Local anaesthetic — maximum safe doses

Maximum safe single dose by agent, with a weight calculator (mg → mL → cartridges). Australian figures lead.

VerifiedTriangulated across three sources: the mg/kg figure is from TG O&D Table 13.9 AND confirmed against the current Australian Product Information (TGA eBS) for every agent — they agree. The calculator uses that AU mg/kg with NO flat cap (the AU position: a guide, not a hard ceiling). A more conservative US ceiling (Malamed) is shown under each amide for reference and is clearly labelled US. Mepivacaine and bupivacaine instead use the cap their AU PI actually sets.

Toxicity comes from the plasma concentration, not the syringe — and the single biggest controllable factor is the rate of injection. No agent is “safer” intravascularly: safety is aspirate + inject slowly + lowest effective dose. Calculate the maximum by weight every time, especially in children, where two cartridges can exceed the limit. The mg/kg maxima are a guide — the usual dental dose is 1–2 cartridges, far below them.TG O&D 2025 — Local anaesthetics in dentistry; Australian Product Information (TGA eBS); Malamed Handbook of LA (Ch.18, p.275–279).

Calculate for this patient

Enter a weight to get the maximum safe single dose for each agent — in milligrams, millilitres of that concentration, and approximate dental cartridges.

Patient weight

Cartridge

Intermediate-actingroutine cartridge agents

Lignocaine (lidocaine)2% with adrenaline 1:80,000Xylocaine Dental · Lignospan Special

7 mg/kg

490mg max

24.5mL of 2%

≈

11cartridges

US ceiling (Malamed): 500 mg ≈ 11 cartridges. TG and the AU PI (Xylocaine Dental, v5.0) give 7 mg/kg as a guide only — no flat mg cap in the AU PI.

The routine workhorse. 2% plain also available; 1:50,000 adrenaline only adds haemostasis, not anaesthesia.

TG O&D 2025 Table 13.9 — 7 mg/kg (~24.5 mL / 70 kg adult; ~7 mL / 20 kg child). · AU PI (Xylocaine Dental v5.0): 7 mg/kg, guide only, no flat cap. Malamed (US): 7 mg/kg with adrenaline, ceiling 500 mg (plain 4.4 mg/kg / 300 mg).

Articaine4% with adrenaline 1:100,000 or 1:200,000Septanest · Ubistesin / Ubistesin Forte · Articadent

7 mg/kg

490mg max

12.3mL of 4%

≈

5cartridges

US ceiling (Malamed): 500 mg ≈ 5 cartridges. The AU PIs (Articadent, Septanest, Ubistesin) give 7 mg/kg for adults AND children, with no flat cap (60 kg worked example ≈ 5 cartridges of 2.2 mL).

Not < 4 yearsMethaemoglobinaemia caution (rare). Contains a sulfur/thiophene moiety.

Commonly used. Older reports of increased paraesthesia not supported by recent prospective data (TG).

TG O&D 2025 Table 13.9 — 7 mg/kg (~12.25 mL adult; ~3.5 mL child). · AU PIs (Articadent/Septanest/Ubistesin): 7 mg/kg adult & child, no flat cap. Malamed (US): 7 mg/kg adult / 5 mg/kg child, ceiling 500 mg.

Prilocaine + felypressin3% with felypressin (or 3% with adrenaline 1:300,000)Citanest Dental with Octapressin

9 mg/kg

630mg max

21.0mL of 3%

≈

9cartridges

US ceiling (Malamed): 600 mg ≈ 9 cartridges. The AU mg/kg figure above (630 mg) passes this more-conservative US limit. The AU PI (Citanest with Octapressin, v5.0) gives 9 mg/kg, no flat cap; it notes methaemoglobinaemia risk rises between 400–600 mg. Felypressin is safe in pregnancy.

Methaemoglobinaemia risk rises 400–600 mg (AU PI). Felypressin is safe in pregnancy.

First-line when adrenaline is contraindicated — felypressin has minimal myocardial effect at 0.03 IU/mL.

TG O&D 2025 Table 13.9 — 9 mg/kg (~21 mL adult; ~6 mL child). · AU PI (Citanest+Octapressin v5.0): 9 mg/kg, no flat cap; methaem 400–600 mg. Malamed (US): 8 mg/kg, ceiling 600 mg.

Short-actingshorter procedures / vasoconstrictor-avoid

Mepivacaine3% plain, or 2% with adrenaline 1:100,000Scandonest (3% Plain · 2% Special)

no mg/kg

AU PI (Scandonest) gives no mg/kg — dosed by age (3% solution): adult ≤ 3 cartridges (6.6 mL ≈ 198 mg); 14–17 y ≤ 4.4 mL; 6–14 y ≤ 2.7 mL (usual 1.35 mL); 3–6 y ≤ 1.8 mL; not < 3 y.

Not < 3 years

Least vasodilating amide — the best plain agent for short procedures or when a vasoconstrictor is to be avoided.

TG O&D 2025 Table 13.9 — no mg/kg in the AU PI; age-banded volumes. · AU PI (Scandonest 3%/2%): adult max 3 cartridges = 6.6 mL (≈198 mg of 3%), by age band, no mg/kg. Malamed (US): 4.4–6.6 mg/kg, ceiling 400 mg.

Prilocaine (plain)4% plainCitanest Dental 4% Plain

6 mg/kg

420mg max

10.5mL of 4%

≈

4cartridges

US ceiling (Malamed): 400 mg ≈ 4 cartridges. The AU mg/kg figure above (420 mg) passes this more-conservative US limit. The AU PI (Citanest 4%) gives 6 mg/kg, no flat cap; the US FDA label is more permissive (8 mg/kg / 600 mg). Methaemoglobinaemia risk rises 400–600 mg; higher in G6PD deficiency.

Methaemoglobinaemia risk rises 400–600 mg; higher in G6PD deficiency. Reverse with methylene blue 1–2 mg/kg IV.

Dental use may be limited. The o-toluidine metabolite is the source of the methaemoglobinaemia risk.

TG O&D 2025 Table 13.9 — 6 mg/kg (~10.5 mL adult; ~3 mL child). · AU PI (Citanest 4% plain): 6 mg/kg, no flat cap. Malamed (US): plain 6 mg/kg, ceiling 400 mg (US FDA label 8 mg/kg / 600 mg).

Long-actingprolonged post-surgical analgesia

Bupivacaine0.5% (± adrenaline 1:200,000)Marcain

no mg/kg

AU Marcain Dental PI (0.5% with adrenaline 1:200,000): ≤ 90 mg per dental sitting = 8 × 2.2 mL cartridges; not < 12 y. General/surgical AU PI: 2 mg/kg, ≤ 150 mg per block, ≤ 400 mg / 24 h.

Not < 12 yearsMost cardiotoxic agent — cardiovascular toxicity may PRECEDE CNS signs. Reserve for long post-surgical analgesia.

Long-acting (soft-tissue analgesia ~4–12 h) for oral surgery. A bupivacaine dental cartridge IS marketed in AU (Marcain Dental, with adrenaline).

TG O&D 2025 Table 13.8 — long-acting; no maximum in Table 13.9. · AU PI: dental 90 mg (8 cartridges) / general 2 mg/kg, 400 mg per 24 h. Malamed (US): 1.3 mg/kg / 90 mg — agrees with the AU dental cap.

Ropivacaineas per product informationNaropin

no mg/kg

No single dental maximum in TG O&D. AU PI (Naropin; ampoules, not cartridges): field block / infiltration ≤ 200 mg, major nerve block ≤ 300 mg single dose, ≤ 800 mg / 24 h. Specialist / hospital use — refer to the PI.

Less cardiotoxic than bupivacaine. Specialist / hospital long-acting agent.

Prolonged analgesia (12–18 h) for postoperative or refractory acute dental pain; less cardiotoxic than bupivacaine.

TG O&D 2025 Table 13.8 — long-acting; no maximum dose stated. · AU PI (Naropin, rev. Feb 2024): indication-specific (≤300 mg single, ≤800 mg/24 h). Not covered by Malamed (US 4th ed).

The figures are the AU position: mg/kg from TG O&D and the Australian PI, with NO flat ceiling applied (both state mg/kg as a guide only). A more conservative US ceiling (Malamed) is shown under each amide for reference. Cartridge count assumes a 2.2 mL AU cartridge; US texts (Malamed) use 1.8 mL — toggle below. The maximum is a ceiling, not a target — usual use is 1–2 cartridges.

TG O&D 2025 Table 13.9 worked example: 70 kg × lignocaine 2% w/ adrenaline → 7 mg/kg × 70 = 490 mg ÷ 20 mg/mL = 24.5 mL ÷ 2.2 mL = ~11 cartridges.

When adrenaline is contraindicated

Avoid adrenaline-containing solutions in:

Known sulfite sensitivity (solutions contain a metabisulfite preservative)
Myocardial infarction in the previous 6 months
Unstable angina
Uncontrolled hypertension
Uncontrolled arrhythmias
Uncontrolled hyperthyroidism

Then: Use prilocaine 3% with felypressin (first-line) or a plain LA with no vasoconstrictor.

Pregnancy: Felypressin is safe in pregnancy.

Cardiac-risk patient who CAN have adrenaline: limit to ~0.04 mg adrenaline = 2 cartridges of 1:100,000 (Malamed, p.319). Never use 1:50,000 or adrenaline retraction cord in cardiovascular disease.

TG O&D 2025 — Adding vasoconstrictors; Malamed Ch.20 (p.318–319).

Systemic toxicity & methaemoglobinaemia

Recognise overdose early — the rate of injection is the single biggest factor.

Early CNS: restlessness, anxiety, tinnitus, dizziness, blurred vision, tremor, drowsiness — then seizures, then cardiovascular toxicity as the level climbs.
Bupivacaine is the exception: cardiovascular toxicity may precede CNS signs.
Seizure management: oxygen, monitor, basic life support; diazepam ~5 mg/min IV (or midazolam 1 mg/min).
Methaemoglobinaemia (slate-grey/blue skin, lips, nails): especially prilocaine > 600 mg, also benzocaine/lidocaine/articaine/tetracaine; higher risk in G6PD deficiency. Reverse with methylene blue 1–2 mg/kg IV; emergency hospital referral.
True allergy to the amide itself is extremely rare — it is usually the metabisulfite preservative. For metabisulfite allergy use felypressin or no vasoconstrictor.

TG O&D 2025 — Adverse effects; Malamed Ch.17–18 (p.275–289), methaemoglobinaemia p.142.

Children — calculate every timeThe maximum is weight-based and easily exceeded: two cartridges of 2% mepivacaine (108 mg) exceed the limit for a 15 kg child (fatalities have resulted). Use a short needle, prefer infiltration to block, and a vasoconstrictor is often unnecessary for short appointments.

% to mg/mLMultiply the percentage by 10. So 2% = 20 mg/mL, 3% = 30 mg/mL, 4% = 40 mg/mL, 0.5% = 5 mg/mL.

AU mg/kg vs US ceilingTG O&D and the Australian PI give the maximum as mg/kg — a guide, with no flat milligram cap. Malamed (US) adds a conservative absolute ceiling (e.g. lignocaine 500 mg); it is shown under each amide for reference and is lower than the weight-based figure in heavier adults. Both agree the usual dose is a fraction of either.

Drugs that raise the LA blood levelCimetidine, quinidine, digitalis (digoxin), desipramine; plus liver and renal disease. Pregnancy lowers the seizure threshold. Reduce the dose accordingly.

The usual dose is far below the maxThese maxima exist to prevent overdose, not to be approached. Most single-quadrant dentistry uses 1–2 cartridges. Aspirate in two planes and inject a 2.2 mL cartridge over ≥ 60 seconds.

Lidocaine (lignocaine) recordArticaine recordMedical emergency in the chairPrescribe by condition

Quick reference for Australian dental practice — not a substitute for the product information or individual clinical judgement. The usual dental dose is far below these maxima: use the lowest effective dose, aspirate, and inject slowly. You confirm the patient's weight, the agent, the concentration and the dose before injecting.

mg/kg from Therapeutic Guidelines: Oral & Dental — Local anaesthetics in dentistry (Tables 13.8–13.9, Sept 2025), confirmed against the current Australian Product Information (TGA eBS) for each agent. TG and the AU PIs express the maximum as mg/kg only, as a guide, with NO flat ceiling — except mepivacaine and bupivacaine, where the AU PI sets a cap. The conservative absolute-mg ceilings shown under the amide agents are US figures from Malamed (Handbook of Local Anesthesia), shown for reference only. Cartridge = 2.2 mL AU cartridge (TG worked example). Brand names verified against the TGA ARTG.

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