Diclofenac

What Does Diclofenac Do?

Diclofenac is an anti-inflammatory drug. 

It’s known as a non-steroidal anti-inflammatory drug (NSAID), and is primarily used for its anti-inflammatory, analgesic, and antipyretic qualities (lowers body temperature in cases of fever). It's predominantly used to treat muscle and joint pains, but also menstrual cramps, migraines, and dental pain.

How Does Diclofenac Work? (the complicated stuff)

Diclofenac operates by obstructing the action of cyclooxygenase (COX) enzymes, which are instrumental in turning arachidonic acid into prostaglandins, integral molecules for inflammation, pain transmission and fever. By curtailing prostaglandin production, Diclofenac relieves inflammation, pain, and fever.

Drug Type and Category of Diclofenac

Diclofenac is classified as a non-steroidal anti-inflammatory drug (NSAID).

What dosage of Diclofenac should you be taking?

NICE Guidelines ¹

Osteoarthritis:

• Immediate-release tablets: 50 mg orally two or three times a day.
• Extended-release tablets: 100 mg orally once a day.
• Maximum daily dose: 150 mg.

Rheumatoid Arthritis:

• Immediate-release tablets: 50 mg orally three or four times a day.
• Extended-release tablets: 100 mg orally once a day; in some cases, up to 100 mg twice a day may be used, but this is rare and should be under close medical supervision.
• Maximum daily dose: 225 mg.

Ankylosing Spondylitis:

• Immediate-release tablets: 25 mg orally four times a day, with an additional 25 mg dose at bedtime if necessary.
• Maximum daily dose: 125 mg.

Acute Pain or Primary Dysmenorrhea:

• Immediate-release tablets: 50 mg orally three times a day. An initial dose of 100 mg may be administered, followed by 50 mg doses.
• Maximum daily dose: 150 mg.

Migraine:

• Oral solution (powder for solution): 50 mg taken once at the onset of migraine symptoms.
• Note: The safety and efficacy of a second dose have not been established.

Topical Gel (for Osteoarthritis):

• Upper extremities (e.g., hands, wrists, elbows): Apply 2 grams to the affected area four times a day.
• Lower extremities (e.g., knees, ankles, feet): Apply 4 grams to the affected area four times a day.
• Maximum total daily dose: 32 grams across all affected joints.

Important Considerations:

• Use the lowest effective dose for the shortest duration necessary to manage symptoms.
• Diclofenac carries risks of serious cardiovascular and gastrointestinal events; therefore, it should be used under medical supervision, especially in individuals with underlying health conditions.
• Dosage adjustments may be necessary for individuals with renal or hepatic impairments.
• Always consult with a healthcare professional before initiating or adjusting diclofenac therapy to ensure it is appropriate for your specific health circumstances.

These guidelines are general; individual dosing may vary based on specific health conditions and response to treatment. Always follow the advice of your healthcare provider.

What are the side-effects of Diclofenac?

Common Side Effects:

• Gastrointestinal:
• Stomach pain or discomfort
• Nausea and vomiting
• Diarrhea or constipation
• Indigestion or heartburn
• Central Nervous System:
• Headache
• Dizziness
• Drowsiness
• Skin:
• Rash or itching
• Photosensitivity (increased sensitivity to sunlight)

Less Common but Serious Side Effects:

• Cardiovascular:
• High blood pressure
• Increased risk of heart attack or stroke, especially with prolonged use or high doses
• Gastrointestinal:
• Ulcers or bleeding in the stomach or intestines (symptoms may include black stools, vomiting blood)
• Severe abdominal pain
• Kidney:
• Reduced kidney function, leading to fluid retention, swelling (edema), or increased creatinine levels
• Rare cases of kidney failure
• Liver:
• Elevated liver enzymes
• Rare cases of liver failure (symptoms may include jaundice, fatigue, dark urine)
• Respiratory:
• Shortness of breath
• Asthma exacerbation (especially in individuals sensitive to NSAIDs)
• Hematological:
• Anemia or low blood cell counts (symptoms may include fatigue, pallor, or unusual bleeding/bruising)

Rare and Severe Side Effects:

• Allergic Reactions:
• Anaphylaxis (life-threatening allergic reaction causing difficulty breathing or swelling of the face/throat)
• Stevens-Johnson syndrome or toxic epidermal necrolysis (severe skin reactions)
• Neurological:
• Seizures
• Confusion or mood changes

Topical Diclofenac Side Effects:

• Skin irritation at the application site (redness, itching, scaling)
• Allergic skin reactions

Important Notes:

• The risk of serious side effects is higher in older adults, people with pre-existing heart or gastrointestinal conditions, and those taking high doses or long-term diclofenac.

Interactions

Medications That May Increase the Risk of Side Effects:

1. Other NSAIDs or Aspirin:
• Increases the risk of gastrointestinal bleeding and ulcers.
2. Anticoagulants (e.g., Warfarin):
• Heightens the risk of bleeding.
3. Antiplatelet Drugs (e.g., Clopidogrel):
• Further increases bleeding risk.
4. Corticosteroids (e.g., Prednisone):
• Elevates the likelihood of stomach ulcers or bleeding.
5. Selective Serotonin Reuptake Inhibitors (SSRIs):
• Drugs like fluoxetine or sertraline may amplify the risk of gastrointestinal bleeding.

Medications That Affect Kidney Function:

1. Diuretics (e.g., Furosemide, Hydrochlorothiazide):
• Diclofenac may reduce their effectiveness and increase the risk of kidney problems.
2. ACE Inhibitors or ARBs (e.g., Lisinopril, Losartan):
• Combination with diclofenac can lead to worsening kidney function or hyperkalemia.
3. Cyclosporine and Tacrolimus:
• Increases the risk of nephrotoxicity.

Drugs Affecting Cardiovascular Function:

1. Beta-Blockers (e.g., Atenolol, Metoprolol):
• Diclofenac may reduce their blood-pressure-lowering effect.
2. Digoxin:
• Diclofenac can increase digoxin levels, leading to toxicity.

Other Significant Interactions:

1. Lithium:
• Diclofenac can increase lithium levels, leading to toxicity.
2. Methotrexate:
• May elevate methotrexate levels, increasing the risk of toxicity.
3. Antihyperglycemics (e.g., Insulin or Sulfonylureas):
• Diclofenac can either enhance or reduce blood sugar-lowering effects.
4. Alcohol:
• Increases the risk of stomach ulcers and gastrointestinal bleeding.

Natural Alternatives to Diclofenac

Several natural alternatives to diclofenac have been studied for their anti-inflammatory and analgesic properties. These options may help manage pain and inflammation with fewer side effects. Always consult a healthcare provider before starting any natural treatment, especially if you are already on medication.

1. Curcumin (Turmeric Extract)

Curcumin, the active compound in turmeric, has potent anti-inflammatory properties. Studies suggest it can inhibit inflammatory pathways like COX-2, similar to NSAIDs, without the gastrointestinal side effects ².

• Dosage: Typically, 500–2,000 mg per day of standardised curcumin extract.

2. Omega-3 Fatty Acids

Found in fish oil, omega-3 fatty acids (EPA and DHA) can reduce inflammation by modulating cytokine production and decreasing COX activity ³.

• Dosage: 1,000–3,000 mg of combined EPA and DHA daily.

3. Boswellia Serrata (Frankincense)

Boswellic acids, the active compounds in Boswellia, have demonstrated COX-2 inhibition and potential benefits for osteoarthritis and rheumatoid arthritis ⁴.

• Dosage: 100–300 mg of Boswellia extract, standardised to 30–60% boswellic acids, two to three times daily.

4. Ginger (Zingiber officinale)

Ginger contains compounds like gingerols and shogaols, which have anti-inflammatory effects. It may be particularly effective in managing osteoarthritis symptoms ⁵.

• Dosage: 500–1,000 mg of ginger extract daily.

5. Capsaicin (Chili Pepper Extract)

Capsaicin reduces pain by depleting substance P, a neurotransmitter involved in pain signaling ⁶. It is commonly used topically.

• Dosage: Apply a cream containing 0.025–0.075?psaicin to affected areas up to four times daily.

6. Willow Bark (Salix spp.)

Willow bark contains salicin, a natural precursor to aspirin. It has been used for centuries to reduce pain and inflammation ⁷.

• Dosage: 240 mg of salicin daily.

7. Green Tea (Camellia sinensis)

Rich in polyphenols, especially epigallocatechin gallate (EGCG), green tea has anti-inflammatory effects and may benefit conditions like arthritis ⁸.

• Dosage: 2–3 cups of green tea daily or 300–500 mg of standardised extract.

8. Devil’s Claw (Harpagophytum procumbens)

This herb is traditionally used for its analgesic and anti-inflammatory effects, particularly in arthritis ⁹.

• Dosage: 600–1,200 mg of standardised extract daily.

9. Bromelain (Pineapple Enzyme)

Bromelain, derived from pineapples, can reduce inflammation and pain in musculoskeletal disorders ¹⁰.

• Dosage: 500–1,000 mg of bromelain daily between meals.

Interesting facts about Diclofenac

Diclofenac, a once-widely used NSAID first introduced in the 1970s, is known for its effectiveness in relieving pain, reducing inflammation, and lowering fever. Its name derives from its chemical structure, dichloro-phenyl-acetic acid, which underpins its ability to block prostaglandin production. 

Diclofenac seems to have lost favour in the UK, and is rarely prescribed now by GPs. They prefer to prescribe Naproxen. This could be because Diclofenac shows issues with the cardiovascular system (increased risk of stroke and heart attack). It is comparable to Vioxx (Rofecoxib) that was withdrawn from the market due to similar concerns. Naproxen is generally considered to be safer. 

Available in various forms—oral tablets, topical gels, eye drops, and injectables—diclofenac is versatile, treating conditions from arthritis to postoperative pain. Despite its benefits, it carries notable cardiovascular risks, slightly higher than other NSAIDs, prompting recommendations for the lowest effective dose and shortest duration.

Interestingly, diclofenac has been linked to environmental concerns, particularly the decline of vulture populations in South Asia due to kidney failure caused by consuming treated livestock, leading to restrictions on its veterinary use. Surprisingly, it remains on the WHO Essential Medicines List, possibly due to it being cheap, and widely available in low-economic countries. 

Disclaimer

This article is generated for informational purposes only. It was created in January 2025. Medications and medical guidance can change over time. Therefore, it is essential to consult with your general practitioner or healthcare provider before making any decisions regarding medications or treatment plans. Your GP can provide personalised advice based on your specific health needs and conditions.

References

1. https://bnf.nice.org.uk/drugs/diclofenac-sodium/
2. Aggarwal BB, et al. (2013). "Curcumin: the Indian solid gold." Advances in Experimental Medicine and Biology.
3. Calder PC. (2017). "Omega-3 fatty acids and inflammatory processes." Nutrients.
4. Sengupta K, et al. (2011). "A double-blind, randomized, placebo-controlled study of Boswellia serrata extract for osteoarthritis." Arthritis Research & Therapy.
5. Zeng C, et al. (2015). "Efficacy and safety of ginger in osteoarthritis patients." Osteoarthritis and Cartilage.
6. Deal CL, et al. (1991). "Treatment of arthritis with capsaicin-containing topical preparations." The Clinical Journal of Pain.
7. Vlachojannis JE, et al. (2011). "The efficacy and safety of willow bark in the treatment of pain." Phytotherapy Research.
8. Yang CS, et al. (2016). "Mechanisms of body weight reduction by green tea polyphenols." Molecular Nutrition & Food Research.
9. Brendler T, et al. (2019). "Devil's claw as an anti-inflammatory agent." Journal of Ethnopharmacology.
10. Brien S, et al. (2004). "Bromelain as a treatment for osteoarthritis." Evidence-Based Complementary and Alternative Medicine.