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# Midazolam

A short-acting benzodiazepine for sedation in procedures and intensive care. Given IV it can stop breathing, so it needs continuous monitoring.

Updated 2026-11-01

- Class: [Benzodiazepines](https://durgical.com/en/pharmacology/classes/benzodiazepines/)
- Receptor: GABA-A receptor, benzodiazepine site
- ATC code: N05CD08
- WHO Model List of Essential Medicines

## ⚠ High-alert medication

An error with this medicine can cause serious harm: double checks and protocols are used.

◎**GABA-A receptor, benzodiazepine site**Midazolam

ⓘ The figure shows diazepam, a benzodiazepine that occupies the same site, bound to the human GABA-A receptor (α1β2γ2) with GABA; no structure with midazolam is available.

**Target in 3D:** GABA-A receptor, benzodiazepine site. PDB structure 6X3X (RCSB PDB, public domain). [View the structure at RCSB PDB](https://www.rcsb.org/structure/6X3X) · Drag to rotate · pinch to zoom

## Mechanism of action

Midazolam binds the benzodiazepine site of the GABA-A receptor and makes GABA open the chloride channel more often. It acts quickly, giving sedation, anxiety relief and amnesia for the procedure. CYP3A4 breaks it down to alpha-hydroxymidazolam, which may add to its effect.

- Binds the benzodiazepine site of the GABA-A receptor
- GABA opens the chloride channel more often
- Rapid sedation, anxiety relief and amnesia
- CYP3A4 breaks it down; the effect wears off in hours

## Pharmacokinetics

**Metabolism**
In the liver by CYP3A4 to alpha-hydroxymidazolam

**Half-life**
About 3 hours on average in healthy adults (range about 1.8 to 6.4); much longer in seriously ill newborns

**Onset and duration**
Sedation within about 3 to 5 minutes after IV injection

## Indications

- Sedation, anxiety relief and amnesia before surgery
- Sedation for diagnostic, therapeutic and endoscopic procedures
- Induction of general anaesthesia
- Continuous sedation of intubated, ventilated patients in intensive care

## Adverse effects

### Common

- Drop in breathing rate and depth
- Low blood pressure
- Hiccups, nausea and vomiting
- Pain at the injection site
- Paradoxical agitation

### Serious (rare, important)

- Respiratory depression and respiratory arrest, especially outside critical care settings
- Profound sedation, respiratory depression, coma and death when combined with opioids
- Abuse, misuse and addiction
- Physical dependence; stopping suddenly can cause life-threatening withdrawal, including seizures
- Severe hypotension and seizures after rapid IV injection in newborns, especially with fentanyl

## Contraindications

- Hypersensitivity to midazolam
- Acute narrow-angle glaucoma

## Key interactions

**Opioids**
Profound sedation, respiratory depression, coma and death

**Alcohol and other central nervous system depressants**
Additive sedation and breathing depression

**CYP3A4 inhibitors (erythromycin, diltiazem, verapamil, ketoconazole, itraconazole, cimetidine)**
Slower clearance and prolonged sedation

## What is monitored

- Continuous pulse oximetry and breathing; capnography where available
- Heart rate and blood pressure
- Sedation level with a sedation scale
- Recovery before discharge after a procedure

## Administration and safety

- Used only where breathing and heart function can be watched continuously, with resuscitation equipment and trained staff
- IV doses are individualised and titrated slowly; never a rapid push in newborns
- Several strengths exist: concentration is double-checked before drawing up
- Opioid doses are reduced when given together

## Nursing care

- Baseline vital signs, oxygen saturation and airway assessment before sedation
- Watch breathing continuously during and after the dose
- Have flumazenil, oxygen and a bag-valve mask at the bedside
- Teach that memory of the procedure may be lost and that driving is avoided afterwards

## Pregnancy and breastfeeding

Use late in pregnancy can cause sedation and withdrawal symptoms in the newborn, who is watched after birth.

## Memory aid

Midazolam: «MIDway to sleep, fast in, fast out» – minutes to act, hours to wear off; always with a monitor.

## Test yourself

Think of the answer, then tap the question to see it.

## Why is IV midazolam a high-alert medicine?

It can cause respiratory depression and arrest; it needs continuous monitoring and rescue equipment.

## Which enzyme breaks down midazolam, and what happens with erythromycin?

CYP3A4; erythromycin slows its clearance and prolongs sedation.

## What can rapid IV midazolam cause in newborns?

Severe hypotension and seizures, especially with fentanyl.

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## Related drugs

- [Diazepam](https://durgical.com/en/pharmacology/diazepam/)
- [Lorazepam](https://durgical.com/en/pharmacology/lorazepam/)
- [Fentanyl](https://durgical.com/en/pharmacology/fentanyl/)
- [Flumazenil](https://durgical.com/en/pharmacology/flumazenil/)

[← Back to the class: Benzodiazepines](https://durgical.com/en/pharmacology/classes/benzodiazepines/)

Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.

Sources: [DailyMed - MIDAZOLAM- midazolam hydrochloride injection, solution](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=1abda8b8-48a8-4995-af86-39220d1aa240) (DailyMed (U.S. National Library of Medicine), 2026); [ATCDDD - ATC/DDD Index](https://atcddd.fhi.no/atc_ddd_index/?code=N05CD08) (WHO Collaborating Centre for Drug Statistics Methodology, 2026); Goodman & Gilman's The Pharmacological Basis of Therapeutics, 14th ed., ch. 22 (McGraw Hill, 2023).

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Representative model, for educational purposes only.

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