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NSAID — Renal / Ureteric Colic Pregnancy: Inhibition of prostaglandin synthesis may adversely affect the pregnancy and/or the embryo/foetal development. Epidemiological data suggest an increased risk of miscarriage and of cardiac malformation and gastroschisis after use of a prostaglandin synthesis inhibitor in early pregnancy; the absolute risk for cardiovascular malformation was increased from less than 1% up to approximately 1.5%, and is believed to increase with dose and duration of therapy. From the 20th week of pregnancy onward, Voltarol use may cause oligohydramnios resulting from foetal renal dysfunction, and ductus arteriosus constriction has been reported following treatment in the second trimester. During the first and second trimester, Voltarol should not be given unless clearly necessary; if used by a woman attempting to conceive, or in the first or second trimester, the dose should be kept as low and the duration as short as possible. Antenatal monitoring for oligohydramnios and ductus arteriosus constriction should be considered after exposure for several days from gestational week 20 onward, and Voltarol discontinued if either is found. During the third trimester all prostaglandin synthesis inhibitors may expose the foetus to cardiopulmonary toxicity and renal dysfunction, and the mother and neonate to possible prolongation of bleeding time and inhibition of uterine contractions resulting in delayed or prolonged labour. Consequently Voltarol is contraindicated during the third trimester. Lactation: diclofenac passes into breast milk in small amounts and should not be administered during breast feeding. Fertility: the use of diclofenac may impair female fertility and is not recommended in women attempting to conceive; withdrawal should be considered in women who have difficulty conceiving or are undergoing investigation of infertility. (Section 4.6 text is truncated at source after this point.)

Diclofenac

Brand names: Voltarol, Dyloject (IV)

Diclofenac is a non-steroidal anti-inflammatory drug; in urology it is widely used for the acute pain of renal or ureteric colic, where NSAIDs are first-line analgesia. It is available by oral, rectal, and parenteral routes.

Adult dose

Dose: Renal colic: one 75 mg ampoule intramuscularly (deep intragluteal injection into the upper outer quadrant)
Route: Intramuscular
Frequency: Single dose; a further ampoule may be administered after 30 minutes if necessary
Max: 150 mg daily (SPC: 'The recommended maximum daily dose of Voltarol is 150mg')
The pinned product, Voltarol Ampoules (eMC product 1043), is licensed in section 4.1 for IM use in 'acute forms of pain, including renal colic', so the indication matches. ROUTES THIS CARD DOES NOT COVER: the page also lists intravenous and rectal routes. Rectal diclofenac is not in this SPC. The SPC licenses intravenous infusion ONLY 'for treatment or prevention of post-operative pain in the hospital setting', not for renal colic, so no IV dose is given here; the SPC states 'Voltarol must not be given as an intravenous bolus injection'. Duration: SPC 4.2 - 'Voltarol ampoules (given im or iv) should not be given for more than two days; if necessary, treatment can be continued with Voltarol tablets or suppositories.' Injection technique: the SPC says the directions for intramuscular injection 'must be adhered to in order to avoid damage to a nerve or other tissue at the injection site'; if two injections daily are required, use the alternative buttock for the second. Undesirable effects may be minimised by using the lowest effective dose for the shortest duration necessary to control symptoms. Elderly: use with particular caution; the lowest effective dosage is recommended in frail elderly patients or those with a low body weight, and monitor for GI bleeding. Cardiovascular: contraindicated in established congestive heart failure (NYHA II-IV), ischaemic heart disease, peripheral arterial disease and/or cerebrovascular disease; patients with NYHA I heart failure or significant cardiovascular risk factors only after careful consideration. Renal failure is a contraindication (see renalAdjustment). Paediatric: 'Voltarol ampoules are not recommended for use in children.'

Dose adjustments

Renal

Contraindicated in renal failure (SPC 4.2/4.3). 'No specific studies have been carried out in patients with renal impairment, therefore, no specific dose adjustment recommendations can be made. Caution is advised when administering diclofenac to patients with mild to moderate renal impairment.' For intravenous use specifically (not this card's route), moderate or severe renal impairment (serum creatinine >160 µmol/l) and hypovolaemia or dehydration from any cause are also contraindications (SPC 4.3). SPC 4.4: particular caution in patients with impaired cardiac or renal function, hypertension, the elderly, those on diuretics or medicinal products that can significantly impact renal function, and those with substantial extracellular volume depletion from any cause; monitoring of renal function is recommended in such cases.

Hepatic

Contraindicated in hepatic failure (SPC 4.2/4.3). 'No specific studies have been carried out in patients with hepatic impairment, therefore, no specific dose adjustment recommendations can be made. Caution is advised when administering diclofenac to patients with mild to moderate hepatic impairment.' SPC 4.4: close medical surveillance is required in patients with impaired hepatic function; caution in hepatic porphyria, which it may trigger.

Dose independently re-sourced from UK Summary of Product Characteristics (SPC) via the eMC; US FDA prescribing information (openFDA / DailyMed) — cross-check; US labelling may differ from UK — clinician-reviewed. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

  • Hypersensitivity to the active substance, sodium metabisulphite or any of the excipients
  • Active gastric or intestinal ulcer, bleeding or perforation
  • History of gastrointestinal bleeding or perforation relating to previous NSAID therapy
  • Active, or history of recurrent, peptic ulcer/haemorrhage (two or more distinct episodes of proven ulceration or bleeding)
  • Last trimester of pregnancy
  • Hepatic failure
  • Renal failure
  • Established congestive heart failure (NYHA II-IV), ischaemic heart disease, peripheral arterial disease and/or cerebrovascular disease
  • Patients in whom attacks of asthma, angioedema, urticaria or acute rhinitis are precipitated by ibuprofen, acetylsalicylic acid or other NSAIDs
  • Specifically for intravenous use (not this card's route): concomitant NSAID or anticoagulant use (including low dose heparin); history of haemorrhagic diathesis or confirmed/suspected cerebrovascular bleeding; operations associated with a high risk of haemorrhage; a history of asthma; moderate or severe renal impairment (serum creatinine >160 µmol/l); hypovolaemia or dehydration from any cause

Side effects

  • Common: headache, dizziness, vertigo
  • Common: nausea, vomiting, diarrhoea, dyspepsia, abdominal pain, flatulence, anorexia
  • Common: transaminases increased; rash
  • Rare: hypersensitivity, anaphylactic and anaphylactoid reactions (including hypotension and shock); urticaria; asthma (including dyspnoea); hepatitis, jaundice, liver disorder; somnolence, tiredness
  • Gastrointestinal haemorrhage, haematemesis, melaena and gastrointestinal ulcer with or without bleeding or perforation (sometimes fatal, particularly in the elderly)
  • Uncommon (cardiac): myocardial infarction, cardiac failure, palpitations, chest pain; Kounis syndrome (not known)
  • Injection site abscess (very rare); injection site necrosis (not known); the SPC 4.4 also warns that incorrect intramuscular injection may cause muscle weakness, muscle paralysis, hypoaesthesia and embolia cutis medicamentosa (Nicolau syndrome)
  • Very rare: thrombocytopenia, leucopoenia, anaemia (including haemolytic and aplastic), agranulocytosis; angioneurotic oedema; hypertension, hypotension, vasculitis; fulminant hepatitis, hepatic necrosis, hepatic failure
  • Very rare: Stevens-Johnson syndrome, toxic epidermal necrolysis, bullous eruptions, exfoliative dermatitis; acute renal failure, haematuria, proteinuria, nephrotic syndrome

Interactions

  • Concomitant use with systemic NSAIDs, including cyclooxygenase-2 selective inhibitors, should be avoided (no evidence of synergistic benefit; additive undesirable effects)
  • Caution with medications that increase the risk of ulceration or bleeding: systemic corticosteroids, anticoagulants such as warfarin, SSRIs, anti-platelet agents such as acetylsalicylic acid
  • Combination therapy with a protective agent (e.g. misoprostol or a proton pump inhibitor) should be considered for patients with a history of ulcer, the elderly, and those needing concomitant low dose aspirin or medicinal products likely to increase gastrointestinal risk
  • Diuretics and medicinal products that can significantly impact renal function: particular caution; monitor renal function
  • For intravenous use specifically: concomitant NSAID or anticoagulant use (including low dose heparin) is contraindicated

Monitoring

  • Monitor for GI bleeding during NSAID therapy, particularly in the elderly; withdraw the drug if gastrointestinal bleeding or ulceration occurs
  • Close medical surveillance in patients with symptoms of gastrointestinal disorders or a history of gastric/intestinal ulceration, bleeding or perforation, and in ulcerative colitis or Crohn's disease
  • Monitoring of renal function is recommended in patients with impaired cardiac or renal function, hypertension, the elderly, those on diuretics, and those with extracellular volume depletion
  • Regular monitoring of hepatic function during prolonged treatment; discontinue if abnormal liver function tests persist or worsen or clinical signs of liver disease develop
  • Follow the intramuscular injection instructions strictly (deep intragluteal injection, upper outer quadrant, alternate buttock for a second daily injection) to avoid nerve or tissue damage and injection site necrosis
  • Be alert to hypersensitivity reactions, which can progress to Kounis syndrome (chest pain with an allergic reaction)

Clinical monograph

How it works

It inhibits cyclo-oxygenase (COX-1 and COX-2), reducing prostaglandin synthesis, which relieves pain and, in ureteric colic, lowers intraureteric pressure and renal pelvic pressure.

Prescribing in practice

  • Avoid in significant renal impairment, hypovolaemia, or dehydration because NSAIDs can precipitate acute kidney injury in the obstructed or volume-depleted patient.
  • It carries gastrointestinal bleeding and cardiovascular thrombotic risks and is contraindicated in established cardiovascular disease, so use the lowest effective course.
  • Use with caution alongside anticoagulants, other NSAIDs, and drugs affecting renal perfusion per the SPC.

Monitoring

Monitor renal function and blood pressure with repeated or prolonged use and remain alert to gastrointestinal symptoms.

Counselling the patient

  • Take with or after food to reduce stomach upset.
  • Report black stools, vomiting blood, or significant indigestion promptly.
  • Use for the shortest time needed to control colic pain.

Evidence & guidelines

Recommended as first-line analgesia for renal colic on the basis of trials showing NSAIDs provide effective pain relief with less need for rescue analgesia than opioids.

Reference: RCEM Clinical Standards for Emergency Analgesia; EAU Urolithiasis Guidelines 2024; MHRA 2013; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Related

Curated clinical cross-links plus same-class fallbacks.

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