The maximum dose of Lidocaine (without adrenaline) for local anaesthesia is
3 mg/kg
The correct answer is 3 mg/kg. Lidocaine blocks voltage-gated sodium channels. Injected plain, its own vasodilator effect speeds systemic absorption, so the maximum safe dose is 3 mg/kg (about 200 mg, or 20 mL of 1% solution, in a 70 kg adult). Adrenaline 1:200,000 causes vasoconstriction, slows absorption and raises the ceiling to about 7 mg/kg (500 mg).
2 mg/kg is the safe limit of plain bupivacaine, not lidocaine. 4 mg/kg is quoted for plain prilocaine but is not the accepted lidocaine figure. 6 mg/kg approaches the adrenaline-containing dose and, given plain, risks systemic toxicity: perioral tingling, tinnitus, metallic taste, drowsiness, then seizures and cardiovascular collapse.
Key point: Remember 3 and 7 for lidocaine (plain versus with adrenaline), and 2 and 3 for bupivacaine. Toxicity is treated with airway support, benzodiazepines and 20% Intralipid emulsion.
Similar Questions
Which of the following parameters are assessed during preoperative airway assessment for a surgical patient?
1. Mouth opening
2. Ability to protrude the jaw
3. Thyromental distance
4. Cervicomental distance
Select the correct answer using the code given below.
Important Questions from Anaesthesia & Pain Management
- Rapid Sequence Induction is indicated in:
- Preoperative Samsoon and Young modified, Mallampati test is used for assessing:
- Which one of the following is a Nephrotoxic anaesthetic agent?
- A 56-year-old female has been diagnosed with gallstones and is undergoing a preanaesthesia checkup. She has been a diabetic since last 15 years, but sugar levels are within the limits. Which category of physical status does she fit into?
- Which one of the following is a Nephrotoxic anaesthetic agent?
