Remifentanil

ALL RATES ARE MICROGRAMS/KG/MINUTE (not per hour). If endotracheal intubation is to occur more than 8 to 10 minutes after the start of the remifentanil infusion, an induction bolus is not necessary. Remifentanil is contraindicated as the sole agent for induction of anaesthesia and must be given with a standard dose of a hypnotic (propofol, thiopental or isoflurane). SPONTANEOUSLY BREATHING ANAESTHETISED PATIENTS WITH A SECURED AIRWAY (e.g. laryngeal mask): recommended starting infusion rate for supplemental analgesia 0.04 micrograms/kg/min, titrated to effect; rates from 0.025 to 0.1 micrograms/kg/min have been studied; bolus injections are NOT recommended in these patients; respiratory depression is likely to occur and ventilatory support and/or urgent intubation may be required. Remifentanil should not be used as an analgesic in procedures where patients remain conscious or do not receive any airway support. IMMEDIATE POST-OPERATIVE PERIOD in patients breathing spontaneously: decrease the infusion rate initially to 0.1 micrograms/kg/min, then increase or decrease by no more than 0.025 micrograms/kg/min every five minutes to balance analgesia and respiratory rate; bolus injections to treat post-operative pain are not recommended in spontaneously breathing patients. TARGET-CONTROLLED INFUSION (TCI, adults, ventilated): target blood remifentanil concentrations of 3 to 8 nanograms/mL generally give adequate analgesia for induction and surgery, with up to 15 nanograms/mL for particularly stimulating procedures; spontaneous respiration is likely to return at calculated concentrations around 1 to 2 nanograms/mL; TCI is not recommended for spontaneous-ventilation anaesthesia or for post-operative analgesia. CARDIAC ANAESTHESIA: after a hypnotic has produced loss of consciousness, remifentanil should be given at an initial infusion rate of 1 microgram/kg/min; bolus injections during induction in cardiac surgical patients are not recommended; endotracheal intubation should not occur until at least 5 minutes after the start of the infusion; high-risk cardiac patients (poor ventricular function, valve surgery) should be given a MAXIMUM bolus dose of 0.5 micrograms/kg; the same recommendations apply during hypothermic cardiopulmonary bypass. CAUTION: the cardiac-anaesthesia dosing TABLE did not extract cleanly from the source text (its bolus and infusion columns are ambiguous in the fetched material) — read that table directly in the SPC before using cardiac maintenance figures. DILUTION: for manually-controlled infusion, dilute to 20 to 250 micrograms/mL (50 micrograms/mL is the recommended dilution for adults); for TCI the recommended dilution is 20 to 50 micrograms/mL. CONCOMITANT MEDICATION: remifentanil significantly reduces the amount of hypnotic required — doses of isoflurane, thiopentone, propofol and temazepam have been reduced by up to 75% when used concurrently. DISCONTINUATION: no residual opioid activity will be present within 5 to 10 minutes after stopping, so longer-acting analgesia must be established before discontinuation; clear IV lines and cannulae to avoid inadvertent administration of residual remifentanil. INTENSIVE CARE: use in mechanically ventilated ICU patients is not recommended for a duration of treatment greater than 3 days. No absolute maximum dose is stated in the SPC, so maxDose is omitted. PROVENANCE NOTE: the interactions listed come from the US label section 7 (openFDA) plus the UK SPC §4.4 statement on concomitant sedatives, because no UK SPC §4.5 was present in the fetched bundle.

MAINTENANCE OF ANAESTHESIA ONLY. Induction of anaesthesia with remifentanil is NOT recommended in patients aged 1 to 12 years (no data available), and remifentanil is NOT recommended at all in neonates/infants aged under 1 year (insufficient clinical data). Co-administration of remifentanil with an intravenous anaesthetic agent for induction has not been studied in detail and is not recommended. TCI has not been studied in paediatric patients and is not recommended. CONTINUOUS INFUSION RATES ARE MICROGRAMS/KG/MINUTE. SPC dosing table for paediatric patients 1 to 12 years, each co-administered with nitrous oxide/oxygen in a ratio of 2:1: halothane (starting dose 0.3 MAC) — bolus 1 microgram/kg, infusion starting rate 0.25 micrograms/kg/min, range 0.05 to 1.3; sevoflurane (starting dose 0.3 MAC) — bolus 1 microgram/kg, infusion starting rate 0.25 micrograms/kg/min, range 0.05 to 0.9; isoflurane (starting dose 0.5 MAC) — bolus 1 microgram/kg, infusion starting rate 0.25 micrograms/kg/min, range 0.06 to 0.9. For sole administration of nitrous oxide (70%) with remifentanil, typical maintenance infusion rates should be between 0.4 and 3 micrograms/kg/min; although not specifically studied, adult data suggest 0.4 micrograms/kg/min is an appropriate starting rate. Surgery should not commence until at least 5 minutes after the start of the remifentanil infusion if a simultaneous bolus dose has not been given. Paediatric patients should be monitored and the dose titrated to the depth of analgesia appropriate for the surgical procedure. Recommended dilution for paediatric patients aged 1 year and over is 20 to 25 micrograms/mL. No paediatric maximum dose is stated in this SPC. Verify all under-18 dosing against a children's formulary before administration.