Opioid (Ultra-Short-Acting) Pregnancy: No adequate well-controlled studies; use in pregnancy only if potential benefit justifies potential risk to the foetus. Insufficient data for labour/Caesarean section. Discontinue breastfeeding for 24 hours after administration.

Remifentanil

Brand names: Ultiva

Remifentanil is an ultra-short-acting synthetic opioid used for analgesia during anaesthesia and for sedated, ventilated patients in intensive care.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: Induction of anaesthesia: 0.5-1 microgram/kg/min IV infusion, with or without an initial bolus of 1 microgram/kg given over not less than 30 seconds. Maintenance (ventilated patients): continuous infusion, starting 0.25-0.4 microgram/kg/min (range 0.05-2 microgram/kg/min), with bolus 0.5-1 microgram/kg

Route: Intravenous infusion (IV use only — must NOT be given epidurally or intrathecally)

Frequency: Continuous infusion by calibrated device, titrated in 25-100% increments / 25-50% decrements every 2-5 minutes

Must be individualised to patient response; not for use as the sole agent for induction. May be given by target-controlled infusion (TCI) using the Minto model (age and lean body mass). Maintenance starting rates depend on co-agent: nitrous oxide 66% -> 0.4; isoflurane 0.5 MAC -> 0.25; propofol -> 0.25 microgram/kg/min. Spontaneously breathing anaesthetised patients (secured airway): start 0.04 microgram/kg/min (range 0.025-0.1), no boluses. Elderly (>65 y): reduce starting dose by 50% (US label). Use in mechanically ventilated ICU patients not recommended for longer than 3 days. Reduces required doses of inhaled anaesthetics/hypnotics/benzodiazepines by up to 75%.

Dose auto-extracted from UK Summary of Product Characteristics (SPC) via the eMC; US FDA prescribing information (openFDA / DailyMed) — cross-check; US labelling may differ from UK — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

Epidural and intrathecal administration (glycine in formulation)
Hypersensitivity to remifentanil, other fentanyl analogues, or any excipient
Use as the sole agent for induction of anaesthesia

Side effects

Skeletal muscle rigidity (very common)
Hypotension (very common)
Nausea, vomiting (very common)
Bradycardia (common)
Acute respiratory depression, apnoea (common)

Interactions

Benzodiazepines and other CNS depressants (including alcohol, other opioids, general anaesthetics): additive risk of hypotension, respiratory depression, profound sedation, coma and death
Inhaled anaesthetics, hypnotics and benzodiazepines: remifentanil reduces their required doses (isoflurane, thiopentone, propofol, temazepam reduced by up to 75%)
Serotonergic drugs (SSRIs, SNRIs): risk of serotonin syndrome

Clinical monograph

How it works

It is a potent selective mu-opioid receptor agonist; its ester structure is rapidly broken down by non-specific blood and tissue esterases, giving a very short context-insensitive half-life.

Prescribing in practice

It causes dose-dependent respiratory depression and apnoea and must be given only by infusion with airway, ventilation and resuscitation support immediately available.
Because its effect dissipates within minutes of stopping, alternative analgesia must be planned before the infusion ends to avoid severe rebound pain.
It commonly causes bradycardia, hypotension and muscle rigidity, and its metabolism is independent of hepatic and renal function.

Monitoring

Continuous monitoring of respiration, oxygenation, heart rate and blood pressure is essential throughout the infusion.

Counselling the patient

This is a very short-acting opioid given by trained anaesthetic or critical-care staff.
Ensure ongoing pain relief is arranged before the infusion is discontinued.

Evidence & guidelines

Its pharmacology and use as an infusion-only opioid in anaesthesia and critical care are well established and described in the SPC.

Reference: Miller's Anesthesia; AAGBI TCI 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).

Curated clinical cross-links plus same-class fallbacks.

Calculators

Pathways