Local Anaesthetic Maximum Dose Calculator
The calculation every dental student is examined on, and the one most often got wrong — usually by forgetting that a 4% articaine cartridge carries twice the milligrams of a 2% lidocaine cartridge of identical volume.
Educational tool — not for clinical use
These are the conventional teaching maxima. They differ between national formularies and between manufacturers, and the binding constraint in a real patient is often not body weight at all. Always check the manufacturer’s summary of product characteristics and your local guidelines, and never treat this page as authority for a dose.
The UK dental workhorse. The adrenaline is what permits the higher weight-based maximum, by slowing systemic absorption.
Maximum for a 70 kg patient
11cartridges
490 mg maximum, at 44.0 mg per 2.2 mL cartridge.
- Weight-based maximum
- 7 mg/kg
- Absolute maximum
- 500 mg
- Concentration
- 2% (20 mg/mL)
Vasoconstrictor load
Adrenaline 1:80,000. At 11 cartridges that is 303 µg of adrenaline.
- ⚠ Exceeds the conventional 200 µg ceiling for a healthy adult.
- ⚠ Exceeds the conservative 40 µg ceiling used in significant cardiac disease.
This is the point worth internalising: in a cardiac patient the adrenaline load usually becomes the limiting factor long before the anaesthetic maximum does. Endogenous catecholamine release from inadequate analgesia exceeds either figure — see cardiac risk in the dental chair.
How the arithmetic works
A percentage concentration is grams per 100 mL, which means each percent is 10 mg per mL. A 2% solution is therefore 20 mg/mL, and a 2.2 mL cartridge of it holds 44 mg. Multiply the weight-based maximum in mg/kg by the patient’s weight, compare that against the absolute ceiling for the agent, and take whichever is lower. Divide by the milligrams per cartridge, and floor the result.
Two things routinely catch people out. The first is concentration: articaine at 4% and prilocaine at 3% do not behave like lidocaine at 2%, even at the same volume. The second is that the anaesthetic maximum is frequently not the binding constraint — in a patient with significant ischaemic heart disease, the conservative 40 µg adrenaline ceiling is reached at well under two cartridges of 1:80,000, long before any lidocaine limit.
And the point most worth remembering: inadequate anaesthesia releases far more endogenous catecholamine than any cartridge contains. Adequate analgesia is cardioprotective, not a cardiac risk.
Revise the underlying anatomy
Why an inflamed tooth resists a block, why the mandibular foramen is where it is, and what the needle passes through on the way — the cranial nerves module and the oral cavity module cover both.
Medical disclaimer
This page is for general education and does not replace personalised medical advice. If you have concerning symptoms, or before starting a new supplement, medication or exercise programme, speak with a qualified healthcare professional.