What Is Diclofenac Gel and How Does It Work?
Diclofenac gel is a topical nonsteroidal anti-inflammatory drug (NSAID) available both over-the-counter and by prescription, commonly known by brand names like Voltaren Arthritis Pain. Unlike oral NSAIDs that circulate throughout the body, the gel is applied directly to the skin over a painful joint. The active ingredient, diclofenac sodium, then penetrates the skin and accumulates in the underlying tissues, such as the synovial fluid and joint capsules, where it exerts its anti-inflammatory effects.
The primary mechanism of action for diclofenac, like other NSAIDs, involves inhibiting cyclooxygenase (COX) enzymes, particularly COX-2. These enzymes are responsible for producing prostaglandins, hormone-like substances that cause pain and inflammation in the body. By blocking the production of prostaglandins at the site of injury or inflammation, diclofenac gel reduces pain, swelling, and stiffness. The key difference is that this action is highly concentrated at the application site, resulting in significantly lower systemic drug absorption.
Primary Uses of Diclofenac Gel
Diclofenac gel is primarily used for the treatment of pain associated with inflammatory conditions in specific joints. Its targeted delivery makes it highly effective for localized issues while avoiding or reducing the systemic side effects often associated with oral NSAIDs.
1. Osteoarthritis Pain This is the most common use for diclofenac gel. It is an effective treatment for the pain, stiffness, and swelling related to osteoarthritis in peripheral joints. Common areas of application include:
- Knees: Applying the gel to the knees can help manage the pain and stiffness that can make walking difficult.
- Hands and Wrists: People with arthritis in their hands or wrists can use the gel to improve grip strength and reduce morning stiffness.
- Feet and Ankles: Applying the gel to these areas can alleviate pain and make daily activities more comfortable.
2. Actinic Keratosis In a higher 3% concentration, diclofenac gel is available by prescription (previously under the brand name Solaraze) to treat actinic keratosis. This is a skin condition characterized by flat, scaly growths caused by sun exposure that can potentially become cancerous if left untreated. The gel works by stopping the growth of abnormal skin cells.
3. Acute Pain from Soft Tissue Injuries While not FDA-approved for sprains or strains in the same over-the-counter formulation, other topical diclofenac products (like patches or solutions) can be prescribed for acute pain caused by minor sprains, strains, and contusions. The local anti-inflammatory effect helps reduce swelling and pain from these common injuries.
Advantages Over Oral NSAIDs
Using diclofenac gel instead of an oral NSAID offers several distinct advantages, particularly for individuals at a higher risk of systemic side effects.
- Minimized Systemic Absorption: The gel delivers the active ingredient directly to the affected area, resulting in much lower concentrations of the drug in the bloodstream compared to taking a pill. This reduces the risk of serious gastrointestinal, cardiovascular, and kidney-related side effects.
- Targeted Relief: Because the medication is concentrated at the site of pain and inflammation, it provides effective local relief exactly where it is needed.
- Guideline-Supported First-Line Therapy: Medical guidelines often recommend topical NSAIDs for treating osteoarthritis pain, especially in older patients or those with existing health conditions, due to their favorable safety profile.
- Avoids Swallowing Pills: For patients who have difficulty swallowing pills or prefer not to take oral medication, the gel provides a convenient and effective alternative.
How to Apply Diclofenac Gel Correctly
To ensure maximum effectiveness and safety, it is crucial to apply diclofenac gel as directed. Dosing cards are often included with the product to help measure the correct amount for different body parts.
- Clean and Dry the Area: Wash and dry the skin of the affected joint before application.
- Measure the Dose: Use the enclosed dosing card to measure the correct amount of gel for the specific joint. The dose for an upper-body area (e.g., hand, wrist) is typically less than for a lower-body area (e.g., knee, foot).
- Rub in Gently: Gently massage the gel into the skin over the entire affected area until it is fully absorbed.
- Wait Before Covering: Do not cover the treated area with a bandage or clothes for at least 10 minutes to allow the gel to dry and absorb fully.
- Wash Hands: Wash your hands thoroughly after applying the gel unless the hands are the area being treated. If treating hands, wait at least one hour before washing them.
- Avoid Water: Do not shower or bathe for at least one hour after application to avoid washing the medication away.
Diclofenac Gel vs. Oral NSAIDs: A Comparison
To highlight the differences in application and side effect profiles, here is a comparison between diclofenac gel and oral NSAIDs.
| Feature | Diclofenac Gel | Oral NSAIDs (e.g., Ibuprofen, Naproxen) |
|---|---|---|
| Administration | Applied topically to the skin | Taken by mouth in pill or capsule form |
| Absorption | Localized absorption through the skin into underlying tissues | Absorbed into the bloodstream via the digestive tract |
| Systemic Risk | Significantly lower risk of gastrointestinal, cardiovascular, and kidney side effects | Higher risk of serious systemic side effects, especially with long-term use |
| Common Side Effects | Localized skin reactions at the application site (e.g., dryness, itching, rash) | Gastrointestinal issues (e.g., upset stomach, heartburn, bleeding), cardiovascular events, high blood pressure |
| Best For | Localized joint pain from arthritis in hands, wrists, elbows, knees, ankles, and feet | Generalized pain, headaches, fever, and pain in joints that are not easily accessible for topical application |
Potential Side Effects of Diclofenac Gel
While diclofenac gel has a more favorable safety profile than oral NSAIDs, side effects can still occur. The most common side effects are localized skin reactions at the application site, which may include dryness, redness, itching, or irritation.
More serious, though rare, side effects can occur due to low systemic absorption. Patients should be aware of the following potential risks:
- Serious Skin Reactions: Blistering, peeling skin, or other severe rashes can occur.
- Cardiovascular Events: Increased risk of heart attack, heart failure, and stroke, especially with prolonged use. This risk is still significantly lower than with oral NSAIDs but remains a possibility.
- Gastrointestinal Bleeding: While less common than with oral forms, stomach bleeding can occur, particularly in older patients or those with a history of ulcers.
- Photosensitivity: The gel can make skin more sensitive to sunlight, so sun exposure should be limited on the treated area.
Patients with a history of allergies to aspirin or other NSAIDs should avoid diclofenac gel. If any serious or bothersome side effects occur, discontinue use and consult a doctor.
Conclusion
Diclofenac gel is an effective and safe option for providing targeted pain relief for localized conditions, primarily osteoarthritis in specific joints. Its mechanism of delivering anti-inflammatory medication directly to the site of pain minimizes the systemic side effect risks associated with oral NSAIDs. For many patients, especially those at higher risk for gastrointestinal or cardiovascular complications, the gel provides an excellent, guideline-supported alternative. Always follow application instructions carefully and consult a healthcare provider to ensure it is the right treatment option for your condition.
For more detailed information on topical diclofenac and its uses, you can visit the MedlinePlus drug information page.
