Diclofenac: Uses, Side Effects, Risks and Safety Tips

6 min read · Medicines · By the Asthra Health Care team

What diclofenac is used for

Diclofenac is a non-steroidal anti-inflammatory drug, or NSAID. Doctors use it to relieve pain and swelling in conditions such as osteoarthritis, rheumatoid arthritis, back pain, sprains, gout attacks, dental pain and pain after minor surgery. It is also available as a gel applied to the skin for sore muscles and joints.

Diclofenac is one of the most widely used painkillers in India, and it is often found in combination tablets and injections given at clinics. Because it is so common, many people use it more often than is safe. It relieves symptoms but does not repair worn joints or treat the cause of pain.

• Knee and joint pain from arthritis
• Back pain, neck pain and muscle sprains
• Acute gout attacks and dental pain
• Pain after minor operations or injuries

How diclofenac works

Diclofenac blocks the enzymes that produce prostaglandins, chemicals that cause pain, swelling and fever at the site of injury. With fewer prostaglandins, the joint or muscle becomes less painful, less swollen and easier to move. This makes diclofenac useful in flare-ups of arthritis or after injuries, where swelling is a large part of the pain.

Prostaglandins also protect the stomach lining, keep blood flowing to the kidneys and help regulate blood pressure. Blocking them strongly, as diclofenac does, explains its main risks: acidity and ulcers, kidney strain and effects on the heart and blood vessels.

Diclofenac side effects: common and serious

Common side effects include acidity, heartburn, nausea, stomach pain, loose stools, headache and dizziness. The gel form can cause redness or itching where it is applied, but it has fewer whole-body effects because less of the medicine reaches the blood.

Serious effects include stomach ulcers and bleeding, kidney damage, raised blood pressure, fluid retention and liver irritation. Among NSAIDs, diclofenac is known to carry a higher risk of heart attack and stroke, particularly with regular use or in people who already have heart disease. Rarely, it can cause serious allergic reactions or severe skin rashes.

Who should avoid diclofenac or take extra care

People with heart disease, a past heart attack or stroke, heart failure, poorly controlled blood pressure, kidney disease, liver disease or a history of stomach ulcers should generally avoid diclofenac unless a doctor specifically advises it. It should also be avoided when dengue is suspected, because it increases bleeding risk.

Diclofenac is usually avoided in pregnancy, especially in the last three months, because it can harm the baby's heart and kidneys. Ask your doctor before using it while breastfeeding. Elderly people, people with asthma triggered by painkillers and those who are dehydrated need extra caution. It is not usually a first choice for children.

Diclofenac interactions to know

Never take diclofenac along with another NSAID such as ibuprofen, aceclofenac, naproxen or aspirin for pain. Combining them raises the risk of stomach bleeding and kidney damage. With blood thinners, steroid tablets or some antidepressants, the chance of bleeding also goes up.

Diclofenac can reduce the effect of blood pressure medicines and, together with ARBs, ACE inhibitors or water tablets, can seriously harm the kidneys, especially during vomiting, diarrhoea or hot weather. It can also raise the levels of lithium, methotrexate and some diabetes medicines. Share your full medicine list with your doctor or chemist.

Practical tips for safe use

Diclofenac tablets and injections should only be used as a doctor or pharmacist advises, for the shortest time possible. Take tablets after food with water. Do not accept repeated painkiller injections for back or knee pain without understanding what is being given and why.

For long-lasting joint pain, a diclofenac gel on the skin is often a safer choice than tablets. Weight control, regular gentle exercise, physiotherapy and hot or cold packs can reduce the need for painkillers. Keep drinking enough water, particularly in summer.

When to talk to your doctor about diclofenac

If you need diclofenac for more than a few days, or keep going back to it every week, see a doctor to find the cause of the pain and discuss safer long-term treatment. Get urgent help for chest pain, breathlessness, black stools or reduced urine. Speak to your doctor or pharmacist before starting it if you have any heart, kidney or stomach problem.

This article is general health information, not medical advice. Do not start, stop or combine medicines on your own — always follow your doctor's prescription and ask your pharmacist if unsure.