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Subcutaneous NSAIDs in palliative care - diclofenac

Palliative care

Amber–for medicines normally initiated by a specialist but may be used by generalists.

Introduction

This guide is intended for use in primary and secondary care to support the management of patients receiving diclofenac for mild-to-moderate pain and inflammation. Diclofenac is a non-steroidal anti-inflammatory drug (NSAID).

Subcutaneous (SC) diclofenac should only be started under specialist palliative care guidance and patients require ongoing specialist supervision.

Description

Diclofenac is a preferential COX-2 inhibitor. It is frequently used for postoperative pain relief and musculoskeletal pain disorders. It is also used off label in the following indications: renal or biliary colic (injection), dysmenorrhoea and cancer pain and neoplastic fever.

Preparations

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Note: Administration via the subcutaneous (SC) route is off label

Injection Voltarol 25 mg/mL (3 mL ampoules)

ALKALINE PH: Do not mix in continuous subcutaneous infusion (CSCI) with other drugs.

DILUENT: 0.9 % sodium chloride.

Indications

  • Can be used for bone pain in cancer where standard therapies have been ineffective.
  • Off-label use when administered via the subcutaneous route.

Contraindications

  • Hypersensitivity to aspirin or other NSAIDs, active gastrointestinal (GI) ulceration or active bleeding event

Refer to Diclofenac sodium in the British National Formulary (BNF) or Voltarol ampoules on the Summary of Product Characteristics (SPC) for a full list of contraindications.

Cautions

Avoid in patients with significant cardiovascular risk factors, for example, cardiac events, myocardial infarction or cardiac failure. See BNF for a comprehensive list of cautions.

Liver impairment

  • Use caution in mild-to-moderate impairment.
  • Avoid in severe liver impairment.

Renal impairment

  • Avoid where possible. Monitor for fluid retention, worsening renal impairment and renal failure.
  • Manufacturer advises avoiding diclofenac sodium in patients with severe renal impairment.

Drug interactions:

  • There are several known interactions; refer to the BNF or SPC

Monitoring

  • Baseline and ongoing monitoring of renal function during use, if appropriate.
  • Monitor injection sites closely as subcutaneous injection can be an irritant. NOTE: Skin necrosis may occur very rarely.

Side effects

Reduced appetite, diarrhoea, dizziness, gastrointestinal discomfort, gastrointestinal disorders, headache, nausea, vertigo, vomiting. In the case of rash, discontinue.

Dose and administration

Two alternative regimens are recommended:

For the acute treatment of moderate to severe pain

  • 25–50 mg can be administered by SC or intramuscular (IM) bolus injection.
  • If necessary, treatment may be repeated after 4 to 6 hours, not exceeding 150 mg within any period of 24 hours.
  • Important: excipients make it an irritant as a SC bolus injection.

For the prevention and treatment of background pain

  • Consider if a loading dose of 25-50 mg by SC or IM bolus injection is needed, followed by
  • 75-150 mg/24 hours CSCI diluted with sodium chloride 0.9 %.

Discontinuing diclofenac

This may be needed if treatment is ineffective, the patient is experiencing side effects or a site reaction.

Routinely review after 2 days of administration to consider if discontinuation is appropriate or not.

Practice points

  • Important: diclofenac sodium is alkaline and is given alone via a separate syringe pump because of a lack of information on compatibility with other drugs.
  • Approximate oral to SC conversion factor is 1:1.
  • Onset of action is usually about 20–30 minutes.
  • Severe necrosis local to the injection site is possible with the injectable Voltarol© product given SC.
  • In patients at increased risk of NSAID-related upper gastrointestinal complications, diclofenac should be co-prescribed with a gastro-protective agent, such as a PPI, wherever possible.

References

British National Formulary (online) Diclofenac sodium | Drugs | BNF | NICE. Last accessed online 12/05/25.

Palliative Care Formulary. Diclofenac sodium. In: Palliative Care Formulary (PCF) [Internet]. London: Pharmaceutical Press; 2026 [cited 2026 Apr 1]. Available from: https://www.medicinescomplete.com [Link with NHS login (NB log in to PCF via knowledge network)]]

Voltarol ampoules SPC (online) Voltarol Ampoules - Summary of Product Characteristics (SmPC) - (emc) | 1043 Last accessed online 12/05/25