Midazolam

Source: UK SPC (eMC) for Midazolam 1 mg/ml solution for injection/infusion, §4.2 (https://www.medicines.org.uk/emc/product/13192/smpc). Midazolam is a potent sedative that requires slow administration and titration; it must not be given rapidly or as a bolus. Onset of action is approximately 2 minutes after injection, maximum effect at approximately 5 to 10 minutes. ELDERLY / DEBILITATED / CHRONICALLY ILL (conscious sedation): initial dose 0.5 to 1 mg IV 5 to 10 minutes before the procedure, additional 0.5 to 1 mg doses as necessary, titrated very slowly because peak effect takes longer; total dose < 3.5 mg. OTHER ADULT REGIMENS IN §4.2 — ANAESTHESIA PREMEDICATION (ASA I-II, under 60 years): 1 to 2 mg IV repeated as necessary, or 0.07 to 0.1 mg/kg IM (deep into the muscle mass, 20 to 60 minutes before induction); over 60 years/debilitated/chronically ill: 0.5 mg IV initially increased slowly as needed, or 0.025 to 0.05 mg/kg IM; with concomitant narcotics the midazolam dose should be reduced, usual dosage 2 to 3 mg. ANAESTHESIA INDUCTION: premedicated adults under 60 years 0.15 to 0.2 mg/kg IV (non-premedicated 0.3 to 0.35 mg/kg IV); each increment of not more than 5 mg injected over 20 to 30 seconds with 2-minute intervals; in refractory cases a total dosage of up to 0.6 mg/kg may be used but may prolong recovery; premedicated over 60 years/debilitated/chronically ill 0.05 to 0.15 mg/kg IV over 20 to 30 seconds; non-premedicated over 60 years 0.15 to 0.3 mg/kg; non-premedicated debilitated or severe systemic disease 0.15 to 0.25 mg/kg. If used before or with other induction agents, the initial doses of all of them should be significantly reduced, sometimes to as low as 25% of the usual initial dose. SEDATIVE COMPONENT IN COMBINED ANAESTHESIA: intermittent IV doses of 0.03 to 0.1 mg/kg, or continuous IV infusion of 0.03 to 0.1 mg/kg/h, typically with analgesics; lower doses in adults over 60 years/debilitated/chronically ill. SEDATION IN THE INTENSIVE CARE UNIT (adults): IV loading dose 0.03 to 0.3 mg/kg given slowly in increments — each 1 to 2.5 mg dose over 20 to 30 seconds with 2-minute intervals; IV maintenance dose 0.03 to 0.2 mg/kg/h. Reduce or omit the loading dose and reduce the maintenance dose in hypovolaemia, vasoconstriction or hypothermia. If given with strong analgesics, give the analgesic first. Long-term sedation may lead to tolerance requiring dose increase. HEPATIC IMPAIRMENT: hepatic impairment reduces clearance and increases terminal half-life, which may lead to a stronger and prolonged clinical effect; the required dose may be reduced and vital signs should be properly monitored. NOTE ON ROUTES: this SPC covers intravenous, intramuscular and rectal use only — it contains NO buccal (oromucosal) or intranasal regimen, so any buccal/intranasal seizure dosing must be sourced separately. In children weighing less than 15 kg, midazolam solutions with a concentration higher than 1 mg/ml are not recommended; higher concentrations should be diluted to 1 mg/ml.

Anchored on the CONSCIOUS SEDATION intravenous regimen in §4.2 of the UK SPC (Midazolam 1 mg/ml solution for injection/infusion). Other paediatric regimens stated in the SAME §4.2, which are NOT interchangeable with the above — CONSCIOUS SEDATION: not recommended in children under 6 months (especially predisposed to airway obstruction and hypoventilation); children 12 to 16 years use the adult dosages; rectal 0.3 to 0.5 mg/kg total dose (not recommended under 6 months; give the whole dose at once, avoid repeated rectal administration); intramuscular 0.05 to 0.15 mg/kg (total dose greater than 10.0 mg usually not required; IM only in exceptional cases as it is painful — rectal preferred). ANAESTHESIA PREMEDICATION (children over 6 months): rectal 0.3 to 0.5 mg/kg 15 to 30 minutes before induction; intramuscular 0.08 to 0.2 mg/kg; not recommended in children under 6 months. ICU SEDATION: neonates born before 32 weeks gestation — continuous IV infusion 0.03 mg/kg/h (0.5 micrograms/kg/min); neonates born after 32 weeks gestation and children up to 6 months — continuous IV infusion 0.06 mg/kg/h (1 microgram/kg/min); IV loading doses are NOT recommended in preterm infants, neonates and children up to 6 months (instead run a higher infusion rate during the first hours). Children over 6 months, intubated and ventilated — IV loading dose 0.05 to 0.2 mg/kg slowly over 2 to 3 minutes, then continuous infusion 0.06 to 0.12 mg/kg/h (1 to 2 micrograms/kg/min), adjusted generally by 25% of the initial or following infusion rate. Infants and children under 5 years may require significantly higher mg/kg doses than older children and adolescents. Convulsions have been reported in premature infants and neonates. In premature infants, neonates and children under 15 kg, solutions more concentrated than 1 mg/ml are not recommended. Verify all paediatric dosing against a children's formulary before use.