Midazolam
A short-acting benzodiazepine given for procedural sedation, anesthesia, sedation in intensive care and prolonged seizures.
Drug card
- Class
- Benzodiazepine
- How it works
- Boosting GABA at GABA-A receptors, so chloride channels open more often
- Used for
- Sedation and amnesia for procedures
- Premedication and induction of general anesthesia
- Sedation of ventilated patients in intensive care
- Prolonged convulsive seizures
- Known for
- Slowed breathing, apnea and respiratory arrest
- Amnesia for events during and after the procedure
- Its name
- -azepam, -azolam means a benzodiazepine
Study it as a flashcard, and it comes back before you forget it.
Mechanism of action
How does midazolam work?
Midazolam, a benzodiazepine with an imidazole ring, binds the benzodiazepine site of GABA-A receptors and enhances GABA's inhibition, producing sedation, anxiety relief and marked amnesia. CYP3A4 clears it, with an elimination half-life of about 3 hours, so its effects are brief unless CYP3A4 inhibitors slow its clearance.
Like other benzodiazepines: Benzodiazepines bind their own site on the GABA-A receptor, apart from the GABA site, and increase the receptor's affinity for GABA. The chloride channel then opens more often, hyperpolarizing neurons and damping their firing. Depending on the drug and dose, the result is anxiety relief, sedation, muscle relaxation, seizure control and amnesia.
Uses
What is midazolam used for?
- Sedation and amnesia for procedures
- Premedication and induction of general anesthesia
- Sedation of ventilated patients in intensive care
- Prolonged convulsive seizures
Side effects
Side effects of midazolam
- Slowed breathing, apnea and respiratory arrestKnown forSerious
- Amnesia for events during and after the procedureKnown for
- Low blood pressureSerious
- Oversedation and drowsiness
- Paradoxical agitation or involuntary movements
- Nausea and vomiting
- Pain or redness at the injection site
- Dependence after prolonged infusionSerious
- Withdrawal symptoms when a long infusion stopsSerious
Known for marks what an exam expects you to know it for.
Watch for
Cautions and what sets it apart
- Give IV midazolam only where breathing and heart rhythm are monitored, with resuscitation equipment, trained staff and flumazenil at hand.
- Opioids and other sedatives deepen its respiratory depression; titrate slowly and use lower doses in older or frail people.
- CYP3A4 inhibitors such as erythromycin, diltiazem and azole antifungals prolong and deepen its effect.
- Do not give by rapid injection to neonates: severe hypotension and seizures have followed.
Good to know: The shortest-acting benzodiazepine here; besides IV and IM use, an oromucosal (buccal) form is given to children with epilepsy for prolonged seizures.
Remember it
A way to remember it
CALMS
- C
- Convulsions controlled
- A
- Anxiety relief
- L
- Loss of memory for events after a dose (amnesia)
- M
- Muscle relaxation
- S
- Sedation
Written for biofideX
Its name
-azepam, -azolam means benzodiazepine
Diazepam and lorazepam end in -azepam; alprazolam and midazolam, with an added triazole or imidazole ring, end in -azolam. Clobazam and chlordiazepoxide are benzodiazepines too.
- Every drug name stem
Its class
Benzodiazepines
Other benzodiazepines with a card:
Easily mixed up with Z-drugs.
Sources
Checked against
Written for biofideX in plain words, after checking these references:
- Midazolam injection: label (DailyMed)
- Midazolam in sodium chloride injection: label (DailyMed)
- Midazolam 10 mg oromucosal solution: SmPC (emc)
- Midazolam (NCI Thesaurus)
For learning pharmacology, not for treatment decisions: no doses are given, and a prescriber, pharmacist or the product's own label is the word on any one patient. Spotted a mistake? Tell us and we'll correct it.
Depression, anxiety and sleep
Midazolam is one of 15 drugs practiced together here: their classes, how they work, what they treat and what they're known for.
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