From the Guidelines
Midazolam is a short-acting benzodiazepine medication commonly used for sedation, anxiety relief, and as a premedication before medical procedures. It works by enhancing the effect of gamma-aminobutyric acid (GABA), a neurotransmitter that inhibits brain activity, resulting in sedation, muscle relaxation, and amnesia. Midazolam is available in various forms including injectable solutions (typically 1-5 mg IV for adults, adjusted based on age and health status), oral solutions, and tablets. The onset of action is rapid, usually within 1-5 minutes when given intravenously, with effects lasting 1-6 hours depending on the dose and route of administration.
Key Characteristics of Midazolam
- Onset of action: 1-5 minutes when given intravenously
- Duration of action: 1-6 hours depending on the dose and route of administration
- Common side effects: drowsiness, decreased breathing, and lowered blood pressure
- Special considerations: use with caution in elderly patients, those with respiratory conditions, and when combined with other central nervous system depressants
Administration and Monitoring
- Medical supervision is required during administration due to the risk of respiratory depression
- Resuscitation equipment should be available when used for procedural sedation
- Initial intravenous dose in healthy adults younger than 60 years of age is 1 mg (or no more than .03 mg/kg) injected over 1-2 minutes, as recommended by 1
- Patients older than 60 and those with ASA physical status III or greater require a dose reduction of 20% or more, as noted in 1
Comparison with Other Benzodiazepines
- Midazolam is more potent and faster acting than diazepam, with fewer adverse events, including respiratory depression, as shown in studies by Cole et al and Lee et al, cited in 1 and 1
- Midazolam has superior amnestic properties compared to diazepam, as demonstrated in 1 and 1
From the FDA Drug Label
Midazolam is a short-acting benzodiazepine central nervous system (CNS) depressant. Midazolam is a short-acting benzodiazepine that acts as a central nervous system (CNS) depressant 2 3.
- It is used for sedation and anesthesia.
- The effects of midazolam on the CNS are dependent on the dose administered, the route of administration, and the presence or absence of other medications.
From the Research
Definition and Properties of Midazolam
- Midazolam is an imidazole benzodiazepine with depressant effects on the central nervous system (CNS) 4.
- It has a rapid onset of action and few adverse effects, making it suitable for sedation before diagnostic and therapeutic medical procedures 4.
- Midazolam is water-soluble at acidic pH but becomes lipid-soluble at physiological pH, contributing to its rapid onset of action and good local tolerance after parenteral administration 5, 6, 7.
Uses of Midazolam
- Midazolam is used for sedation before procedures such as gastrointestinal endoscopy, bronchoscopy, diagnostic imaging, and minor plastic surgery 4.
- It is also used as a hypnotic-sedative drug with anxiolytic and amnestic properties, particularly in dentistry and endoscopic procedures 6.
- Midazolam can be used as an adjunct to local anesthetic techniques and as an induction agent for anesthesia, especially in poor-risk, elderly, and cardiac patients 6, 7.
Administration and Pharmacokinetics
- Midazolam can be administered by various routes, including oral, intravenous, intranasal, and intramuscular 4, 5, 7.
- It has a fast absorption rate and is rapidly excreted, with a half-life of approximately 2 hours 5.
- Midazolam produces reliable hypnosis, amnesia, and antianxiety effects, making it a useful addition to the benzodiazepine group 7.
Comparison with Other Sedatives
- Midazolam has been compared to other sedatives such as propofol, diazepam, and thiopental in various studies 4, 8.
- Propofol was found to be more effective in achieving patient-ventilator synchrony and had a shorter duration of action compared to midazolam in critically ill patients 8.
- Midazolam has advantages over thiopental, including its amnestic and anxiolytic properties, but it is not as rapid-acting or predictable in hypnotic effect 7.