Ultra-Short Acting Benzodiazepine (Procedural Sedation) Pregnancy: Avoid — benzodiazepines cross placenta; neonatal sedation; limit to essential procedural indications only during pregnancy

Remimazolam

Brand names: Byfavo

Adult dose

Dose: Induction: 5 mg IV over 1 minute; titrate with supplemental 2.5 mg doses every 2 minutes to desired sedation level; ASA III-IV or ≥65 years: 2.5 mg induction

Route: Intravenous

Frequency: Bolus then supplemental doses every 2 minutes as needed

Max: 35 mg total per procedure

Procedural sedation for diagnostic or minor surgical procedures; fully reversible with flumazenil; MHRA licensed 2021; continuous vital sign monitoring required throughout

Paediatric dose

Dose: Not established N/A/kg

Route: N/A

Frequency: N/A

Max: N/A

Not licensed in paediatrics

Dose adjustments

Renal

No dose adjustment required — remimazolam undergoes organ-independent hydrolysis

Hepatic

No dose adjustment for mild-moderate impairment; use with caution in severe hepatic impairment

Paediatric weight-based calculator

Patient weight (kg)

Not licensed in paediatrics

Clinical pearls

MHRA 2021 approved as first novel benzodiazepine in decades — key advantage: undergoes non-organ-dependent hydrolysis by tissue esterases (similar to remifentanil for opioids) → predictable ultra-short duration (6-12 min after last dose) regardless of organ function
Fully reversible: unlike propofol (which has no reversal agent), remimazolam sedation can be reversed with flumazenil — provides additional safety margin for over-sedation; important in high-risk patients (ASA III-IV, elderly, respiratory compromise)
Cardiovascular stability: superior to propofol in haemodynamic stability — less hypotension in RCTs; particularly advantageous for procedural sedation in elderly, cardiac patients, or haemodynamically compromised patients
Dextran excipient: remimazolam contains dextran 40 — allergy risk in dextran-sensitive patients (rare); skin test recommended in patients with known dextran allergy; different from propofol's lecithin allergy risk
PAION/Cosmo approval: EU licensed by European Commission 2021; positioned between midazolam (long-acting, not titratable) and propofol (no reversal agent) for moderate-to-deep procedural sedation; ideal for endoscopy, short procedures, bronchoscopy

Contraindications

Known hypersensitivity to benzodiazepines or dextran (excipient)
Absence of resuscitation facilities
Benzyl alcohol hypersensitivity (excipient)

Side effects

Hypotension
Bradycardia
Respiratory depression (less than propofol at equipotent doses)
Dizziness
Hiccups
Nausea
Pain at injection site

Interactions

Opioids — additive sedation and respiratory depression; reduce remimazolam dose by 25% when co-administered
CYP3A4 inhibitors — minimal effect (remimazolam primarily metabolised by esterases, not CYP)
Flumazenil — full reversal agent for remimazolam

Monitoring

Continuous SpO2, ECG, ETCO2 (capnography) during procedure
Blood pressure every 3-5 minutes
Level of sedation (MOAA/S scale)
Respiratory rate
Recovery — observe minimum 15 minutes after last dose

Reference: BNFc; BNF 90; MHRA SPC Byfavo 2021; COSMO study (Pastis et al. Chest 2019); Rex et al. NEJM 2020 (remimazolam for colonoscopy); ESGE/ESGENA Sedation Guidelines 2023. Verify against your local formulary and the latest BNF before prescribing.

Curated clinical cross-links plus same-class fallbacks.

Calculators