Adults

Premedication (IM): 0.07-0.08 mg/kg (approx. 5 mg for average adult) 30-60 min before procedure. Conscious sedation (IV): Initial 0.02-0.04 mg/kg slowly, titrated to effect. Induction of anesthesia (IV): 0.3-0.35 mg/kg. Long-term sedation (IV infusion): 0.03-0.2 mg/kg/hr.

Elderly

Reduced dosage required. Initial IV dose for conscious sedation should be 0.01-0.02 mg/kg and titrated carefully due to increased sensitivity and slower elimination.

Renal_impairment

Use with caution. Dosage reduction may be necessary, especially for long-term infusions, as metabolites may accumulate.

Onset

Intravenous: 1-5 minutes for sedation; Intramuscular: 5-15 minutes for sedation.

Excretion

The metabolites are mainly excreted via the kidneys (urine), largely as glucuronide conjugates.

Half life

Terminal elimination half-life is typically 1.5-3.5 hours, but can be prolonged in elderly or critically ill patients.

Absorption

Rapidly absorbed after intramuscular administration, with peak plasma concentrations reached within 15-30 minutes. Following intravenous administration, it has a rapid onset due to high lipophilicity and rapid distribution.

Metabolism

Extensively metabolized in the liver, primarily by cytochrome P450 3A4 (CYP3A4) to its active metabolite, 1-hydroxymidazolam.

Opioids

Potentiates central nervous system and respiratory depressant effects, increasing risk of sedation, respiratory depression, coma, and death.

CYP3A4 Inducers (e.g., rifampicin, carbamazepine)

Decrease midazolam plasma concentration and shorten its effects, potentially reducing efficacy.

CYP3A4 Inhibitors (e.g., ketoconazole, erythromycin)

Significantly increase midazolam plasma concentration and prolong its effects, requiring dosage reduction.