UKMedCalc

For healthcare professionals. Educational tool only — not a medical device. Verify all results against the current BNF, NICE guidance and local policy, and apply clinical judgement.

Anaesthesia

Local Anaesthetic Maximum Dose

Calculates the weight-based maximum dose of common local anaesthetics, applying the lower of the weight-based limit and the absolute cap.

kg
Enter the required values to see the result.

Formula

Max dose=min⁡(weight×mg/kg limit,  absolute cap)\text{Max dose} = \min(\text{weight} \times \text{mg/kg limit}, \; \text{absolute cap})

Values assume a healthy adult and infiltration/peripheral administration. Sources (BNF, SmPCs, textbooks) differ slightly for some agents — verify against the product literature.

Caveats & limitations

  • Maxima are not targets — use the lowest effective dose, aspirate before injecting, and inject incrementally.
  • Highly vascular sites (e.g. intercostal, epidural, paracervical) absorb faster and carry higher toxicity risk.
  • Dental cartridge dosing (mg per cartridge) differs — do not use this tool for dental blocks.
  • Prilocaine above ~600 mg risks methaemoglobinaemia; bupivacaine cardiotoxicity can precede CNS signs.

Evidence & UK guidance

Primary evidence

  • Tucker GT, Mather LE. Clinical pharmacokinetics of local anaesthetics. Clin Pharmacokinet. 1979;4(4):241–278. (Maxima in current practice are taken from the BNF and product SmPCs.)

UK practice

The BNF and individual SmPCs list maximum doses, which differ slightly between sources and between preparations. Reduce maxima in the elderly, pregnancy, hepatic or cardiac disease, and low plasma proteins. Ensure intralipid 20% and a local anaesthetic systemic toxicity (LAST) plan are immediately available for significant blocks (RA-UK/AAGBI guidance).

Official resources

Formula and citations last verified: 2026-08-03

Related calculators

IBW / AdjBW

Calculates Devine ideal body weight and, when actual weight is provided, adjusted body weight for dosing in obesity.

BSA

Calculates body surface area using the Mosteller equation (UK standard) with the Du Bois equation for comparison.