Drug Dose Calculator

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Propofol 10 mg/ml (1%) SmPC, emc 5492, §4.2 — adults <55 yr 1.5–2.5 mg/kg; child >8 yr ≈2.5 mg/kg; 1 month–8 yr 2.5–4 mg/kg; not recommended below 1 month. Over 55 yr and ASA 3–4: the SmPC says reduce and titrate; 1.0–1.5 mg/kg is the figure in the Diprivan US prescribing information (AstraZeneca/Fresenius Kabi, 2017). Scalar: lean body weight — Nightingale et al, Anaesthesia 2015;70:859, Table 3; Ingrande, Brodsky & Lemmens, Anesth Analg 2011;113:57.

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Propofol 10 mg/ml (1%) SmPC, emc 5492, §4.2 — adults 4–12 mg/kg/h; child over 1 month 9–15 mg/kg/h. Scalar for the infusion is adjusted body weight, not lean — Nightingale et al, Anaesthesia 2015;70:859, Table 3. Marsh and Schnider TCI models are unreliable above 140–150 kg (same guideline).

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Sources disagree and the range spans both: Thiopental 500 mg SmPC, emc 9376, §4.2 — 4–6 mg/kg for a normal adult; Pentothal US prescribing information — 3–4 mg/kg for rapid induction in an average 70 kg adult. Paediatric figures from the same SmPC: newborn 3–4, infant 5–8, child 5–6 mg/kg. Reconstituted at 2.5% = 25 mg/ml. Scalar: lean body weight — Nightingale et al, Anaesthesia 2015;70:859, Table 3, which also warns that awareness risk is higher with thiopental if maintenance is delayed.

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Ketalar 10 mg/ml SmPC, emc 2231, §4.2 — IV induction 1–4.5 mg/kg, average 2.0 mg/kg giving 5–10 min of surgical anaesthesia, injected over 60 s; IM 6.5–13 mg/kg. The 1–2 mg/kg shown is the usual induction band inside that label range. No separate paediatric dose is given. Scalar: Nightingale et al, Anaesthesia 2015;70:859 does not list ketamine — recommendation 11 of that guideline (dose on lean body weight and titrate to effect) is applied.

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Etomidate 2 mg/ml SmPC, emc 15214, §4.2 — hypnotic dose 0.3 mg/kg (0.15 ml/kg), sleep 4–5 min; Hypnomidate SmPC, emc 9777. US label range 0.2–0.6 mg/kg, usual 0.3, over 30–60 s. The SmPC gives no separate paediatric dose — use a paediatric reference in a child. Scalar: lean body weight by recommendation 11 of Nightingale et al, Anaesthesia 2015;70:859 (etomidate is not in Table 3).

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Midazolam 1 mg/ml SmPC, emc 13192, §4.2 — premedication, adult under 60/ASA I–II: 1–2 mg IV repeated, or 0.07–0.1 mg/kg IM; 60 yr and over, debilitated or chronically ill: 0.5 mg IV initially, 0.025–0.05 mg/kg IM. Paediatric conscious sedation IV: 6 months–5 yr 0.05–0.1 mg/kg (total not above 6 mg), 6–12 yr 0.025–0.05 mg/kg (total not above 10 mg). Below 6 months IV midazolam is for intensive care with airway control only. Not in the AAGBI obesity table — total body weight shown, titrate.

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Suxamethonium Chloride 50 mg/ml SmPC, emc 3401, §4.2 — adults 1 mg/kg IV for intubation; children 1–12 yr 1–2 mg/kg; infants under 1 yr 2 mg/kg; total dose not to exceed 500 mg. Scalar: total body weight, because plasma cholinesterase activity rises with obesity — Nightingale et al, Anaesthesia 2015;70:859, §Drug dosing; Lemmens & Brodsky, Anesth Analg 2006;102:438.

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Esmeron 10 mg/ml SmPC, emc 1345, §4.2 — 0.6 mg/kg gives intubating conditions within 60 s in nearly all patients. Scalar: lean body weight — Nightingale et al, Anaesthesia 2015;70:859, Table 3 (total body weight does not shorten onset but markedly prolongs the block); Leykin et al, Anesth Analg 2004;99:1086 dosed on ideal body weight.

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Esmeron 10 mg/ml SmPC, emc 1345, §4.2 — 1.0 mg/kg for rapid sequence induction, intubating conditions within 60 s (0.6 mg/kg needs 90 s). The upper 1.2 mg/kg is the dose to which the sugammadex 16 mg/kg immediate-reversal figure is tied — Bridion 100 mg/ml SmPC, emc 6409, §4.2.

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Vecuronium bromide 10 mg SmPC, emc 14772, §4.2 and §6.6 — 80–100 µg/kg IV gives intubating conditions in 90–120 s; maintenance 20–30 µg/kg at 25% twitch recovery; 10 mg vial plus 5 ml water for injections = 2 mg/ml. Scalar: lean body weight — Nightingale et al, Anaesthesia 2015;70:859, Table 3.

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Atracurium Besilate 10 mg/ml SmPC, emc 12628, §4.2 — adult range 0.3–0.6 mg/kg; intubation within 90 s after 0.5–0.6 mg/kg; supplements 0.1–0.2 mg/kg. Scalar: lean body weight — Nightingale et al, Anaesthesia 2015;70:859, Table 3.

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Cisatracurium 2 mg/ml SmPC, emc 2595, §4.2 — 0.15 mg/kg for intubation, good conditions at 120 s after propofol induction; maintenance 0.03 mg/kg (adult) or 0.02 mg/kg (2–12 yr); paediatric intubating dose 0.15 mg/kg given over 5–10 s. Scalar: cisatracurium is not in Table 3 of Nightingale et al, Anaesthesia 2015;70:859 — lean body weight is applied, as for atracurium and vecuronium in that table, and titrated to train-of-four.

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Robinul-Neostigmine (glycopyrronium 0.5 mg + neostigmine metilsulfate 2.5 mg per ml) SmPC, emc 6599, §4.2 — adults, elderly and children 0.02 ml/kg IV over 10–30 s, equal to neostigmine 50 µg/kg with glycopyrronium 10 µg/kg; total doses above 2 ml are not recommended, since that much neostigmine may itself produce depolarising block. Scalar: adjusted body weight, neostigmine maximum 5 mg — Nightingale et al, Anaesthesia 2015;70:859, Table 3. Give only once there is measurable twitch recovery.

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Bridion 100 mg/ml SmPC, emc 6409, §4.2 — 2 mg/kg once spontaneous recovery has reached reappearance of T2; 4 mg/kg at 1–2 post-tetanic counts with no TOF response; 16 mg/kg if reversal is needed about 3 min after a single 1.2 mg/kg dose of rocuronium. Paediatric 2 and 4 mg/kg apply from birth to 17 yr; immediate reversal has not been investigated in children. Weight: the SmPC directs that in morbidly obese patients the dose is based on actual body weight; Nightingale et al, Anaesthesia 2015;70:859, Table 3 instead lists sugammadex under adjusted body weight, referring to the product literature — both figures are shown when they differ.

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Fentanyl 50 µg/ml SmPC, emc 6617, §4.2 — adult initial dose 50–200 µg (about 1–3 µg/kg at 70 kg), supplements 50 µg spontaneously breathing or 100–200 µg ventilated; children 2–11 yr 1–3 µg/kg initially, 1–1.25 µg/kg supplements; 12–17 yr as adults; doses above 200 µg are for anaesthesia only. Scalar: lean body weight — Nightingale et al, Anaesthesia 2015;70:859, Table 3; Shibutani et al, Br J Anaesth 2005;95:377.

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Morphine Sulfate 10 mg/ml SmPC, emc 6426, §4.2 — usual adult IV 2.5–15 mg not more often than 4-hourly, titrated to response, injected slowly over 4–5 min; the weight-based equivalent quoted is 0.1–0.2 mg/kg 4-hourly. Give it in 1–2 mg increments and wait. Paediatric morphine is age-banded and is not in the adult label — use BNF for Children. Scalar: lean body weight — Nightingale et al, Anaesthesia 2015;70:859, Table 3.

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Remifentanil 2 mg SmPC, emc 795, §4.2 — induction bolus 1 µg/kg given over not less than 30 s. Scalar: ideal body weight — the same SmPC directs that in obese patients the dose is reduced and based on ideal rather than actual body weight, since clearance and volume of distribution track ideal body weight; Egan et al, Anesthesiology 1998;89:562.

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Remifentanil 2 mg SmPC, emc 795, §4.2 — induction infusion 0.5–1 µg/kg/min; maintenance with propofol starts at 0.25 µg/kg/min, range 0.05–2 µg/kg/min (with 66% nitrous oxide, start 0.4). Volume shown at 50 µg/ml (2 mg in 40 ml); check your own dilution on the Infusion Rate tool.

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Resuscitation Council UK, Emergency treatment of anaphylaxis, May 2021, §5.1.1 — 1 mg/ml (1:1000) IM in the anterolateral thigh: over 12 yr and adults 500 µg (0.5 ml); 6–12 yr 300 µg; 6 months–6 yr 150 µg; under 6 months 100–150 µg. Give 300 µg to a child who is small or prepubertal. Repeat after 5 min if no improvement; after two doses treat as refractory anaphylaxis. If there is no IV access peri-operatively, 10 µg/kg IM to a maximum of 500 µg — Dodd, Turner, Soar & Savic, Anaesthesia 2024;79:535, Resuscitation Council UK peri-operative anaphylaxis algorithm.

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Dodd, Turner, Soar & Savic, Anaesthesia 2024;79:535 — Resuscitation Council UK peri-operative anaphylaxis algorithm for anaesthetists: initial IV bolus, adult and child over 12 yr 50 µg (0.5 ml of 1 mg/10 ml, 1:10,000); child under 12 yr 1 µg/kg, needing careful dilution and titration. Same algorithm: fluid bolus 500–1000 ml adult, 20 ml/kg child. Resuscitation Council UK 2021 restricts IV adrenaline to practitioners who titrate vasopressors routinely.

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Resuscitation Council UK, Adult advanced life support — 1 mg IV as soon as possible in a non-shockable rhythm, after the third shock in VF/pVT, repeated every 3–5 min. Paediatric: 10 µg/kg IV/IO (0.1 ml/kg of 1:10,000), repeated every 3–5 min — Resuscitation Council UK, Paediatric advanced life support 2021, and the RCUK/Association of Paediatric Anaesthetists paediatric emergency drug chart.

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Resuscitation Council UK, Adult advanced life support — with adverse signs give atropine 500 µg IV, repeat every 3–5 min to a total of 3 mg. Paediatric: 20 µg/kg, maximum 600 µg (Resuscitation Council UK). The 100 µg minimum applied here is AHA 2020 PALS; RCUK and ERC set no minimum — Paediatric advanced life support 2021, and the RCUK/APA paediatric emergency drug chart. Volume shown at 600 µg/ml; a 1 mg in 10 ml prefilled syringe is 100 µg/ml.

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Ephedrine Hydrochloride 30 mg/ml SmPC, emc 9291, §4.2 — hypotension from spinal or epidural anaesthesia: slow IV increments of 3–7.5 mg, up to 30 mg total; the 3 mg/ml prefilled syringe SmPC, emc 5354, gives 3–6 mg (maximum 9 mg) repeated every 3–4 min to the same 30 mg ceiling. Safety and efficacy under 12 yr are not established. Volume shown at 3 mg/ml — the 30 mg/ml ampoule is diluted to 10 ml before use.

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Phenylephrine 100 µg/ml SmPC, emc 12563, §4.2 — hypotension during spinal, epidural or general anaesthesia: IV bolus 50–100 µg repeated to effect, no single bolus above 100 µg; infusion 25–50 µg/min initially, up to 100 µg/min. Safety and efficacy in children have not been established and no data are available.

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Resuscitation Council UK, Adult advanced life support — amiodarone 300 mg IV after three shocks, a further 150 mg after five shocks (lidocaine 100 mg then 50 mg if amiodarone is unavailable). Paediatric: 5 mg/kg after the third and fifth shocks, maximum 300 mg — RCUK/APA paediatric emergency drug chart, 2021. Concentration 150 mg in 3 ml = 50 mg/ml, Amiodarone SmPC, emc 8739.

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Adult acute severe asthma: 1.2–2 g IV over 20 min, single dose, after senior discussion — BTS/SIGN British guideline on the management of asthma, SIGN 158, 2019. Eclampsia: 4–5 g (16–20 mmol Mg²⁺) loading then 1–2 g/h — Magnesium Sulfate 50% w/v SmPC, emc 13170, §4.2. Child, torsade de pointes or documented hypomagnesaemia: 25–50 mg/kg over several minutes, maximum 2 g — Resuscitation Council UK, Paediatric advanced life support 2021. Adult torsade doses differ between guidelines — follow your local protocol. 50% w/v = 500 mg/ml (2 mmol Mg²⁺ per ml).

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No longer routine: Resuscitation Council UK, Emergency treatment of anaphylaxis, May 2021, §5.5 — "The routine use of corticosteroids to treat anaphylaxis is not advised"; consider only after initial resuscitation for refractory reactions or ongoing asthma or shock, and never in preference to adrenaline. Doses retained from Resuscitation Council UK, Emergency treatment of anaphylactic reactions, 2008, Figure 3 (IM or slow IV): adult and child over 12 yr 200 mg; 6–12 yr 100 mg; 6 months–6 yr 50 mg; under 6 months 25 mg. Solu-Cortef 100 mg reconstituted with 2 ml = 50 mg/ml, SmPC emc 1542.

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No longer routine: Resuscitation Council UK, Emergency treatment of anaphylaxis, May 2021, §5.4 — antihistamines are not recommended in the initial emergency treatment and have no role in airway, breathing or circulation problems; non-sedating oral antihistamines are preferred for skin symptoms. Doses retained from Resuscitation Council UK 2008, Figure 3 (IM or slow IV): adult and child over 12 yr 10 mg; 6–12 yr 5 mg; 6 months–6 yr 2.5 mg; under 6 months 250 µg/kg. Concentration 10 mg/ml.