Diclofenac (Cataflam, Voltaren, others) - Uses, Side Effects, and More

What are the most common side effects of diclofenac?

The most common side effects of diclofenac are listed below. Side effects may vary based on the specific diclofenac product you are taking. Tell your healthcare provider if you have any of these side effects that bother you.

• Stomach pain or upset stomach
• Constipation or diarrhea
• Nausea or vomiting
• Dizziness
• Drowsiness
• Sweating

There may be other side effects of diclofenac that are not listed here. Contact your healthcare provider if you think you are having a side effect of a medicine. In the U.S., you can report side effects to the FDA at www.fda.gov/medwatch or by calling 800-FDA-1088. In Canada, you can report side effects to Health Canada at www.health.gc.ca/medeffect or by calling 866-234-2345.

What are the serious side effects of diclofenac?

While less common, the most serious side effects of diclofenac are described below, along with what to do if they happen.

Severe Allergic Reactions. Diclofenac can cause allergic reactions, including a specific type of allergic reaction called DRESS. DRESS stands for Drug Reaction with Eosinophilia and Systemic Symptoms. It is also sometimes called multiorgan hypersensitivity. This is a reaction that can affect multiple parts of the body, including your liver, kidneys, and heart. Stop taking the medicine and get help right away if you have any of the following symptoms of a serious allergic reaction.

• Breathing problems or wheezing
• Racing heart
• Fever or general ill feeling
• Swollen lymph nodes
• Swelling of the face, lips, mouth, tongue, or throat
• Trouble swallowing or throat tightness
• Itching, skin rash, or pale red bumps on the skin called hives
• Nausea or vomiting
• Dizziness, feeling lightheaded, or fainting
• Stomach cramps
• Joint pain
• Dark colored urine
• Your skin or the whites of your eyes turning yellowish in color (also called jaundice)

Heart Attack and Stroke. Diclofenac can increase your risk of a heart attack or stroke that can lead to death. This risk is increased in people with existing heart disease and with longer use of diclofenac and higher doses. Do not take diclofenac if you have had a recent heart attack without talking to your healthcare provider. This could increase your risk of having another heart attack. Get emergency help if you have any of the following symptoms of a heart attack or stroke.

• Chest pain or pressure
• Fast or abnormal heartbeat
• Trouble breathing
• Pain in your back, jaw, throat, or arm
• Sweating, upset stomach, vomiting, or dizziness
• Sudden weakness on one side of your body
• Sudden and severe headache
• Slurred speech or trouble understanding speech

Stomach Bleeding. Diclofenac can increase your risk of bleeding, ulcers, and tears (perforation) in your gut. The risk is higher if you have a history of stomach ulcers, bleeding problems, take higher doses of diclofenac or take it for longer than directed, have poor health, are of older age, have liver disease, smoke, drink alcohol, or take certain other medicines. Stop taking diclofenac and get emergency help if you have any of the following symptoms.

• Vomit blood
• Black or tarry poop
• Stomach pain that does not go away
• Upset stomach
• Feel faint

Bleeding. Diclofenac can increase your risk of bleeding, especially if you have a bleeding disorder or take other medicines that increase your risk of bleeding. Tell your healthcare provider right away if you notice signs of bleeding including easy bruising or bleeding.

Anemia. Diclofenac may cause anemia, which is when you have low levels of red blood cells. Tell your healthcare provider if you have any of the following symptoms of anemia.

• Unusual weakness or tiredness
• Cold hands and feet
• Fast or abnormal heartbeat
• Pale or yellowish skin 
• Dizziness, lightheadedness, or feeling like you are about to pass out
• Shortness of breath

Liver Damage. Liver damage, also called hepatotoxicity, can happen when taking diclofenac. Stop taking diclofenac and call your healthcare provider right away if you have any of the following symptoms of liver damage.

• Nausea or vomiting
• Stomach or belly pain
• Fever
• Weakness or unusual tiredness
• Itching
• Loss of appetite
• Light-colored poop
• Dark-colored urine (pee)
• Your skin or the whites of your eyes turning yellowish in color (also called jaundice)

Increased Blood Pressure (Hypertension). Diclofenac may increase your blood pressure or make it worse if you have a history of high blood pressure. Call your healthcare provider if your blood pressure increases while taking this medicine.

If you measure your blood pressure and the top number (systolic) is 180 mm Hg or higher or the bottom number (diastolic) is 120 mm Hg or higher, get medical attention right away. Increases in blood pressure may not be noticeable, but look out for and tell your healthcare provider right away if you have any of the following symptoms of severely high blood pressure.

• Sudden severe headache
• Chest pain
• Dizziness or confusion
• Trouble breathing
• Nausea or vomiting
• Blurry or other changes to vision
• Anxiety
• Buzzing in the ears
• Nosebleed
• Feeling of skipped heartbeats

Fluid Retention (Edema) and Heart Failure. Diclofenac can cause fluid retention, also called edema, which can lead to heart failure. Fluid retention can also cause serious issues in people with heart failure. Stop taking diclofenac and call your healthcare provider right away if you have any of the following symptoms. 

• Shortness of breath
• Stretched or shiny skin
• Swollen body parts, such as the belly or ankles
• Unusually fast weight gain
• Unusual tiredness

Kidney Damage. Kidney damage can happen when taking diclofenac. Call your healthcare provider right away if you have any of the following symptoms of kidney damage.

• Reduced need to pee
• Swelling in your feet, ankles, or legs
• Weakness or unusual tiredness
• Difficulty catching your breath or chest pain/pressure
• Confusion
• Nausea
• Seizures

High Potassium Levels (Hyperkalemia). Diclofenac can cause a high potassium level (hyperkalemia), which can be serious and may lead to death. Your healthcare provider may check your potassium levels, especially if you take certain other medicines. Call your healthcare provider right away if you have any of the following symptoms of a high potassium level. 

• Muscle weakness or unusual tiredness
• Slow heartbeat or feeling of skipped heartbeats 
• Nausea or vomiting
• Trouble breathing
• Abnormal heart rhythm

Severe Skin Reactions. Diclofenac can cause severe skin reactions, called Stevens-Johnson Syndrome (SJS) and Toxic Epidermal Necrolysis (TEN), that can lead to death if not treated. If you develop a rash, stop diclofenac and call your healthcare provider right away. Get emergency help if you have any of the following symptoms of SJS or TEN.

• Painful red or purple skin that looks burned and peels off
• Flat red rash or blisters on your skin, mouth, nose, and genitals
• Red, painful, watery eyes