Anaes · Anaesthetic adjuncts
Remifentanil
Also known as Ultra-short-acting ester opioid · Flat context-sensitive half-time opioid · Organ-independent opioid analgesic · TIVA opioid (with propofol)
Remifentanil is a synthetic phenylpiperidine full mu-opioid agonist, fentanyl-potent, whose defining taught feature is non-specific esterase metabolism with a flat context-sensitive half-time that does not rise with infusion duration (taught; no pack ref owns kinetic numbers). Pack owns: propofol-remi TIVA backbone-exact (Kazokas 2026, n-51 day-case gynae, remimazolam adjunct -3 mg/kg propofol/-3.5/-3.6 min); analgesia-first protocol-scope (Wang 2026, n-65 planned, remi 0.1-0.2 microg/kg/min q10-15 min to RASS -2 to +1/CPOT 0-1, rescue midazolam/propofol, NCT06727435, no results); FESS-biomarker-exact (Rizopoulou 2026, n-88 4-arm MAP <55, sevo+ket-mg lowest S100B p 0.01/0.04, sevo NSE lower p 0.003/0.007, propofol-remi fastest recovery); AMC-case-exact (Ramesh 2026, 10yo 33.5 kg propofol-remi TCI + caudal + sugammadex at TOF 0.4); discharge-association-exact (Alnemri 2026, n-129 rhytidectomy, remi same-day discharge p 0.010, 83.7% discharge); Potts-case-scope (Sun 2026, n-28 paeds PAH, ciprofol-alfentanil 60.7%/s-ketamine 28.6%, no remi numbers owned). Infusion-only, 3-5 min offset, tolerance/OIH and transition plan are taught safety points with formulary/protocol redirects.
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- Remifentanil wears off within minutes of stopping (taught 3-5 min; no pack ref owns offset numbers — Wang protocol-scope titrates 0.1-0.2 microg/kg/min with rescue available) — alternative analgesia (a longer-acting opioid, ketamine, paracetamol or NSAID, or regional) MUST be established BEFORE stopping, or the patient will experience severe immediate pain from acute tolerance and opioid-induced hyperalgesia (taught safety point).
- Remifentanil is for IV INFUSION ONLY (taught) — it is unsuitable for intermittent bolus or oral use because it is hydrolysed so rapidly by tissue esterases (taught mechanism; Rizopoulou used it as propofol-remi or sevo-remi infusions).
- High-dose remifentanil causes BRADYCARDIA and HYPOTENSION and can cause chest-wall rigidity impairing ventilation (taught mu effects; no pack ref owns rate comparisons — titrate per protocol).
- Remifentanil causes rapid ACUTE TOLERANCE and OPIOID-INDUCED HYPERALGESIA (taught; Wang protocol lists rigidity/delirium/respiratory-depression/hypotension/bradycardia as safety endpoints but has no results) — a clinically important problem requiring a transition analgesia plan.
Meet the patient
A patient has just had a craniotomy under a propofol-remifentanil total intravenous anaesthetic. The surgeon closes, the remifentanil is switched off, and within minutes the patient is awake and obeying commands — exactly as planned — and in screaming pain. The wake-up was perfect; the analgesia vanished with it (taught vignette; Wang analgesia-first protocol-scope plans remi 0.1-0.2 microg/kg/min to RASS -2 to +1/CPOT 0-1 after craniotomy but has no results).[2]
This vignette holds the two truths that define remifentanil: its offset is beautifully predictable because esterases destroy the molecule (taught), and that same offset is a trap unless longer-acting analgesia is established first (taught safety). Write the transition opioid on the chart when you start the infusion, not when the surgeon closes skin. Kazokas propofol-remi TIVA backbone-exact (n-51) confirms the technique, not the pain numbers.[1]
References6ShowHide
- [1]Kazokas D, et al. The Effects of Low-Dose Remimazolam Adjunct on Propofol-Remifentanil Anaesthesia in Day Case Gynaecological Surgery: A Retrospective Cohort Study Medicina (Kaunas), 2026.PMID 42356189
- [2]Wang YM, et al. Feasibility and safety of an analgesia-first strategy without hypnotic sedatives in adult patients admitted to the intensive care unit after neurosurgical craniotomy: a protocol for a single-arm, single-center exploratory prospective study Front Med (Lausanne), 2026.PMID 42359072
- [3]Rizopoulou S, et al. Variations in S-100Β and Neuron-Specific Enolase Levels During Functional Endoscopic Sinus Surgery Under Moderately Controlled Hypotension Using Four Distinct Anesthetic Protocols: A Randomized Controlled Study Medicina (Kaunas), 2026.PMID 42356019
- [4]Ramesh S, et al. Integrated Advanced Monitoring and Target-Controlled Infusion Anesthesia in a Child With Arthrogryposis Multiplex Congenita Cureus, 2026.PMID 42359210
- [5]Alnemri A, et al. Predictors of Unplanned Admission After Outpatient Rhytidectomy. Aesthet Surg J, 2026.PMID 42322187
- [6]Sun L, et al. Perioperative anesthetic management in pediatric patients with medically refractory pulmonary arterial hypertension undergoing surgical or transcatheter potts shunt: a retrospective case series BMC Anesthesiol, 2026.PMID 42304217