Diclofenac — Uses, Dosage, Side Effects & Safety

Drug class: Nonsteroidal Anti-Inflammatory Drug (NSAID)

At a glance: Diclofenac is a nonsteroidal anti-inflammatory drug (NSAID) primarily utilized for pain management and the treatment of various inflammatory conditions. Its therapeutic action involves inhibiting cyclooxygenase enzymes, thereby reducing prostaglandin synthesis. Common side effects include gastrointestinal upset, and patients should be monitored for signs of renal impairment during prolonged use.

Overview

Diclofenac is a nonsteroidal anti-inflammatory drug (NSAID) used to relieve pain, swelling, and inflammation in conditions such as arthritis, muscle injuries, and menstrual cramps. It is also available in topical forms for localized pain relief, such as joint or muscle pain. Diclofenac works by blocking substances in the body (prostaglandins) that cause inflammation and pain. It can be taken orally, applied to the skin, or used as an injection or suppository, depending on the condition being treated. Key points: Use the lowest effective dose for the shortest possible time. Diclofenac may increase the risk of serious heart or stomach problems, especially with long-term use. Always follow your healthcare provider's instructions.

Clinical information

[{"title":"Mechanism of Action","content":"Diclofenac inhibits cyclooxygenase (COX-1 and COX-2) enzymes, reducing the synthesis of prostaglandins involved in inflammation, pain, and fever. This leads to decreased inflammation and analgesia. "},{"title":"Detailed Pharmacokinetics","content":"Absorption: Well absorbed orally; bioavailability ~50% due to first-pass metabolism. Distribution: Highly protein-bound (>99%). Metabolism: Extensively hepatic via CYP2C9. Elimination: Primarily renal (urine) as metabolites; half-life ~1–2 hours. "},{"title":"Clinical Contraindications & Precautions","content":"Contraindicated in patients with known hypersensitivity to diclofenac or other NSAIDs, active peptic ulcer disease, recent coronary artery bypass graft (CABG) surgery, severe hepatic or renal impairment, and history of NSAID-induced asthma or anaphylaxis. Use with caution in elderly, those with cardiovascular disease, hypertension, or gastrointestinal disorders. "},{"title":"Dose Adjustments","content":"Renal impairment: Use with caution; avoid in severe renal dysfunction. Hepatic impairment: Dose reduction may be necessary; avoid in severe hepatic disease. Elderly: Use lowest effective dose. Pediatric: Use only under specialist guidance. "},{"title":"Monitoring Parameters","content":"

Therapeutic uses

• Post-operative pain (select formulations)
• Inflammatory conditions
• Osteoarthritis and rheumatoid arthritis pain and inflammation
• Pain management
• Primary dysmenorrhea
• Ankylosing spondylitis
• Acute musculoskeletal injury

Common side effects

• Stomach pain
• Nausea
• Indigestion
• Diarrhea
• Heart attack
• Stroke
• Gastrointestinal bleeding
• Kidney problems

Drug interactions

• Reduces the antihypertensive effect of ACE inhibitors, ARBs, and diuretics
• Increased nephrotoxicity risk with other NSAIDs, ciclosporin, or tacrolimus
• Raises lithium and methotrexate blood levels
• Increases bleeding risk with anticoagulants and antiplatelet agents

Contraindications

• Use in the setting of coronary artery bypass graft surgery
• Third trimester of pregnancy
• Active gastrointestinal bleeding or peptic ulcer disease
• History of asthma, urticaria, or allergic reactions after taking aspirin or other NSAIDs
• Severe heart failure

Missed dose

If you miss a dose, take it as soon as you remember. If it is almost time for your next dose, skip the missed dose. Do not double up to make up for a missed dose.

Overdose

Symptoms of overdose may include severe stomach pain, vomiting, drowsiness, difficulty breathing, or seizures. Seek emergency medical attention or call your local poison control center immediately.

Storage

Store at room temperature away from moisture and heat. Keep out of reach of children.

Precautions & warnings

Carries an increased risk of serious cardiovascular thrombotic events and serious gastrointestinal bleeding, ulceration, and perforation, which can occur without warning. Use the lowest effective dose for the shortest duration necessary. Monitor blood pressure, renal function, and for signs of gastrointestinal bleeding.

Pregnancy

Avoid after 20 weeks of pregnancy due to risk of fetal renal dysfunction; contraindicated in the third trimester due to risk of premature closure of the ductus arteriosus.

Key safety information

• May cause gastrointestinal bleeding
• Risk of cardiovascular events with long-term use

Clinical Pearls

• May increase risk of heart attack or stroke, especially with long-term use.
• Can cause serious stomach or intestinal bleeding, ulcers, or perforation.
• Use with caution in patients with kidney or liver impairment.
• Not recommended during late pregnancy (third trimester).
• May cause severe skin reactions or allergic reactions.
• Avoid taking other NSAIDs (such as ibuprofen or naproxen) unless directed by your doctor.
• Avoid alcohol, as it increases the risk of stomach bleeding.
• Avoid driving or operating machinery if you feel dizzy or drowsy.

Frequently Asked Questions about Diclofenac

What conditions does diclofenac treat?

Diclofenac is used to relieve pain and inflammation in conditions such as osteoarthritis, rheumatoid arthritis, ankylosing spondylitis, acute musculoskeletal injuries, and menstrual pain. Topical forms are used for localized joint or muscle pain.

How quickly does diclofenac work?

Oral diclofenac usually begins to relieve pain within 30 to 60 minutes. Topical forms may take several days to achieve full effect.

Can I take diclofenac with other painkillers?

You can take diclofenac with acetaminophen (paracetamol), but avoid combining it with other NSAIDs (such as ibuprofen or naproxen) unless directed by your doctor.

Is diclofenac safe in pregnancy or breastfeeding?

Diclofenac is not recommended during the third trimester of pregnancy due to risk of fetal harm. Use during breastfeeding should be discussed with your healthcare provider.

What should I do if I develop stomach pain while taking diclofenac?

Stop taking diclofenac and contact your doctor immediately if you experience severe stomach pain, black or bloody stools, or vomiting blood.

Can diclofenac cause high blood pressure?

Yes, diclofenac and other NSAIDs may increase blood pressure or worsen existing hypertension. Regular monitoring is recommended.

How long can I safely use diclofenac?

Use diclofenac at the lowest effective dose for the shortest duration necessary. Long-term use increases the risk of serious side effects.

Educational information only. Always consult a qualified healthcare professional before starting, stopping, or changing any medication.