For sedation prior to anesthesia or procedures, for longer and/or more stimulating procedures, midazolam IM can be used to facilitate insertion of an IV catheter for titration of additional medication.
Midazolam IM doses of 0.1 to 0.15 mg/kg are usually effective and do not prolong emergence from general anesthesia. For more anxious patients, doses up to 0.5 mg/kg may be needed.
Midazolam IM and an opioid should not be mixed as a premedication; however, if required, then constant monitoring is recommended.
Should both be required, the initial dose of each must be reduced and the second agent of the two should be administered IV on arrival at the procedure area.
Midazolam IM is absorbed rapidly after intramuscular (0.1 to 0.15 mg/kg, maximum of 7.5 mg), oral (0.25 to 1.0 mg/kg, maximum of 20 mg), rectal (0.75 to 1.0 mg/kg, maximum of 20 mg), nasal (0.2 mg/kg), or sublingual (0.2 mg/kg) administration.
Many medications, such as methohexital (10 mg/kg), ketamine (2 to 10 mg/kg combined with atropine [0.02 mg/kg] and midazolam [0.5 mg/kg]), or midazolam alone (0.15 to 0.2 mg/kg), are administered intramuscularly for premedication or induction of anesthesia.
The main advantage of this route of administration is its reliability; its main disadvantage is that it is painful.
Benzodiazepines have limited allergenic effects and do not suppress the adrenal gland. The most significant problem with midazolam is respiratory depression.
The reversal of midazolam induced (0.13 mg/kg) respiratory depression with flumazenil (1 mg) lasts 3 to 30 minutes.