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Ultra-Short Acting Benzodiazepine (Procedural Sedation) Pregnancy: There are no or limited data (fewer than 300 pregnancy outcomes) from use in pregnant women; animal studies do not indicate direct or indirect harmful effects with respect to reproductive toxicity. As a precautionary measure it is preferable to avoid the use of Byfavo during pregnancy. Breastfeeding: it is unknown whether remimazolam and its main metabolite (CNS7054) are excreted in human breast milk, but animal data show excretion in milk and a risk to newborns/infants cannot be excluded, so administration to breastfeeding mothers should be avoided; if there is a need to administer it, discontinuation of breastfeeding for 24 hours after administration is advised. Fertility: no human data; no effect on mating or fertility in animal studies.

Remimazolam

Brand names: Byfavo

Remimazolam is an ultra-short-acting benzodiazepine used for procedural sedation and the induction and maintenance of anaesthesia.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: Procedural sedation, adults under 65 years: with an opioid — give the opioid, wait 1 to 2 minutes, then an initial (induction) dose of 5 mg (2 mL) by intravenous injection over 1 minute; wait 2 minutes; then maintenance/titration doses of 2.5 mg (1 mL) over 15 seconds as needed. Without an opioid — induction 7 mg (2.8 mL) over 1 minute, then 2.5 mg (1 mL) over 15 seconds for maintenance/titration
Route: Intravenous injection (reconstitute with sodium chloride 0.9% solution for injection before use)
Frequency: Initial dose then supplemental doses as needed; at least 2 minutes must elapse before any supplemental dose in order to fully assess the sedative effect
Max: Maximal total dose administered in the clinical trials was 33 mg in adults under 65 years, and 17.5 mg in elderly (>= 65 years) and/or ASA-PS III-IV and/or body weight < 50 kg patients. If 5 doses within 15 minutes do not result in the desired level of sedation, an additional or another sedative should be considered.
Source: UK SPC (eMC) for Byfavo 20 mg powder for solution for injection, §4.2 (https://www.medicines.org.uk/emc/product/12746/smpc). ELDERLY >= 65 years and/or ASA-PS III-IV and/or body weight < 50 kg: with an opioid — initial dose 2.5 to 5 mg (1 to 2 mL) over 1 minute after the opioid (waiting 1 to 2 minutes), then maintenance/titration 1.25 to 2.5 mg (0.5 to 1 mL) over 15 seconds; without an opioid — induction 2.5 to 5 mg (1 to 2 mL) over 1 minute, then 1.25 to 2.5 mg (0.5 to 1 mL) over 15 seconds. The opioid example given is 50 micrograms fentanyl, or a suitably reduced dose for elderly or debilitated patients. Dosing should be individually titrated to an effective dose that provides the desired level of sedation and minimises adverse reactions. Onset and offset are fast: in clinical trials peak sedation occurred 3 to 3.5 minutes after the initial bolus and patients became fully alert 12 to 14 minutes from the last dose. Opioids are known to increase the sedative effect and to depress the ventilatory response to carbon dioxide stimulation. ADMINISTRATION SAFETY REQUIREMENTS (§4.2): remimazolam must only be administered by healthcare professionals experienced in sedation; the patient must be monitored throughout by a separate healthcare professional not involved in the procedure whose sole task is monitoring, trained in detecting and managing airway obstruction, hypoventilation and apnoea including maintaining a patent airway, supportive ventilation and cardiovascular resuscitation; respiratory and cardiac function must be continuously monitored; resuscitative medicinal products and age- and size-appropriate equipment for restoring airway patency and bag/valve/mask ventilation must be immediately available; flumazenil (benzodiazepine reversal) must be immediately available. HEPATIC IMPAIRMENT: no dose adjustment for mild (Child-Pugh 5-6) or moderate (Child-Pugh 7-9); in severe hepatic impairment (Child-Pugh 10-15, data from only 3 subjects) effects may be more pronounced and last longer — no dose adjustment is required but careful attention should be paid to the timing of titration doses and remimazolam should be carefully titrated to effect. PAEDIATRIC (non-numeric, so no structured paedDose): 'The safety and efficacy of remimazolam in children and adolescents aged 0 to <18 years have not yet been established. No data are available.' COVERAGE NOTE for this ICU-specialty page: the fetched SPC covers PROCEDURAL SEDATION only. It contains NO regimen for continuous-infusion sedation of mechanically ventilated ICU patients (no mg/kg/h or micrograms/kg/min rate is stated anywhere in this source), so any ICU continuous-sedation dosing must be sourced separately and must not be inferred from the procedural bolus doses above. The US label in this bundle (BYFAVO) is likewise procedural sedation only, with the same 5 mg induction / 2.5 mg supplemental doses and 2.5 to 5 mg induction / 1.25 to 2.5 mg supplemental doses for ASA III-IV.

Dose adjustments

Renal

No dosage adjustment is required in any grade of renal impairment (including patients with glomerular filtration rate [GFR] < 15 mL/min).

Dose auto-extracted from UK Summary of Product Characteristics (SPC) via the eMC; US FDA prescribing information (openFDA / DailyMed) — cross-check; US labelling may differ from UK — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

  • Hypersensitivity to the active substance, other benzodiazepines or any of the excipients
  • Unstable myasthenia gravis

Side effects

  • Hypotension — very common (37.2%; reported as mild in 30.1%, moderate 1.1%, severe 0.1%; diastolic hypotension 8.7% mild)
  • Respiratory depression — very common (13.1%; includes hypoxia 8.0% mild, 0.9% moderate, 0.3% severe, and decreased respiratory rate 1.5% mild)
  • Bradycardia — common (6.8%; mild 6.0%, moderate 0.1%, severe 0.4%)
  • Headache and dizziness — common; somnolence — uncommon
  • Nausea and vomiting — common; hiccups, chills and feeling cold — uncommon; anaphylactic reaction — frequency not known
  • Patients aged 65 years and over had a higher frequency of hypotension (47.0% vs 33.3%) and respiratory depression (22.8% vs 9.0%)

Interactions

  • eMC §4.5 was NOT retrieved in this bundle — the items below come from §4.2 of the same SPC and from the US label; the full UK §4.5 must be checked
  • Opioids — known to increase the sedative effect of remimazolam and to depress the ventilatory response to carbon dioxide stimulation (§4.2, §4.4)
  • Other CNS depressants, including other benzodiazepines and propofol — the sedative effect of intravenous remimazolam can be accentuated; continuously monitor vital signs during sedation and through recovery and titrate to the desired clinical response (US label)
  • Alcohol and benzodiazepines taken concomitantly by the patient — see §4.4 before administration (§4.2 footnote)

Clinical monograph

How it works

It is a positive allosteric modulator at GABA-A receptors producing sedation and hypnosis; its ester linkage is rapidly hydrolysed by tissue esterases to an inactive metabolite, giving a short, predictable recovery.

Prescribing in practice

  • It causes dose-dependent respiratory and cardiovascular depression, so it should be used only with continuous monitoring and immediate access to airway and resuscitation support.
  • Its sedative effect can be reversed with flumazenil, though the offset of remimazolam itself is rapid because of esterase metabolism.
  • Effects are potentiated by concurrent opioids and other central nervous system depressants, requiring careful titration.

Monitoring

Monitor level of consciousness, respiration, oxygen saturation and haemodynamics continuously during and after administration.

Counselling the patient

  • This sedative is given by trained staff with full monitoring in place.
  • You may feel drowsy afterwards; do not drive or make important decisions until fully recovered and advised it is safe.

Evidence & guidelines

Its use for procedural sedation and general anaesthesia is supported by clinical trials and described in the SPC.

Reference: MHRA SPC Byfavo 2021; COSMO study (Pastis et al. Chest 2019); Rex et al. NEJM 2020 (remimazolam for colonoscopy); ESGE/ESGENA Sedation Guidelines 2023; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Related

Curated clinical cross-links plus same-class fallbacks.