Is it safe to use diclofenac spray? A Comprehensive Safety Guide

October 8, 2025 •

4 min read

In 2021, an estimated 20.9% of U.S. adults experienced chronic pain. For many, topical medications are a key part of management. This raises a common question: is it safe to use diclofenac spray for localized pain relief, such as from arthritis?

Quick Summary

Diclofenac spray offers targeted pain relief but carries significant risks. It has an FDA black box warning for cardiovascular and gastrointestinal events. Safety depends on proper use, dosage, and consideration of individual health factors and contraindications.

Key Points

Black Box Warning: Diclofenac spray has an FDA black box warning for increased risk of serious cardiovascular events (heart attack, stroke) and gastrointestinal bleeding.
Localized Treatment: It's a topical NSAID designed for localized pain, primarily osteoarthritis of the knee, resulting in lower systemic drug exposure than oral pills.
Contraindications are Critical: It should not be used before/after heart bypass surgery or by individuals with an allergy to aspirin or other NSAIDs.
Application Matters: Safe use requires applying the medication to clean, dry, intact skin and following specific instructions regarding application area and post-application care.
Side Effects: The most common side effects are application site reactions like dry skin and rash, but serious systemic effects are still possible.
Pregnancy Warning: Avoid use at or after 20 weeks of pregnancy due to potential harm to the fetus.
Consult a Doctor: Its safety is individual-dependent; always consult a healthcare provider to weigh the benefits against the risks for your health condition.

What is Diclofenac Spray and How Does It Work?

Diclofenac is a nonsteroidal anti-inflammatory drug (NSAID) that reduces pain and inflammation. It works by inhibiting cyclooxygenase (COX) enzymes, which stops the body from producing substances called prostaglandins that cause pain and swelling. When applied as a topical spray (e.g., Pennsaid), it delivers the medication directly to the affected area, such as the knee, for conditions like osteoarthritis. This localized approach provides pain relief with lower systemic absorption compared to oral diclofenac, meaning less of the drug circulates throughout the body.

Proper Application for Maximum Safety

Correct application is crucial to minimize risks and maximize effectiveness. Always use diclofenac spray exactly as directed by a healthcare provider.

Prepare the Area: Apply the spray to clean, dry, and intact skin. Do not apply it to open wounds, infections, rashes, or damaged skin.
Administer the Dose: The application method and quantity used depend on the specific product and the area being treated. It is essential to follow the precise instructions from your healthcare provider or the product labeling.
Post-Application Care: Wash your hands thoroughly after application, unless you are treating your hands. Allow the area to dry completely before covering it with clothing. Avoid showering, bathing, or applying heat (like a heating pad) for a specific duration after application, as advised by your doctor or the product instructions. Also, avoid applying other topical products like sunscreens or lotions to the treated area unless approved by your doctor.

The FDA Black Box Warning: A Critical Consideration

Like all NSAIDs, diclofenac carries a black box warning from the FDA, the most serious warning possible. This highlights two major risks, even with topical use:

Serious Cardiovascular Thrombotic Events: NSAIDs increase the risk of serious and potentially fatal cardiovascular events, including heart attack and stroke. This risk can occur early in treatment and may increase with longer use and higher doses. People with existing heart disease or risk factors are at greater risk.
Serious Gastrointestinal (GI) Bleeding, Ulceration, and Perforation: NSAIDs can cause severe stomach and intestinal issues like bleeding, ulcers, and holes, which can be fatal. These events can happen at any time without warning symptoms, and the risk is higher in older adults and those with a history of GI ulcers or bleeding.

Potential Side Effects

While topical application reduces systemic exposure, side effects can still occur.

Common Local Side Effects

Application site reactions are the most common issues:

Dry skin, redness, itching, or rash
Scaling, swelling, or irritation
Contact dermatitis

Potential Systemic Side Effects

Though less common than with oral forms, systemic side effects are possible:

Headache, dizziness
Stomach pain, constipation, diarrhea, heartburn
Increased blood pressure
Fluid retention (edema)

Serious systemic side effects requiring immediate medical attention include signs of a heart attack (chest pain, shortness of breath), stroke (weakness on one side of the body, slurred speech), or GI bleeding (black stools, vomiting blood).

Who Should Avoid Diclofenac Spray? (Contraindications)

Diclofenac spray is not safe for everyone. You should not use it if you:

Are in the period just before or after coronary artery bypass graft (CABG) surgery.
Have had an allergic reaction, asthma, or hives after taking aspirin or another NSAID.
Have a known hypersensitivity to diclofenac or any of its ingredients.
Plan to apply it to damaged or broken skin.

Use with caution is advised for individuals with a history of heart disease, high blood pressure, stomach ulcers, kidney or liver disease, or who are pregnant or breastfeeding. It is especially important to avoid NSAIDs like diclofenac around or after 20 weeks of pregnancy, as it can harm the fetus.

Comparison: Diclofenac Spray vs. Gel vs. Oral Tablets


Feature	Diclofenac Spray/Solution	Diclofenac Gel	Oral Diclofenac Tablets
Application	Sprayed or pumped onto skin, spreads evenly.	Squeezed from a tube and rubbed into skin, often with a dosing card.	Swallowed as a pill.
Systemic Absorption	Low; 5- to 17-fold lower systemic exposure than oral forms.	Low; absorption is minimal compared to oral tablets.	High; the drug circulates throughout the entire body.
Primary Side Effects	Local skin reactions like dryness and dermatitis are most common.	Local skin reactions like itching and rash are common.	Gastrointestinal issues (dyspepsia, diarrhea) are significantly more common.
Risk Profile	Lower risk of systemic GI and cardiovascular events compared to oral tablets, but the risk is still present.	Similar to spray; lower systemic risk than oral tablets, but FDA black box warning still applies.	Highest risk of systemic cardiovascular and GI side effects.
Best For	Localized pain, especially in the knees, where it is specifically indicated.	Localized pain in joints amenable to topical treatment like hands, wrists, elbows, knees, ankles, or feet.	Widespread or severe pain; conditions where topical treatment is not practical.

Conclusion

So, is it safe to use diclofenac spray? The answer is conditional. For the right person, it can be a safer alternative to oral NSAIDs for managing localized osteoarthritis pain because it minimizes systemic exposure. However, it is not without significant risks. The FDA's black box warning for cardiovascular and gastrointestinal events applies to all forms of diclofenac, including the spray. Its safety profile depends heavily on adhering to proper usage instructions, avoiding contraindications, and being aware of potential side effects. Always consult with a healthcare professional to determine if diclofenac spray is an appropriate and safe choice for your specific health situation.

Disclaimer: This article is for informational purposes only and does not constitute medical advice. Always consult with a qualified healthcare professional before starting or changing any medication.

Authoritative Link: FDA Medication Guide for NSAIDs

Frequently Asked Questions

Diclofenac spray should be used for the shortest duration possible at the lowest effective application frequency and amount. It is not intended for long-term use without a doctor's supervision due to the increased risk of cardiovascular and GI side effects with prolonged use.

Using more than the prescribed amount can increase your risk of both local skin reactions and serious systemic side effects, including stomach ulcers, bleeding, heart attack, or stroke. Do not apply more than directed by your healthcare provider.

You should not use diclofenac spray with oral NSAIDs (like ibuprofen, naproxen, or oral diclofenac) or aspirin unless specifically directed by your doctor, as this increases the risk of side effects.

NSAIDs, including topical diclofenac, can cause new or worsening high blood pressure. Your blood pressure should be monitored while using this medication. Discuss this with your doctor, as you may be at higher risk for side effects.

Yes, you should avoid exposing the treated area to natural or artificial sunlight. Diclofenac can make your skin more sensitive to sunlight (photosensitivity), increasing the risk of a severe sunburn reaction.

Topical diclofenac generally has a lower risk of systemic side effects, particularly gastrointestinal issues, compared to oral diclofenac because less of the drug is absorbed into the bloodstream. However, the serious risks of heart and stomach problems still exist.

You should not use it right before or after heart bypass surgery (CABG) or if you've had asthma, hives, or an allergic reaction to aspirin or other NSAIDs. It's also contraindicated for use on damaged or broken skin.