Diclofenac: Uses, Side Effects & Safety

What it is and what it's used for

Diclofenac belongs to a group of medicines called NSAIDs — non-steroidal anti-inflammatory drugs. It reduces pain, swelling and stiffness, which is why it is commonly used for joint pain and arthritis, backache, muscle sprains, dental pain and period cramps. It also helps reduce fever, though it is less often used for that purpose.

In India, oral diclofenac tablets are a Schedule H medicine, meaning they should be taken on a doctor's prescription. The topical gel form, on the other hand, is widely sold over the counter and is commonly used for localised muscle or joint pain.

How it works (simple language)

Pain and inflammation in the body are partly caused by natural chemicals called prostaglandins. Diclofenac is thought to work by blocking the enzymes (called COX-1 and COX-2) that make these chemicals. With fewer prostaglandins produced, swelling goes down and pain eases. The gel works in the same way, but mainly where it is applied, so less medicine reaches the rest of the body.

Dosage forms available in India (general info only)

Diclofenac is available in India as 50 mg tablets, 100 mg sustained-release tablets and capsules, a 1% gel for applying on the skin (the widely known brand Volini is one example), eye drops for certain eye conditions, and an injectable form used in hospitals. The popular oral brand Voveran is one well-known example; many other brands exist.

Never decide the dose yourself from this article. Always follow your doctor's prescription or the directions on the pack, and check with your pharmacist if you are unsure — especially for children, where the dose depends on the child's weight and age.

Side effects

Common: Stomach pain, nausea, indigestion, heartburn, gas and diarrhoea. These are the most frequently reported side effects, especially when the tablet is taken on an empty stomach. The gel may cause mild redness, itching or irritation where it is applied.

Serious — seek medical care: Black or tarry stools, vomiting that looks like coffee grounds, or vomiting blood can signal stomach bleeding. Chest pain, sudden breathlessness, or weakness on one side of the body may indicate heart or stroke problems, which long-term or high-dose use can raise the risk of. Also seek care for swelling of the face, lips or tongue, difficulty breathing or wheezing (signs of allergy — people allergic to aspirin can react badly to diclofenac), very little or no urine, yellowing of the skin or eyes, or a severe skin rash with blisters.

Precautions and warnings

• Take with food or milk. Diclofenac can irritate the stomach lining; taking it with food or milk lowers the chance of pain, heartburn and ulcers.
• Do not combine with other NSAIDs. Using it together with other painkillers of the same type (like ibuprofen or naproxen) increases side effects without extra benefit.
• Caution with heart, blood pressure and kidney problems. Long-term or high-dose use can raise the risk of heart attack and stroke, worsen blood pressure, and strain the kidneys — your doctor should know about these conditions.
• Avoid alcohol. Alcohol together with diclofenac increases the risk of stomach bleeding.
• Allergy alert. If aspirin or other painkillers have ever caused wheezing, a runny nose, rashes or swelling in you, tell your doctor before using diclofenac — a similar reaction is possible.
• Elderly people need extra care. Older adults are more likely to get stomach ulcers and kidney problems from NSAIDs; doctors often prefer the gel form or the lowest effective dose.
• Use only as long as needed. For pain and inflammation, NSAIDs are generally meant for the shortest duration and lowest dose that works, as decided with your doctor.

Interactions (general)

Diclofenac can interact with blood-thinning medicines (like warfarin), increasing the risk of bleeding. It may also reduce the effect of blood pressure medicines and water tablets (diuretics), and can raise the levels of lithium and methotrexate in the blood. Combining it with alcohol or with corticosteroid tablets increases the chance of stomach ulcers. Tell your doctor about ALL the medicines you take — including herbal, ayurvedic and over-the-counter products — before starting diclofenac.

Pregnancy and breastfeeding (general guidance)

Diclofenac should be avoided in pregnancy, especially in the third trimester, when it can harm the baby's heart and kidneys and delay labour. If you are planning a pregnancy or are in the first two trimesters, consult your doctor first — there may be safer alternatives. Small amounts pass into breast milk, but it is generally considered compatible with breastfeeding at low doses; still, check with your doctor.

Storage

Store at room temperature in a dry place, away from direct sunlight and moisture. Keep tablets in their original pack until use, keep the tube of gel tightly closed, and keep all forms out of the reach of children. Do not use after the expiry date printed on the pack.

When to see a doctor

See a doctor if: pain does not improve after a few days of use, you develop stomach pain or black stools, you vomit blood, you notice swelling of the ankles or face, you get breathless or develop a rash, or you need the medicine for more than a few days. Seek emergency care for signs of stomach bleeding, chest pain, sudden weakness or numbness on one side, or swelling of the face, lips or tongue with difficulty breathing.

FAQs

1. Is diclofenac stronger than paracetamol?

They work differently. Diclofenac reduces inflammation as well as pain, so doctors often prefer it for joint pain, sprains and swelling. Paracetamol is usually gentler on the stomach. Which one suits you depends on the condition and your health, so ask your doctor or pharmacist.

2. Can I use diclofenac gel and tablets together?

Sometimes doctors prescribe both, but you should not do this on your own. Combining them raises the total amount of diclofenac in your body and increases the risk of side effects, especially stomach and kidney problems.

3. How long can I safely take diclofenac?

It is meant for short-term use in most pain conditions — the lowest dose for the shortest time that controls the pain. Long-term use needs a doctor's supervision because of the risks to the stomach, heart, blood pressure and kidneys.

4. Is the gel safer than the tablets?

For localised pain, the gel usually causes fewer body-wide side effects because less medicine enters the bloodstream. But it is not completely risk-free — it can irritate the skin, and some medicine is still absorbed. Use only the amount directed and do not apply it to broken skin.