Diclofenac

How it works

It inhibits cyclo-oxygenase (COX-1 and COX-2), reducing prostaglandin synthesis and thereby decreasing inflammation, pain and fever.

Prescribing in practice

• In older patients the cardiovascular, gastrointestinal bleeding and renal risks are amplified; diclofenac carries a relatively high cardiovascular risk and is generally avoided, with the lowest effective dose for the shortest time if used and gastroprotection considered.
• Avoid or use great caution with concurrent anticoagulants, antiplatelets, ACE inhibitors/ARBs, diuretics and other NSAIDs, and in heart failure, peptic ulcer disease or significant renal impairment.
• It is contraindicated in established ischaemic heart disease, cerebrovascular disease, peripheral arterial disease and heart failure.

Monitoring

Monitor renal function and blood pressure, and watch for gastrointestinal and cardiovascular symptoms, especially in dehydrated or polypharmacy patients.

Counselling the patient

• Take with or after food and report any black stools, vomiting blood or indigestion promptly.
• Do not combine with other anti-inflammatory painkillers, including over-the-counter ones.
• Use for the shortest time needed and report ankle swelling, breathlessness or reduced urine output.

Evidence & guidelines

MHRA advice and large cardiovascular safety reviews confirm diclofenac carries an elevated thrombotic risk comparable to some COX-2 inhibitors, supporting restricted use in older and at-risk patients.