Dexmedetomidine

THE INFUSION RATE IS PER HOUR (micrograms/kg/h), NOT per minute — the SPC explicitly states 'Dexmedetomidine is very potent and the infusion rate is given per hour.' For less invasive procedures such as ophthalmic surgery, a loading infusion of 0.5 micrograms/kg given over 10 minutes may be suitable. Depending on the procedure, concomitant local anaesthesia or analgesia may be needed; additional analgesia or sedatives (e.g. opioids, midazolam or propofol) are recommended for painful procedures or if increased depth of sedation is necessary. The pharmacokinetic distribution half-life is estimated at around 6 minutes, which can be taken into account when assessing the time needed for titration. ICU SEDATION OF ADULTS (sedation level not deeper than arousal in response to verbal stimulation, RASS 0 to -3): patients already intubated and sedated may switch to dexmedetomidine with an initial infusion rate of 0.7 micrograms/kg/h, adjusted stepwise within the dose range 0.2 to 1.4 micrograms/kg/h; a lower starting infusion rate should be considered for frail patients; after dose adjustment a new steady-state sedation level may not be reached for up to one hour; use of a LOADING DOSE in ICU sedation is NOT recommended and is associated with increased adverse reactions (propofol or midazolam may be given if needed until the clinical effects of dexmedetomidine are established). DURATION: there is no experience of use for more than 14 days; use beyond this should be regularly reassessed. (The US label separately states that administration duration should not exceed 24 hours.) MONITORING: all patients should have continuous cardiac monitoring during infusion, and respiration should be monitored in non-intubated patients due to the risk of respiratory depression and in some cases apnoea; supplemental oxygen should be immediately available and oxygen saturation monitored by pulse oximetry; during conscious sedation patients should be continuously monitored by persons not involved in the conduct of the procedure. Time to recovery is approximately one hour; in an outpatient setting, close monitoring should continue for at least one hour (or longer based on the patient's condition), with medical supervision continued for at least one further hour. CAUTIONS: should not be used as a general anaesthetic induction agent for intubation or to provide sedation during muscle relaxant use; not suitable for patients requiring continuous deep sedation; lacks anticonvulsant action; not recommended for patient-controlled sedation. ELDERLY: no dose adjustment is normally required, but elderly patients appear to have an increased risk of hypotension, and §4.4 states that patients over 65 years may be more prone to hypotension with dexmedetomidine, including a loading dose for procedures, so a dose reduction should be considered. HEPATIC IMPAIRMENT: dexmedetomidine is metabolised in the liver and should be used with caution — a reduced maintenance dose may be considered. PAEDIATRIC: 'The safety and efficacy of Dexdor in children aged 0 to 18 years have not been established... no recommendation on a posology can be made' — so paedDose is null. PROVENANCE NOTE: the interactions listed come from the US label section 7 (openFDA) plus the UK SPC §4.4 statement on combining with other sedative or cardiovascular agents, because no UK SPC §4.5 was present in the fetched bundle.