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Boxed warning:

Using diclofenac can increase your risk of serious and potentially fatal cardiovascular thrombotic events, such as heart attack and stroke. Preexisting cardiovascular disease may increase risk.

Diclofenac should not be used in the setting of coronary artery bypass graft (CABG) surgery.

The drug can also increase your risk of serious gastrointestinal adverse events, including bleeding, ulceration, and perforation of the stomach or intestines. These events can occur without warning at any time during treatment with diclofenac. The effects may be fatal.

The risk of these events is higher in older adults, people with a history of gastrointestinal bleeding or ulcers, and people who take diclofenac with certain other medications such as corticosteroids or anticoagulants.¹

You should be closely monitored for any signs of cardiovascular or gastrointestinal adverse effects. To minimize your risk of these events, use the lowest effective dose for the shortest duration possible.²

Avoid diclofenac if you have a history of heart attack or stroke, uncontrolled hypertension, or severe heart failure.

What is diclofenac?

Diclofenac is a non-steroidal anti-inflammatory drug (NSAID).³

The drug is known as a cytochrome c oxidase 1 (COX-1) and cytochrome c oxidase 2 (COX-2) inhibitor. It stops the action of cyclooxygenase, an enzyme that triggers the body’s inflammatory response. Blocking this enzyme shuts down the metabolic pathway and relieves pain and inflammation.

Diclofenac is sold under several brand names, including Cataflam and Zorvolex.

What does oral diclofenac treat?

Diclofenac is approved by the US Food and Drug Administration (FDA) to treat pain and inflammation in adults with the following conditions:⁴

Although diclofenac can relieve the symptoms associated with these conditions, it is not a cure for the underlying disease.

The drug is prescribed off-label for some conditions, meaning it’s not FDA-approved in these cases. Off-label uses include juvenile idiopathic arthritis, postoperative pain in children, pain from gallbladder disease, gout pain, menstrual pain, and muscle pain.

Dosage forms and strengths

Oral diclofenac is available in the form of tablets, capsules, and powders. The following are only available with a prescription and should be taken as directed by your doctor:

  • Delayed-release tablets (generic): 25mg, 50mg, and 75mg⁵

  • Immediate-release tablets (generic): 50mg⁶

  • Extended-release tablets (generic): 100mg⁷

  • Liquid-filled capsules (Zorvolex, Zipsor): 18mg, 25mg, and 35mg⁸ ⁹

  • Powder for solution (generic, Cambia): 50mg¹⁰ ¹¹

Diclofenac is also available for intravenous, intramuscular, rectal, and ophthalmic administration.

Some topical forms, like the gel and patch, are available over the counter (OTC).

How to take oral diclofenac

When taking a diclofenac tablet orally, keep each pill in its original form. Don’t break, crush, or chew the tablets. Some forms of diclofenac are released slowly and must be intact to be effective.

Oral diclofenac is usually prescribed to be taken 2–4 times per day with a full glass of water. If you have an upset stomach when taking diclofenac, contact your doctor. They may suggest taking the medication with food, milk, or a prescribed antacid. Wait 10–15 minutes before lying down after taking your dose.

Powder forms should be totally dissolved in 1–2 ounces of water before drinking. This formulation works best when taken on an empty stomach.¹²

Your doctor may start you at the lowest dosage possible to avoid possible side effects. Do not increase your dosage on your own or take it for a longer period than prescribed.

Seeing results

For most conditions, immediate-release oral diclofenac will start working in around 20–30 minutes. It will reach peak levels within an hour.¹³

Results may vary depending on why you are using the medication. Bear in mind that taking tablets with food slows the drug’s absorption into the bloodstream, delaying its impact.

It might take longer to show signs of improvement if you have particular chronic conditions. This might be because your dosage has been reduced to minimize side effects.

Who should not take diclofenac?

If you take similar NSAIDs for pain, like aspirin, ibuprofen, or naproxen, do not take diclofenac without discussing it with your doctor. These medications can cause an increased risk of adverse effects when combined.

The medication will be unsuitable for you if you have certain other medical conditions. Avoid using the drug if any of the following apply to you:¹⁴

  • Allergy to aspirin or other NSAIDs

  • Aspirin- or NSAID-induced asthma or hives

  • Cardiac bypass surgery (whether you have recently had the surgery or plan to have it)

  • Advanced kidney disease

  • Pregnancy at or beyond 30 weeks of gestation

  • Headache medication overuse

Use caution when taking diclofenac if any of the following apply to you:¹⁵

  • History of/current stomach ulcers or gastrointestinal bleeding

  • History of stroke, pulmonary embolism, or other blood clots

  • Advanced age or debility

  • Recent heart attack

  • Cardiac disease or known risk

  • Congestive heart failure

  • Allergic asthma, rhinitis, or nasal polyps

  • Kidney or liver dysfunction

  • High blood pressure

  • Blood clotting disorder

  • Alcohol use or smoking

  • Phenylketonuria (PKU) — forms that contain phenylalanine

  • Early pregnancy (before 30 weeks) or trying to conceive

Potential side effects of diclofenac

When taking diclofenac, side effects may occur depending on your dosage and the condition being treated.

The more common side effects are typically less severe, but some patients may experience serious side effects and require medical attention.¹⁶ ¹⁷

Common side effects

  • Nausea, vomiting

  • Diarrhea, constipation, gas, bloating

  • Headaches, dizziness

  • Ringing in the ears

  • Stomachache, heartburn

  • Loss of appetite

  • Rash, hives, itchy skin

  • Sleepiness

  • Mild fluid retention, swelling

  • Light sensitivity

Contact your doctor if these side effects persist.

Serious side effects

  • Bloody vomit or stool

  • Severe stomach pain accompanied by vomiting or diarrhea

  • Chest pain

  • Esophagitis

  • Yellowing of the eyes or skin, hepatitis

  • Shortness of breath, wheezing

  • Severe fatigue

  • Leg swelling

  • Unexplained weight gain

  • Severe skin rash with extensive peeling, hives

  • High blood pressure

  • Abnormal blood cell counts

  • Pancreatitis

  • Heart attack

  • Congestive heart failure

  • Prolonged bleeding

  • Stroke or blood clots

  • Liver or kidney injury

  • Life-threatening allergic reactions

Call your doctor immediately if you develop any of the serious side effects listed above.

Call 911 and seek emergency medical help if you develop chest pain, feel lightheaded, have difficulty breathing, become weak on one side of your body, or lose your balance.


Taking more than the recommended dose of diclofenac can lead to diclofenac toxicity.¹⁸

In most cases, the effects are mild and can cause temporary discomfort in the form of nausea, dizziness, and upset stomach. However, with excessive doses, diclofenac toxicity can lead to serious adverse effects. These include gastrointestinal bleeding, seizures, cardiovascular events, kidney failure, high blood pressure, and metabolic abnormalities.¹⁹

Allergy information

Although rare, some people develop a hypersensitivity or severe anaphylactic reaction to diclofenac.

Signs of an anaphylactic reaction include the following:

  • Severe itchy rash, hives, or skin peeling

  • Nausea and vomiting

  • Swelling of the face, tongue, or throat

These may be accompanied by wheezing, difficulty breathing, or even loss of consciousness. Seek immediate medical attention in this case.

Long-term use of diclofenac

Taking oral diclofenac over a long period or in high doses has been known to cause stomach ulcers. Prolonged use, particularly for people with known heart or kidney disease, could cause additional problems such as kidney or liver injury, heart attack, or stroke.²⁰

Diclofenac and pregnancy

Taking diclofenac during pregnancy is not recommended, particularly at 20 weeks of gestation or later. Using NSAIDs, including diclofenac, can cause kidney problems in the fetus. This can result in low levels of amniotic fluid, which may harm the fetus’s growth and development.²¹

Additionally, NSAIDs are known to cause premature closure of the ductus arteriosus in the fetus after 30 weeks of gestation. This is a serious heart condition that negatively impacts circulation in the fetus.²²

If you are pregnant, speak to your doctor about the possible risks of taking diclofenac. Keep in mind that both prescription and OTC medications can contain NSAIDs like diclofenac, so be sure to check with your doctor before taking any drugs.

Diclofenac and breastfeeding

Current research data about diclofenac use in patients who are breastfeeding is limited. However, preliminary studies indicated that low doses (100mg administered orally daily) were undetectable in sampled breast milk.²³

In some cases, diclofenac was detectable in breast milk from patients who received a higher dose. No adverse effects were observed in the nursing infants.

Missed doses

If you miss your scheduled dose, take it as soon as you can. If it’s nearly time for your next dose, skip the missed dose and continue taking your medication as scheduled.

Drug interactions

Combining diclofenac with certain medications can be dangerous and cause serious side effects.

Diclofenac can interact with the following drugs:²⁴

  • Other NSAIDs, such as ibuprofen (Motrin, Advil), aspirin, celecoxib (Celebrex), meloxicam (Mobic), and naproxen (Naprosyn) — taking these drugs with diclofenac can increase your risk of developing adverse effects (such as ulcers, gastrointestinal bleeding, kidney failure, and cardiovascular events) or worsen them.

  • Blood thinners, such as enoxaparin (Lovenox), apixaban (Eliquis), and amlodipine (Norvasc) — these medications can increase the risk of serious bleeding and other cardiac-related complications when taken with diclofenac

  • Blood pressure medications, such as angiotensin-converting enzyme (ACE) inhibitors like lisinopril (Zestril) and beta-blockers like atenolol (Tenormin)

  • Steroid medicines, such as betamethasone (Beta-Val, Dermabet), prednisone (Rayos, Prednisone Intensol), hydrocortisone, and dexamethasone (Decadron, Dexamethasone Intensol, Dexpak Taperpak)

  • Ergot alkaloid migraine medications like ergotamine (Ergomar)

  • Antibiotics like penicillin, piperacillin, rifampin, gentamicin, and tobramycin (Tobrex)

  • Antiviral medicines, such as acyclovir (Zovirax)

  • Decongestants, such as phenylephrine (NeoSynephrine, Sudafed)

  • Chemotherapy drugs, such as capecitabine (Xeloda) and carboplatin (Paraplatin)

  • Disulfiram (Antabuse)

  • Acetaminophen (Tylenol)

  • Lithium (Lithobid)

  • Digoxin (Lanoxin)

  • Cannabidiol (Epidiolex), dronabinol (Marinol)

  • Sodium phosphate bowel prep (Osmoprep)

  • Alcohol

  • Recreational drugs such as cocaine, methamphetamine, and marijuana

  • Other: evening primrose oil, fenugreek, ginkgo, krill oil, licorice, milk thistle, saw palmetto, and caffeine

This is not an exhaustive list. You should tell your doctor about all prescription and OTC medicines and supplements you take either regularly or occasionally.

Can I drink alcohol while taking diclofenac?

Caution is recommended if drinking alcohol while taking diclofenac. It may increase your risk of gastric ulcers and life-threatening GI bleeding or perforation.²⁵

The best thing you can do is speak to your doctor and ask how to consume alcohol safely while taking this medication.

What to discuss with your doctor before starting diclofenac

Before you start taking diclofenac, discuss the following things with your doctor:²⁶

  • Any medical conditions you have, particularly liver or kidney disease, asthma, porphyria, heart disease or heart failure, PKU, high blood pressure, or gastric ulcer

  • History of gastrointestinal bleeding or recent heart attack or stroke

  • Any and all medications, herbal medicines, supplements, and vitamins you take, either by prescription or OTC

  • Past history of allergies or reactions to medications, especially to NSAIDs

  • Pregnancy, breastfeeding, or plans to conceive

  • Planned surgeries (especially cardiac surgery) or dental procedures

Stopping diclofenac

Stopping diclofenac does not cause any serious side effects. However, the condition you are taking it for might worsen. Talk to your doctor to make a plan for safely discontinuing diclofenac.

Drug approval history

Diclofenac was first approved by the FDA in 1988 in the form of enteric-coated tablets. Since then, various forms have been approved, including immediate-release tablets and oral solutions.²⁷

Tips for taking diclofenac

  • Always take diclofenac with a full glass of water when taking it in tablet or capsule form.

  • Tell your doctor if you have any heart or kidney disease before taking diclofenac.

  • Watch closely for signs of gastrointestinal side effects, such as indigestion, abdominal pain, and bloody vomit or stools.

  • Pregnant women should avoid taking diclofenac, especially after 20 weeks of pregnancy. 

  • Check with your doctor before taking any OTC medicines alongside diclofenac to avoid adverse drug interactions.

  • Store your medicine in a dry place at room temperature. Keep it out of the reach of children. 

Frequently asked questions

What should I avoid when taking diclofenac?

Do not take other NSAIDs or steroids when taking diclofenac as this could worsen their adverse effects on the stomach, heart, and kidneys.

Consume alcohol and caffeinated drinks with caution.

Should diclofenac be taken every day or just as needed?

Always take diclofenac as prescribed by your doctor, with the correct dosages and intervals.

Can you drink coffee when taking diclofenac?

Diclofenac can cause stomach irritation. For that reason, it’s best to avoid drinking caffeinated beverages and alcohol.

  1. Diclofenac l MedlinePlus

  2. Diclofenac (2023) l NIH: StatPearls

  3. (As above)

  4. Voltaren XR, Cataflam (diclofenac) dosing, indications, interactions, adverse effects, and more l Reference Medscape

  5. LABEL: DICLOFENAC SODIUM tablet, delayed release (2021) l NIH: DailyMed

  6. LABEL: DICLOFENAC POTASSIUM- diclofenac potassium, film coated tablet (2023) l NIH: DailyMed

  7. LABEL: DICLOFENAC SODIUM tablet, extended release (2023) l NIH: DailyMed

  8. LABEL: ZORVOLEX- diclofenac capsule (2021) l NIH: DailyMed

  9. LABEL: ZIPSOR- diclofenac potassium capsule, liquid filled (2021) l NIH: DailyMed

  10. Label: DICLOFENAC POTASSIUM powder, for solution (2022) l NIH: DailyMed

  11. LABEL: CAMBIA- diclofenac potassium powder, for solution (2021) l NIH: DailyMed

  12. Label: DICLOFENAC POTASSIUM powder, for solution (2022) l NIH: DailyMed

  13. Voltaren XR, Cataflam (diclofenac) dosing, indications, interactions, adverse effects, and more l Reference Medscape

  14. Diclofenac l MedlinePlus

  15. diclofenac sodium: Dosing, contraindications, side effects, and pill pictures l epocrates online

  16. Voltaren XR, Cataflam (diclofenac) dosing, indications, interactions, adverse effects, and more l Reference Medscape

  17. Diclofenac l MedlinePlus

  18. Diclofenac (2023) l NIH: StatPearls

  19. LABEL: DICLOFENAC POTASSIUM- diclofenac potassium, film coated tablet (2023) l NIH: DailyMed

  20. Diclofenac (2023) l NIH: StatPearls

  21. FDA recommends avoiding use of NSAIDs in pregnancy at 20 weeks or later because they can result in low amniotic fluid (2023)

  22. (As above)

  23. Diclofenac (2023) l NIH: Drugs and Lactation Database

  24. Diclofenac l MedlinePlus

  25. diclofenac sodium: Dosing, contraindications, side effects, and pill pictures l epocrates online

  26. Diclofenac l MedlinePlus

  27. Advances in NSAID Development: Evolution of Diclofenac Products Using Pharmaceutical Technology (2015)

Curious about clinical trials?

Access the latest treatments and medications. unavailable elsewhere - entirely free of charge. We make it easy to take part.


Here at HealthMatch, we’ve done our best to ensure that the information provided in this article is helpful, up to date, and, most importantly, accurate.

However, we can’t replace the one-to-one advice of a qualified medical practitioner or outline all of the possible risks associated with this particular drug and your circumstances.

It is therefore important for you to note that the information contained in this article does not constitute professional medical or healthcare advice, diagnosis or recommendation of treatment and is not intended to, nor should be used to, replace professional medical advice. This article may not always be up to date and is not exhaustive of all of the risks and considerations relevant to this particular drug. In no circumstances should this article be relied upon without independent consideration and confirmation by a qualified medical practitioner.

Your doctor will be able to explain all possible uses, dosages, precautions, interactions with other drugs, and other potential adverse effects, and you should always talk to them about any kind of medication you are taking, thinking about taking or wanting to stop taking.

Curious about clinical trials?

Access the latest treatments and medications. unavailable elsewhere - entirely free of charge. We make it easy to take part.