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Remimazolam

  • BenzodiazepinesBenzodiazepines
  • High alertAn error with this medicine can cause serious harm: double checks and protocols are used.

An ultra-short-acting intravenous benzodiazepine broken down by tissue esterases. Used for procedural sedation and, in some countries, anaesthesia.

Updated

Quick facts

Group
Benzodiazepines
Target
GABA-A receptor, benzodiazepine site
Used for
Sedation for short procedures in adults
Key effects
Low blood pressure · Low oxygen saturation · Nausea
Monitor
Continuous oxygen saturation · Depth of sedation
ATC
N05CD14

No doses: the clinician sets them by the current guideline.

Mechanism of action

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

Target in 3D: GABA-A receptor, benzodiazepine site. PDB structure 6X3X (RCSB PDB, public domain). View the structure at RCSB PDB

Remimazolam binds the benzodiazepine site of the GABA-A receptor, like midazolam, and increases the chloride current that GABA opens, so neurons are hyperpolarised and the patient is sedated. It was designed as a 'soft drug': an ester group lets tissue esterases (mainly liver carboxylesterase) split it quickly into an inactive metabolite, an idea also used for remifentanil. So it wears off fast, even after long infusions, and flumazenil can reverse it.

  1. Binds the benzodiazepine site of GABA-A
  2. More chloride enters: neurons hyperpolarise
  3. Sedation and amnesia within moments
  4. Esterases split it to an inactive acid: fast offset

Indications

  • Sedation for short procedures in adults (for example endoscopy, bronchoscopy)
  • Induction and maintenance of general anaesthesia (approved in some countries)

Adverse effects

Common

  • Low blood pressure (less than with propofol)
  • Low oxygen saturation and slowed breathing
  • Changes in heart rate
  • Nausea, vomiting, headache, drowsiness

Contraindications

  • Hypersensitivity to remimazolam or other benzodiazepines
  • Use without staff and equipment for airway management and monitoring

Key interactions

Opioids
Usually given together; deeper sedation and respiratory depression.
Alcohol and other CNS depressants
Additive sedation.
Flumazenil
Reverses the sedation; re-sedation is possible, so it is not used routinely.

What is monitored

  • Continuous oxygen saturation, breathing and capnography where available
  • Blood pressure and heart rate
  • Depth of sedation and recovery before discharge

Administration and safety

  • Intravenous only, by staff trained in sedation, with oxygen, airway equipment and flumazenil available.
  • Usually given with an opioid; each dose is titrated to effect.
  • No pain on injection, unlike propofol.

Pregnancy and breastfeeding

Information on use in pregnancy is limited.

Nursing care

  • Before: confirm fasting, airway assessment and baseline vital signs.
  • During: watch breathing, oxygen saturation and blood pressure continuously.
  • After: monitor until awake and stable; no driving the same day.
  • Report delayed waking, especially in liver disease.

Pharmacokinetics

Absorption
Intravenous only.
Metabolism
Hydrolysed by tissue esterases (liver carboxylesterase) to an inactive metabolite, not by CYP enzymes.
Elimination
Metabolites are excreted in the urine.
Onset and duration
Rapid onset and recovery; offset is faster than midazolam, close to propofol.

Test yourself

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

Why does remimazolam wear off faster than midazolam?

Tissue esterases rapidly split its ester to an inactive metabolite.

Which antidote reverses remimazolam?

Flumazenil, the benzodiazepine-site antagonist.

Which other anaesthetic drug uses the same 'ester soft drug' design?

Remifentanil.

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More Pharmacology questions →

Connections

← Back to the class: 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: Remimazolam: pharmacological characteristics and clinical applications in anesthesiology (Anesthesia and Pain Medicine, via PubMed Central, 2022); Human GABAA receptor alpha1-beta2-gamma2 subtype in complex with GABA plus diazepam (RCSB Protein Data Bank, 2020); ATCDDD - ATC/DDD Index (WHO Collaborating Centre for Drug Statistics Methodology, 2026).

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Representative model, for educational purposes only.