Paracetamol (IV)
Brand names: Perfalgan
Intravenous paracetamol is a non-opioid analgesic and antipyretic used perioperatively as a baseline component of multimodal analgesia and where the oral route is unavailable.
Adult dose
Paediatric dose
Dose adjustments
§4.2: 'Severe renal insufficiency: It is recommended, when giving paracetamol to patients with severe renal impairment (creatinine clearance <= 30 ml/min), to reduce the dose and increase the minimum interval between each administration to 6 hours.' 'The minimum interval between each administration in patients with severe renal insufficiency must be at least 6 hours.' §4.4 also lists severe renal insufficiency (creatinine clearance <= 30 ml/min) among the conditions requiring caution. No milligram reduction figure is given in the SPC.
'Cases of severe hepatocellular insufficiency' are an absolute contraindication (§4.3). §4.2: 'Adults with hepatocellular insufficiency, chronic alcoholism, chronic malnutrition (low reserves of hepatic glutathione), dehydration: The maximum daily dose must not exceed 3000 mg.' The posology table separately caps patients over 50 kg 'with additional risk factors for hepatotoxicity' at a maximum daily dose of 3 g (versus 4 g without such risk factors). §4.4 lists hepatocellular insufficiency, chronic alcoholism, chronic malnutrition and dehydration as cautions.
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 paracetamol, propacetamol hydrochloride (prodrug of paracetamol) or to any of the excipients listed in section 6.1
- Cases of severe hepatocellular insufficiency
Side effects
- Thrombocytopenia, leucopenia, neutropenia (very rare, <1/10,000)
- Hypersensitivity reaction (very rare) - 'ranging from simple skin rash or urticaria to anaphylactic shock have been reported and require discontinuation of treatment'
- High anion gap metabolic acidosis due to pyroglutamic acidosis (metabolism and nutrition disorders)
- Hypotension (rare); flushing (isolated cases)
- Tachycardia (isolated cases)
- Increased levels of hepatic transaminases (rare)
- Serious skin reactions (very rare); pruritus and erythema (isolated cases)
- Malaise (rare)
- Injection site reactions - 'Frequent adverse reactions at injection site have been reported during clinical trials (pain and burning sensation)'
- Liver damage with doses higher than recommended - 'fulminant hepatitis, hepatic failure, cholestatic hepatitis, cytolytic hepatitis ... usually first seen after two days of drug administration with a peak seen, usually after 4 - 6 days' (§4.4)
Monitoring
- 'In order to avoid the risk of overdose, check that other medicines administered do not contain either paracetamol or propacetamol' - the maximum daily dose in the posology table applies only to patients not receiving other paracetamol-containing products
- 'If HAGMA due to pyroglutamic acidosis is suspected, prompt discontinuation of paracetamol and close monitoring is recommended. The measurement of urinary 5-oxoproline may be useful to identify pyroglutamic acidosis as underlying cause of HAGMA in patients with multiple risk factors'
- 'close monitoring is needed notably at the end of the infusion, regardless of administration route ... particularly for central route infusions, in order to avoid air embolism'
- Watch for clinical signs and symptoms of liver damage, which are 'usually first seen after two days of drug administration with a peak seen, usually after 4 - 6 days'; 'Treatment with antidote should be given as soon as possible'
- Review the need for the IV route daily - 'Prolonged or frequent use is discouraged. It is recommended that a suitable analgesic oral treatment will be used as soon as this route of administration is possible'
Clinical monograph
How it works
Paracetamol produces analgesia and antipyresis through centrally mediated mechanisms, including effects on prostaglandin pathways and descending modulation, with minimal peripheral anti-inflammatory action.
Prescribing in practice
- Dose by body weight and reduce the dose in low body weight, malnutrition, hepatic impairment, chronic alcohol use or dehydration to avoid hepatotoxicity, and guard against accidental overdose by accounting for all paracetamol-containing products.
- Administer as a controlled infusion and double-check weight-based dosing, as intravenous administration bypasses first-pass metabolism and errors carry greater risk.
- It is opioid-sparing and combines well with NSAIDs and regional techniques as part of multimodal analgesia.
Monitoring
Routine monitoring is not required at therapeutic doses, but check liver function and consider toxicology if overdose or cumulative excess is suspected.
Counselling the patient
- This is a paracetamol drip given into a vein to help control pain and reduce reliance on stronger painkillers.
- Do not take additional paracetamol from other sources without telling staff.
Evidence & guidelines
Intravenous paracetamol is widely used and recommended as a foundation of opioid-sparing multimodal perioperative analgesia.
Reference: Perfalgan SPC; PROSPECT Guidelines; ERAS Society Guidelines; 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.
- Morphine Milligram Equivalents (MME) Calculator · Pain / Opioids
- Opioid Conversion / Equianalgesic Guide · Pain Management
- Rumack-Matthew Nomogram · Toxicology
- Numeric Rating Scale (NRS) Pain Assessment and Management · Pain Management
- King's College Criteria for Acute Liver Failure · Prognosis
- Kings College Criteria for Paracetamol Toxicity · Hepatology
- Major Trauma — Primary Survey (ATLS) · ATLS 10th Edition; JRCALC; NICE NG39
- Major Haemorrhage / Massive Transfusion · BCSH; RCOA; RCEM; RCS — BCSH Guidelines
- Burns — TBSA Estimation & Fluid Resuscitation · British Burn Association; EMSB; RCEM 2024
- Lower Gastrointestinal Bleed · NICE; BSG; ACPGBI — Commissioning Guide
- Acute Pancreatitis · NICE; IAP/APA; ACPGBI — CG104
- Hypertrophic Pyloric Stenosis · BAPS / RCPCH