Diclofenac (Voltaren)

Diclofenac (Voltaren) is a nonsteroidal anti-inflammatory drug (NSAID) used to relieve pain, swelling, and stiffness from conditions such as osteoarthritis, rheumatoid arthritis, and other musculoskeletal pain. Diclofenac (Voltaren) is used for Osteoarthritis and rheumatoid arthritis and Localised muscle or joint pain (topical gel/solution).

Also called: Xiclo (United States) · Arthrotec (United Kingdom) · Pennsaid (Canada) · Fenac (Australia) · Difenax (Philippines)

Pronunciation: dye-KLOE-fen-ak.

Generic name
diclofenac
Brand names
Voltaren, Voltarol
Drug class
Nonsteroidal anti-inflammatory drug (NSAID)
Form
Tablets (immediate or delayed/extended release), injection, suppositories, topical gel, or topical solution
Route
Oral, injection (intramuscular), suppository (rectal), or topical (skin)
Legal status
Prescription-only for oral tablets, injection, and suppositories in most markets; some low-strength topical gel products are available over the counter (e.g. Voltaren Gel in the US, Voltarol Emulgel/Pain Relief Gel in the UK/Australia).

Availability and supply rules vary by country

Trade names by country: United States · United Kingdom · Canada · Australia · India · Nepal · New Zealand

Australia: Voltaren, Fenac EC, DICLOFENAC-WGR, Diclofenac Sandoz, Clonac, Dofidaz, Solaraze · Full directory

What diclofenac is and how it works

Diclofenac (Voltaren) is a nonsteroidal anti-inflammatory drug (NSAID) used to relieve pain, swelling, and stiffness from conditions such as osteoarthritis, rheumatoid arthritis, and other musculoskeletal pain. It comes as oral tablets, an injection, suppositories, and a topical gel or solution applied to the skin. (1) (3) (2)

All NSAIDs, including diclofenac, carry a real risk of serious heart and stomach/intestinal problems -- this is why diclofenac (in oral, injectable, and suppository forms) carries an official boxed warning in the US, and why UK/EU regulators specifically restrict its use in people with cardiovascular risk factors. Topical (skin) diclofenac has much lower whole-body exposure and is generally considered lower risk, but is not risk-free and still carries the same boxed warning on its approved US label. Take the lowest effective dose for the shortest time your prescriber recommends, and always confirm which exact formulation and strength you have.

Mechanism of action: how diclofenac works

Diclofenac is a nonsteroidal anti-inflammatory drug that inhibits cyclo-oxygenase (COX-1 and COX-2), reducing prostaglandin synthesis and thereby reducing pain, inflammation, and fever. Its cardiovascular thrombotic risk profile at systemic doses has been found comparable to selective COX-2 inhibitors by EU regulators. (1) (3)

What is Diclofenac used for?

Osteoarthritis and rheumatoid arthritis

Used to relieve the signs and symptoms (pain, swelling, and stiffness) of osteoarthritis and rheumatoid arthritis. (1)

Ankylosing spondylitis, acute musculoskeletal pain, migraine, and gout

Used for ankylosing spondylitis, acute musculoskeletal disorders, low back pain, acute gout, migraine attacks, and perioperative pain, depending on the country and formulation. (1) (3)

Localised muscle or joint pain (topical gel/solution)

Topical diclofenac gel or solution is used for localised pain from conditions like osteoarthritis of joints close to the skin surface (such as the hands or knees), with much lower whole-body exposure than oral use. (2)

Before taking diclofenac

Do not take / not appropriate for

  • Do not take oral, injectable, or suppository diclofenac if you have had a heart bypass (CABG) operation, or in the period around planned CABG surgery. (all countries) (1)
  • Do not take diclofenac if you have an active stomach or intestinal ulcer, bleeding, or perforation, or a history of GI bleeding/perforation linked to NSAID use. (all countries) (3) (7)
  • Do not take diclofenac during the third trimester of pregnancy (the last three months). (all countries) (3) (7) (6)
  • Do not take diclofenac if you have had asthma, hives, or an allergic reaction triggered by aspirin or another NSAID. (all countries) (1) (3)
  • Do not take oral or injectable diclofenac if you have established heart failure, ischaemic heart disease, peripheral arterial disease, cerebrovascular disease, or severe liver or kidney failure. (United Kingdom / European Union) (3)

Tell your clinician about

  • Any history of heart disease, high blood pressure, stroke, or risk factors such as smoking, diabetes, or high cholesterol.
  • Any history of stomach ulcers, GI bleeding, or liver or kidney problems.
  • Whether you are pregnant, trying to become pregnant, or breastfeeding.
  • All other medicines you take, especially other NSAIDs, aspirin, blood thinners, lithium, methotrexate, ACE inhibitors or ARBs, diuretics, or corticosteroids.
  • Which exact diclofenac product and strength you have been prescribed or are considering, since oral, injectable, suppository, and topical forms carry different levels of whole-body exposure.
(1) (3)

Diclofenac dosage and how to take it

  • Take diclofenac exactly as your prescriber or the product label directs, using the lowest effective dose for the shortest time needed.
  • Take oral tablets with food or milk if stomach upset occurs, and swallow delayed/extended-release tablets whole without crushing or chewing.
  • For topical gel or solution, apply only to intact (unbroken) skin over the affected area, wash your hands after use (unless treating the hands), and avoid covering the area with an airtight dressing unless directed.
  • Do not combine diclofenac with another oral NSAID, including OTC ibuprofen or naproxen, unless your prescriber has specifically told you to.
(1) (3)

Procedures and treatment changes

Tell the treating team before surgery, procedures, or any medicine change. Do not alter treatment without the responsible clinician. (1) (2) (3) (4) (5) (6) (7)

Missed dose

If you take diclofenac on a regular schedule and miss a dose, take it as soon as you remember unless it is almost time for your next dose, in which case skip the missed dose and continue your normal schedule -- do not take a double dose to make up for a missed one. Contact your pharmacist or prescriber if you are unsure.

Overdose

Seek emergency medical help or contact a poison-control service immediately if an overdose is suspected. Symptoms can include severe stomach pain, nausea, vomiting, drowsiness, dizziness, and, in serious cases, gastrointestinal bleeding, seizures, or kidney problems. (1)

Diclofenac side effects

Side effects and their urgency vary; report severe, persistent, or concerning symptoms.

Headache, dizziness.

What to notice: Headache, dizziness.

What to do: Discuss persistent or troublesome symptoms with the treating clinician or pharmacist. (3)

Nausea, vomiting, diarrhoea, indigestion (dyspepsia), and abdominal pain.

What to notice: Nausea, vomiting, diarrhoea, indigestion (dyspepsia), and abdominal pain.

What to do: Discuss persistent or troublesome symptoms with the treating clinician or pharmacist. (3)

Skin rash.

What to notice: Skin rash.

What to do: Discuss persistent or troublesome symptoms with the treating clinician or pharmacist. (3)

With topical gel: application-site irritation, dryness, or redness.

What to notice: With topical gel: application-site irritation, dryness, or redness.

What to do: Discuss persistent or troublesome symptoms with the treating clinician or pharmacist. (2)

Serious warnings

Signs of a heart attack or stroke — boxed_warning

Symptoms: Chest pain or pressure that may spread to the neck, jaw, or shoulders; shortness of breath; sudden weakness or numbness on one side of the body; slurred speech.

Action: Seek emergency medical help immediately. This is the real, FDA-mandated boxed-warning risk shared by all NSAIDs, including diclofenac, and can occur even without prior heart symptoms. (1) (5)

Signs of serious gastrointestinal bleeding, ulceration, or perforation — boxed_warning

Symptoms: Black or tarry stools, vomiting blood or material that looks like coffee grounds, or severe stomach pain.

Action: Seek emergency medical help immediately. This is the real, FDA-mandated boxed-warning GI risk, which can occur at any time during treatment, with or without earlier warning symptoms. (1) (5)

Signs of a serious allergic (anaphylactic) reaction — emergency

Symptoms: Swelling of the face, lips, tongue, or throat; difficulty breathing; widespread hives or rash.

Action: Seek emergency medical help immediately, especially if you have previously had asthma or an allergic reaction to aspirin or another NSAID. (1) (3)

Signs of a serious skin reaction — emergency

Symptoms: Widespread rash, blistering or peeling skin, or sores in the mouth.

Action: Seek emergency or urgent medical help immediately; a clinician will assess whether diclofenac needs to be stopped. These reactions (including Stevens-Johnson syndrome and toxic epidermal necrolysis) are rare but can be serious, and risk is highest early in treatment. (3)

Signs of a possible liver problem — high caution

Symptoms: Unusual tiredness, loss of appetite, yellowing of the skin or eyes, dark urine, or upper right abdominal pain.

Action: Contact your prescriber promptly for liver-function testing; a clinician will decide on next steps, which may include stopping diclofenac. (1) (3)

Signs of fluid retention or worsening heart failure — high caution

Symptoms: Swelling in the legs or ankles, sudden weight gain, or shortness of breath.

Action: Contact your prescriber promptly; NSAIDs including diclofenac can cause fluid retention and have been linked to a higher risk of heart-failure hospitalisation. (1)

Interactions

  • Aspirin: combining with diclofenac is not generally recommended, as it can reduce diclofenac's protein binding without improving overall benefit. (1)
  • Other NSAIDs (including OTC ibuprofen/naproxen) or corticosteroids: increase the risk of GI bleeding and ulceration when combined with diclofenac. (3)
  • Blood thinners (anticoagulants) such as warfarin: increased bleeding risk. (1) (3)
  • Methotrexate: diclofenac can increase methotrexate levels and toxicity; avoid taking within 24 hours of a methotrexate dose. (3)
  • Lithium and digoxin: diclofenac can raise blood levels of these medicines; monitoring may be needed. (3)
  • ACE inhibitors, ARBs, and diuretics ('water tablets'): diclofenac can reduce their blood-pressure-lowering effect and increase the risk of kidney problems when combined. (1)
  • Ciclosporin or tacrolimus: increased risk of kidney toxicity when combined with diclofenac. (3)

Pregnancy, breastfeeding, kidney/liver function, age

Pregnancy

Avoid diclofenac in the first and second trimesters of pregnancy unless your prescriber decides it is clearly needed, using the lowest dose for the shortest time. Diclofenac is contraindicated in the third trimester of pregnancy because it can affect the baby's circulation (constriction of the ductus arteriosus) and kidney function, and increase the risk of bleeding. (3) (1) (6)

Breastfeeding

Oral and injectable diclofenac should generally not be used while breastfeeding, to avoid exposing the infant to the medicine; discuss any need for pain relief while breastfeeding with your prescriber. (3) (1) (6)

Children

Safety and effectiveness of oral diclofenac have not been established in children in the US label reviewed; some other countries permit use from a specified age for specific conditions -- follow your local product information and prescriber's guidance. Not for use in children under 12 months for suppositories, per the Australian CMI reviewed. (3) (1) (6)

Elderly

Older adults are at higher risk of serious GI, cardiovascular, and kidney complications from NSAIDs; use the lowest effective dose for the shortest time, with extra caution. (3) (1) (6)

Hepatic Impairment

Close medical monitoring is required, including regular liver-function tests during prolonged use; diclofenac is contraindicated in hepatic failure. (3) (1) (6)

Renal Impairment

Use with caution and close monitoring in mild-to-moderate kidney impairment; contraindicated in renal failure and advanced kidney disease; maintain adequate hydration. (3) (1) (6)

Monitoring

Before starting

  • Assessment of cardiovascular risk factors (blood pressure, heart disease, stroke history)
  • Assessment of GI bleeding/ulcer history
  • Baseline liver and kidney function where prolonged use is planned

During treatment

  • Blood pressure checks, since NSAIDs can raise blood pressure.
  • Liver-function tests, typically within the first 4-8 weeks and periodically thereafter during prolonged use.
  • Kidney function tests, especially in those with existing kidney disease, heart failure, or on interacting medicines.
  • Watching for signs of GI bleeding, allergic reaction, or skin reaction throughout treatment.
(1) (3)

Storage

Store tablets at room temperature, away from moisture and heat. Store topical gel/solution as directed on the label, tightly closed. Keep all forms out of reach of children.

Professional information

Clinician-facing context only, sourced from the current US FDA prescribing information and UK/EU/Canada/Australia/New Zealand regulator sources; verify against the current full label before prescribing, and confirm the exact formulation (oral, injectable, suppository, or topical) in use.

United States

Indication: Osteoarthritis, rheumatoid arthritis, ankylosing spondylitis (oral delayed-release tablets)

Dose summary: Osteoarthritis 100-150 mg/day divided; rheumatoid arthritis 150-200 mg/day divided; ankylosing spondylitis 100-125 mg/day divided. Use lowest effective dose, shortest duration. Contraindicated in the CABG perioperative setting.

Renal context: Avoid in advanced renal disease; use caution and monitor in dehydration or pre-existing renal impairment. (1)

United Kingdom

Indication: Rheumatoid arthritis, osteoarthrosis, ankylosing spondylitis, acute musculoskeletal disorders, migraine, acute gout, perioperative pain

Dose summary: Typically 75-150 mg/day in divided doses depending on indication; migraine-specific regimen (50 mg at onset, additional 50 mg every 4-6 hours, max 200 mg/day). Contraindicated in NYHA II-IV heart failure, ischaemic heart disease, peripheral arterial disease, cerebrovascular disease, and third-trimester pregnancy.

Renal context: Caution in mild-to-moderate renal impairment with monitoring; contraindicated in renal failure. (3)

Mechanism of action

Hepatic guidance

A clinician will decide whether treatment needs to be discontinued if signs of liver dysfunction develop or persist, or if liver-function tests remain abnormal or worsen; obtain baseline and periodic liver-function tests during prolonged use.

Overdose note

Overdose can cause GI symptoms (pain, nausea, vomiting), CNS effects (drowsiness, dizziness, seizures in severe cases), and renal impairment; manage supportively per local poison-control/toxicology guidance; no specific antidote. (1) (3)

Frequently asked questions

Why does diclofenac have a boxed warning?

Diclofenac, like all NSAIDs, carries an FDA boxed warning because it increases the risk of serious heart attack, stroke, and gastrointestinal bleeding, ulceration, or perforation, which can be fatal. This risk exists with oral, injectable, and suppository use, and to a much lesser but non-zero extent with topical use. It is contraindicated around coronary artery bypass graft (CABG) surgery. (1)

Is diclofenac gel as risky as diclofenac tablets?

No -- topical diclofenac gel has substantially lower whole-body (systemic) exposure than oral tablets, roughly 6% of the oral systemic exposure at labeled use. However, some absorption still occurs, and the FDA-approved topical gel label still carries the same class boxed warning as oral diclofenac, so it is not risk-free. (2)

Can I take diclofenac while pregnant?

Diclofenac should be avoided in the first two trimesters unless your prescriber decides it is clearly necessary, and it is contraindicated in the third trimester of pregnancy because of effects on the baby's circulation and kidneys, and increased bleeding risk. (3) (7)

Is diclofenac available in the US, UK, Europe, Canada, Australia, and New Zealand?

Yes, diclofenac in one or more formulations (oral, injectable, suppository, or topical) is approved and available in all of these regions. (1) (4) (3) (5) (6) (7)

What is the mechanism of action of diclofenac?

Diclofenac is a nonsteroidal anti-inflammatory drug that inhibits cyclo-oxygenase (COX-1 and COX-2), reducing prostaglandin synthesis and thereby reducing pain, inflammation, and fever. Its cardiovascular thrombotic risk profile at systemic doses has been found comparable to selective COX-2 inhibitors by EU regulators. (1) (3)

What is the generic name of Diclofenac (Voltaren)?

The generic name is diclofenac. It is sold under brand names including Voltaren, Voltarol. (1) (2)

What class of drug is diclofenac?

Diclofenac (Voltaren) is classed as: Nonsteroidal anti-inflammatory drug (NSAID). (1) (2)

References

  1. VOLTAREN (diclofenac sodium delayed-release tablets) -- full prescribing informationU.S. Food and Drug Administration / DailyMed, full prescribing information for VOLTAREN (diclofenac sodium delayed-release tablets) · United States · dated 2026-01-01 · accessed 2026-07-29 · source 1
  2. VOLTAREN GEL (diclofenac sodium topical gel), 1% -- prescribing informationU.S. Food and Drug Administration, approved labeling for VOLTAREN GEL (diclofenac sodium topical gel, 1%) · United States · dated 2018-01-01 · accessed 2026-07-29 · source 2
  3. Voltarol Rapid 50 mg Tablets -- Summary of Product Characteristicselectronic medicines compendium (emc), United Kingdom -- Summary of Product Characteristics for Voltarol Rapid 50 mg Tablets (diclofenac potassium), Novartis Pharmaceuticals UK Ltd · United Kingdom · dated 2026-01-01 · accessed 2026-07-29 · source 3
  4. New safety advice for diclofenac -- Article 31 referral, PRAC recommendation endorsed by CMDhEuropean Medicines Agency (EMA), Pharmacovigilance Risk Assessment Committee (PRAC) Article 31 referral outcome on diclofenac · European Union · dated 2013-06-01 · accessed 2026-07-29 · source 4
  5. VOLTAREN and VOLTAREN SR (diclofenac sodium) -- Product MonographHealth Canada, product monograph for VOLTAREN / VOLTAREN SR (diclofenac sodium) · Canada · dated 2026-01-01 · accessed 2026-07-29 · source 5
  6. VOLTAREN diclofenac sodium tablets/suppositories -- ARTG entries and Consumer Medicine InformationTherapeutic Goods Administration (TGA), Australia -- ARTG registrations and Consumer Medicine Information for Voltaren (diclofenac sodium) · Australia · dated 2026-01-01 · accessed 2026-07-29 · source 6
  7. Voltaren (diclofenac sodium) -- New Zealand Data SheetMedsafe (New Zealand regulator), New Zealand Data Sheet for Voltaren (diclofenac sodium) · New Zealand · dated 2026-01-01 · accessed 2026-07-29 · source 7

Brand names by country

Single-ingredient diclofenac names are shown separately by country. Product availability, strengths, and supply rules can change; combination products are not included here.

Priority countries

United States

India

Source-listed products; local stock and regulatory approval have not been confirmed. Check the exact ingredient, strength, and formulation with a pharmacist.

  • Reactin 100 SR TabletTablet PR · 100mg · Cipla Ltdpharmacy source · checked 2026-09-24
  • Zeldinac 100 Tablet SRTablet SR · 100mg · Leeford Healthcare Ltdpharmacy source · checked 2026-09-24
  • Zeldinac Transdermal PatchTransdermal Patch · 200mg · Leeford Healthcare Ltdpharmacy source · checked 2026-09-24
  • Dikloflame InjectionInjection · 25mg · Intas Pharmaceuticals Ltdpharmacy source · checked 2026-09-24
  • Diklotas 25mg InjectionInjection · 25mg · Intas Pharmaceuticals Ltdpharmacy source · checked 2026-09-24
  • Aldigesic InjectionInjection · 75mg · Alkem Laboratories Ltdpharmacy source · checked 2026-09-24
  • Vovedic InjectionInjection · 75mg · Leeford Healthcare Ltdpharmacy source · checked 2026-09-24
  • Powerflam InjectionInjection · NA · Alkem Laboratories Ltdpharmacy source · checked 2026-09-24

Nepal

Source-listed products; local stock and regulatory approval have not been confirmed. Check the exact ingredient, strength, and formulation with a pharmacist.

  • A FenacInjection · 75mg · Acme Laboratories Ltdreference source · checked 2026-09-24
  • Atune DTTablet · 50mg · Panas Pharmaceutical Pvt. Ltd.reference source · checked 2026-09-24
  • C NacTablet · 50mg · Chemi Drug Industries Pvt. Ltd.reference source · checked 2026-09-24
  • CerinCapsule · 50mg · Maruti Pharma Pvt. Ltd.reference source · checked 2026-09-24
  • ClofenacTablet · 50mg · Square Pharmaceuticals Ltd.reference source · checked 2026-09-24
  • ClonacGel · 1% · Curex Pharmaceuticals Pvt. Ltd.reference source · checked 2026-09-24
  • DackTablet · 50mg · Magnus Pharma Pvt. Ltd.reference source · checked 2026-09-24
  • DiacerTablet · 50mg · Apex Pharmaceuticals Pvt. Ltd.reference source · checked 2026-09-24
View brands in additional countries.

Philippines

Voltaren, Difenax, Neo Pyrazon

European Union

Diclofenac-containing medicines (nationally authorised across member states; EU-wide cardiovascular safety review conducted centrally by EMA/PRAC) (4)

This page provides general reference information about diclofenac (Voltaren) and is not a substitute for advice from the prescriber or pharmacist managing your treatment. All dosing and treatment decisions, including which formulation is right for you, should be made with your prescriber.

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