Medicines & Supplements A to Z > Diclofenac


Last updated on 22/03/2021.

Overview   |   Dosage   |    Side Effects   |   Precautions  |   Tips  |   Where To Buy  

GENERIC NAME: Diclofenac


BRAND NAME(S) IN HONG KONG: Olfen 奧爾芬, Panaflex 必理絡, Voltaren 服他靈

DRUG CLASS: Analgesic, non-opioid; Nonsteroidal Anti-inflammatory Drug (NSAID)

USED FOR: Pain, fever, reducing inflammation, gout

OTHER DRUGS IN THE SAME CLASS: Aspirin, Ibuprofen, Indomethacin, Mefenamic acid, Naproxen

– 1% (gel)
– 25mg, 50mg, 75mg, 100mg (tablets)
– 25mg/ml (injections)

What is Diclofenac for?

Diclofenac belongs to a class of medications called non-steroidal anti-inflammatory drugs (NSAIDs) like Celecoxib. These drugs are used to treat pain, fever, and reduce inflammation.

Diclofenac is available in many formulations: oral tablets/capsules/powder, topical patches, topical gels, rectal suppositories, eye drops, and injections. Topical forms of Diclofenac allow for direct treatment of the painful site and help to minimize side effects associated with taking Diclofenac by mouth.

Some specific uses of each Diclofenac formulation are as follows:

Diclofenac 24-hour patch
– Symptomatic relief of pain, inflammation and swelling in conditions affecting the joints and muscles

Diclofenac emulgel
– Local treatment of pain, inflammation and swelling caused by sports-related injuries or accidents (eg sprains, bruises, strains, back pain) 

Diclofenac tablets/capsules/powder, and injection (Note: for some products SR stands for sustained release)
– Painful syndromes of the vertebral column (tablets / SR tablets / suppositories / injections)
– Inflammatory forms of rheumatism (tablets / SR tablets / suppositories / injections)
– Post-trauma (tablets / SR tablets / suppositories / injections)
– Post-operative pain and inflammation (tablets / SR tablets / suppositories / injections)
– Acute gout (tablets / suppositories / injections)
– Primary dysmenorrhoea or adnexitis (tablets / SR tablets / suppositories)
– Migraine attacks (suppositories / injections)
– Renal and biliary colic (injection) 

Diclofenac eye drops
– Post-operative inflammation
– Eye pain or discomfort (especially after surgery)

How to use it?

When taking Diclofenac by mouth, take with food to avoid stomach irritation. Your doctor may also prescribe a short course of a proton pump inhibitor (e.g., omeprazolepantoprazole), or a stomach acid reducing antihistamine (e.g., famotidine) to prevent this side effect. 

What follows are some dosage guidelines for each specific form of Diclofenac.

For Diclofenac 24 Hr Patch

To the skin
Apply 1 patch / day to the skin in the painful area

For Diclofenac Emulgel
To the skin
Apply 3-4 times daily to the skin in the painful area and rub-in gently 

For Diclofenac  / Diclofenac SR (sustained release)
Orally using tablets / Rectally using suppositories
75-150 mg/day in divided doses (for immediate-release products: 25-50 mg 2-4 times daily; for sustained-release products: once daily) 

For Diclofenac eye drops
To the eye
Usually 1 drop into the affected eye 4 times daily

What are the side effects of Diclofenac?

Like all NSAIDS (non-steroidal anti-inflammatory drugs), the main side effects of Diclofenac are indigestion, nausea, bleeding, gastric ulcer, and allergic reaction. With long-term use Diclofenac can cause kidney injury, bleeding and increase the risk of a cardiovascular event.

Who should not take Diclofenac?

– Discuss with your doctor if you have a history of:
a. Asthma
b. Urticaria
c. Allergic reactions after taking aspirin/NSAIDs
d. Heart failure
e. Chronic kidney disease
– People who is allergic to diclofenac or any components of it

Pharmacist Tips:

For local pain relief, topical NSAIDs can be used without causing any systemic effects. Topical NSAIDs are useful for people who cannot use oral NSAIDs, for example, people who have a history of ulcer or heart failure.

Do not use more than one product containing NSAIDS at the same time.

Common dosing schedule:
You can take oral Diclofenac with food to reduce gastrointestinal distress.

This schedule is for reference only, adjustments may be made according to individual needs.

Some common medications Diclofenac may interact:
Angiotensin converting enzyme inhibitors (e.g. Captopril, Lisinopril)
Angiotensin II receptor antagonists (e.g. Valsartan, Losartan)
Diuretics (e.g. Furosemide, Hydrochlorothiazide)
– Tricyclic antidepressants (e.g. Amitriptyline, Doxepin)

Please notify your doctor or pharmacist if you are taking the above medication, dosage adjustments might be needed.

Where to buy Diclofenac in Hong Kong?

Diclofenac skin patches/gels are pharmacy only medicines and can be purchased without a prescription in a pharmacy by speaking with the pharmacist. They can be obtained from doctors. To find a pharmacy near you, refer to the list of pharmacies (“Authorized Sellers of Poisons”) from the Hong Kong Department of Health.

Diclofenac tablets/suppositories/injections are prescription only medicines and require a prescription from a doctor to be purchased in a pharmacy. They can also be obtained from doctors. 

For more information about drug names and ingredients, you can visit Hong Kong’s Drug Office at

Need more information?

For detailed information about the use of Diclofenac in children, pregnancy and breastfeeding, and for questions about drug interactions, please check with your pharmacist or doctor.

Disclaimer: our goal is to provide you with the most relevant drug information and common dosage for Hong Kong. This information does not constitute medical advice. For specific treatment recommendations and advice, always discuss with your doctor or pharmacist, and follow the instructions included with your specific medicine.