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Diclofenac is a nonsteroidal anti-inflammatory drug (NSAID) commonly used to reduce inflammation and as an analgesic reducing pain in certain conditions.

Last Modified: 20 May 2024

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What is Diclofenac? 

Diclofenac is a nonsteroidal anti-inflammatory drug (NSAID) commonly used to reduce inflammation and as an analgesic reducing pain in certain conditions. 

Diclofenac is chemically synthesized, with a benzeneacetic acid structure. It functions by inhibiting cyclooxygenase (COX) enzymes, which are involved in the synthesis of prostaglandins, thereby reducing inflammation and pain. 

Global Name

Generic Names: Diclofenac

Global Brand Names:  Voltaren, Cataflam (as the potassium salt), Pennsaid, Flector, Diclofenac Sodium, Zipsor 


What is Diclofenac used for? 

Diclofenac is used to treat a range of conditions including: 

How do you use Diclofenac? 


Diclofenac is available as tablets, capsules, suppositories, creams, gels, and injections. 

Dosage information: 

  • For osteoarthritis: 100-150 mg per day in divided doses 
  • For rheumatoid arthritis: 150-200 mg per day in divided doses 
  • For ankylosing spondylitis: 100-125 mg per day, taken as 25 mg four times a day with an extra 25 mg dose at bedtime if necessary 
  • For menstrual pain: 50 mg three times a day 
  • For acute pain: 50 mg initially, then 50 mg every 8 hours as necessary 


  • Children: Not recommended for children below 6 months of age for most conditions. 
  • Adults: Suitable for adults following the correct dosage for the specific condition. 
  • Elderlies: May require lower dosages due to potential for increased adverse effects. 
  • Allergies: Patients allergic to Diclofenac, aspirin, or other NSAIDs should avoid this medication. 

Is there anyone who can’t take Diclofenac? 

  • Adults: Most adults can take it with caution; however, those with certain medical conditions should avoid it. 
  • Elderlies: Increased risk of side effects; use with caution. 
  • Pregnancy and Lactation: Should be avoided during the third trimester of pregnancy and used with caution during the first and second trimester and while breastfeeding. 
  • Individuals with active gastritis, gastroduodenitis or peptic ulcer disease or active gastrointestinal bleeding 
  • Patients suffering from or at high risk in developing inflammatory bowel disease such as ulcerative colitis and Crohn’s disease. 
  • Patients in severe heart failure 

Any warnings and precautions : 

Diclofenac may increase the risk of serious cardiovascular thrombotic events, myocardial infarction, and stroke. It may also cause serious gastrointestinal adverse events including bleeding, ulceration, and perforation of the stomach or intestines. 

Diclofenac can interact with other medications such as anticoagulants, SSRIs, other NSAIDs, ACE inhibitors, and diuretics.

Side Effects

Common side effects include gastrointestinal discomfort, nausea, diarrhea, dizziness, and headache. Serious side effects may include increased blood pressure, heart problems, liver issues, kidney injury, severe allergic reactions, and gastric or gastroduodenal ulcerations and bleeding. 

Pharmacist Tips

  • Take with food: To reduce stomach upset, take Diclofenac with food or milk, antacids, H2 antagonists/blockers such as ranitidine & famotidine and or proton pump inhibitors (PPI) like omeprazole and pantoprazole. 
  • Hydration: Maintain adequate hydration to prevent kidney problems. 
  • Avoid lying down: After taking the medication, avoid lying down for at least 10 minutes if taking capsules. 
  • Sun sensitivity: Diclofenac may make your skin more sensitive to sunlight. Use sunscreen and wear protective clothing when outdoors. 
  • Topical application: When using gels or creams, apply them to clean, dry skin and do not cover with a bandage unless instructed. 
  • Storage Information: Store at room temperature, away from moisture and heat. 
  • Handling Instructions: Do not crush, chew, or break an extended-release tablet. Swallow it whole. 


Where is Diclofenac available in Hong Kong?

Diclofenac is a nonsteroidal anti-inflammatory drug (NSAID) commonly used for pain relief and inflammation. In Hong Kong, diclofenac is available under different brand names and formulations, prescription and over the counter (OTC) products. You can find diclofenac in various forms, including tablets, capsules, gels, and creams, at pharmacies and drugstores throughout Hong Kong.  


Can I take Diclofenac for a headache?

Diclofenac is used for the treatment of migraines but is not a typical first-line treatment for general headaches. 

Is Diclofenac stronger than ibuprofen?

Diclofenac and ibuprofen are both NSAIDs and have similar pain-relieving effects, but Diclofenac is often used for more severe pain.

Is Diclofenac available for purchase over the counter?

Lower doses of Diclofenac are available over the counter in some countries, but higher doses require a prescription. Always consult with a healthcare provider before using an NSAID. 

How long does Diclofenac stay in your system? 

The half-life of diclofenac, which is the time it takes for half of the drug to be eliminated from the body, is typically around 1.5 to 2 hours. However, it's important to note that the effects of diclofenac can last longer than its elimination half-life. 

This website provides content related to drug use and medicine for informational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Do not use the information on this website to diagnose or treat a health problem or disease without consulting a qualified healthcare provider. The website's owners and contributors are not liable for any repercussions, adverse effects, or consequences resulting from the use of any medication or information provided herein.

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