of actinic keratosis (AK). AK is a common skin condition characterized by scaly, crusty spots that develop on areas frequently exposed to the sun. The gel is applied to the lesion areas over a prescribed period, and the healing process may continue for a time after treatment ends. Its mechanism in treating AK is not fully understood, but it may involve blocking the growth of new blood vessels needed by the affected tissue.
How to apply diclofenac gel
For safe and effective use, it is crucial to follow the application instructions provided with the product or by a healthcare professional. OTC diclofenac gels for arthritis typically come with specific instructions to help measure the correct amount for each application.
- Preparation: Wash and dry the skin on the affected area before application. Do not apply the gel to skin that is broken, infected, or has a rash.
- Measure the dose: Use the provided measuring guide to apply the amount recommended for the specific body area being treated.
- Application: Gently rub the measured dose into the affected area. The frequency of application should be as directed.
- Aftercare: Wash your hands thoroughly after applying the gel, unless the treated area is your hands. In that case, follow instructions on when to wash them. Avoid showering or bathing for a specified time after application.
- Restrictions: Do not apply the gel to more body areas than instructed. Avoid covering the treated area with bandages, tight clothing, or heat. It may take some time to feel the full pain-relieving effect.
Diclofenac gel vs. oral NSAIDs
The choice between a topical and oral NSAID depends on the condition being treated, the location of the pain, and individual health factors. The primary difference lies in systemic absorption and the risk of side effects.
Comparison of topical diclofenac gel and oral NSAIDs
| Feature | Topical Diclofenac Gel | Oral NSAIDs |
|---|---|---|
| Systemic Absorption | Very limited; delivered directly to the site of pain, minimizing the amount in the bloodstream. | High; absorbed into the bloodstream and circulated throughout the body. |
| Systemic Side Effects | Low risk; fewer gastrointestinal, cardiovascular, and renal side effects compared to oral versions. | Higher risk; increased potential for side effects like stomach bleeding, ulcers, and cardiovascular events, especially with long-term use. |
| Local Side Effects | More common; can include application site reactions like dryness, itching, and rash. | Rare; local side effects are not a concern since the medication is taken by mouth. |
| Targeted Relief | Highly targeted; concentrates the drug in the specific area where it is applied. | Not targeted; distributes the drug systemically, affecting the entire body. |
| Ideal for | Localized pain from conditions like osteoarthritis of the hands, knees, ankles, and feet. | Generalized pain or pain that is not localized to a specific, superficial joint. |
| Risks | Minimal systemic risks, but caution is still advised for people with certain health conditions. | Significant systemic risks, especially for those with a history of GI issues or heart disease. |
Potential side effects and precautions
While diclofenac gel generally has fewer side effects than oral NSAIDs, it is not without risk. It is crucial to be aware of potential issues and discuss concerns with a healthcare provider.
Common side effects
Most side effects are confined to the application site and are typically mild to moderate in severity:
- Dermatitis: Redness, itching, and dryness of the skin at the application site.
- Irritation: A burning sensation or rash.
- Acne: The gel can sometimes cause or worsen acne.
Serious side effects
Though rare with topical application, systemic side effects can occur, particularly with higher doses, long-term use, or in individuals with pre-existing health conditions. Serious risks associated with NSAIDs include:
- Cardiovascular events: Increased risk of heart attack or stroke, especially in those with heart disease or who use the medication for a prolonged period.
- Gastrointestinal issues: Stomach bleeding, ulcers, or perforation of the stomach or intestines.
- Kidney damage: Reduced blood flow to the kidneys, which can be a concern for those with kidney disease.
Precautions
Certain individuals should exercise caution or avoid diclofenac gel. It is important to consult a healthcare provider if:
- You have had an allergic reaction to aspirin or other NSAIDs in the past.
- You are pregnant or breastfeeding, particularly in the later stages of pregnancy, as it can harm the fetus.
- You have pre-existing health conditions such as heart disease, high blood pressure, asthma, kidney disease, or liver disease.
- You are taking blood thinners or other medications that could interact with diclofenac.
- You are exposed to sunlight or UV radiation, as diclofenac can increase skin's sensitivity to light.
Conclusion
Diclofenac gel is an effective topical treatment that provides targeted relief for pain and inflammation associated with osteoarthritis, particularly in accessible joints like the hands and knees. It is also a treatment option for the precancerous skin condition, actinic keratosis. By delivering the active NSAID directly to the site of pain, it offers a favorable safety profile compared to oral NSAIDs, with a lower risk of systemic side effects. However, users must follow application guidelines carefully and be aware of potential side effects, especially if they have underlying health issues. Consulting a doctor or pharmacist is essential to ensure this medication is the right choice for an individual's specific needs.
