Lidocaine Dose Calculator
Calculate the maximum safe subcutaneous lidocaine dose based on patient weight, concentration, and epinephrine use. Free lidocaine dosing calculator for medical professionals with mg/mL results, breakdowns, and safety guidelines.
About This Calculator
The Lidocaine Dose Calculator helps healthcare professionals determine the maximum safe subcutaneous dose of lidocaine based on patient weight, lidocaine concentration, and whether epinephrine is added. Lidocaine is the most commonly used local anesthetic across medical specialties including dentistry, dermatology, emergency medicine, and minor surgical procedures.
Lidocaine works by blocking voltage-gated sodium channels in nerve cell membranes, preventing the conduction of pain signals. While lidocaine has a good safety margin, exceeding the maximum recommended dose can lead to serious complications including CNS toxicity (seizures, respiratory depression) and cardiovascular collapse. The standard maximum doses are 4.5 mg/kg without epinephrine and 7 mg/kg with epinephrine. Epinephrine acts as a vasoconstrictor, slowing absorption and allowing higher total doses.
How Lidocaine Dose is Calculated
The maximum allowable dose in mg is calculated as: Dose (mg) = Max per kg × Patient weight (kg). For example, a 70 kg patient receiving lidocaine without epinephrine: 4.5 × 70 = 315 mg maximum. To convert to volume: Volume (mL) = Dose (mg) ÷ (Concentration % × 10). For 1% lidocaine (10 mg/mL), 315 mg ÷ 10 mg/mL = 31.5 mL maximum volume.
Regional Notes
India: Lidocaine is widely available as Lignocaine (xylocaine). Common brands include AstraZeneca's Xylocaine and Neon Laboratories' Lignocaine. Maxilox brand is used in dental clinics. The Drugs Controller General of India (DCGI) regulates local anesthetic use. Available concentrations include 0.5%, 1%, and 2% for injection.
United States: Lidocaine is FDA-approved and available under the brand name Xylocaine (Akorn). The American Society of Regional Anesthesia and Pain Medicine (ASRA) publishes guidelines on local anesthetic toxicity management. Concentrations from 0.5% to 2% are most common for infiltration, with 1% being the standard for most procedures.
United Kingdom: Lidocaine hydrochloride is available as Xylocaine and generic preparations via the NHS. The Association of Anaesthetists of Great Britain and Ireland (AAGBI) provides safety guidelines. Maximum dosing follows the same weight-based formulas. Lipid emulsion therapy (Intralipid 20%) should be immediately available when administering lidocaine for its role in reversing local anesthetic toxicity.
Frequently Asked Questions
How is the maximum lidocaine dose calculated?
The maximum allowable subcutaneous lidocaine dose is calculated based on patient weight: 4.5 mg/kg without epinephrine and 7 mg/kg with epinephrine. The volume is then calculated by dividing the dose in mg by the concentration in mg/mL (concentration % × 10).
What is the difference between lidocaine with and without epinephrine?
Epinephrine is a vasoconstrictor that slows the absorption of lidocaine into the bloodstream, allowing a higher maximum dose (7 mg/kg vs 4.5 mg/kg) and prolonging the anesthetic effect. It also reduces bleeding at the injection site.
What are common lidocaine concentrations?
Common lidocaine concentrations include 0.25%, 0.5%, 1%, 1.5%, and 2%. Higher concentrations like 3% and 4% are used for specific procedures. A 1% solution contains 10 mg/mL of lidocaine. Lower concentrations provide larger volume for the same dose.
What are the signs of lidocaine toxicity?
Lidocaine toxicity symptoms include perioral numbness, metallic taste, drowsiness, slurred speech, muscle twitching, seizures, and in severe cases, cardiac arrhythmias, hypotension, and cardiac arrest. CNS symptoms typically appear before cardiovascular effects.
What is the maximum lidocaine dose for children?
For children, the same weight-based dosing applies: 4.5 mg/kg without epinephrine and 7 mg/kg with epinephrine. However, careful weight-based calculation is even more critical in pediatric patients due to their lower body mass and increased risk of toxicity.
Can lidocaine be used during pregnancy?
Lidocaine is classified as FDA Pregnancy Category B and is generally considered safe for use during pregnancy, including epidural anesthesia during labor. However, doses should be minimized and administered by qualified healthcare professionals. Lidocaine with epinephrine should be used cautiously due to potential effects on uterine blood flow.
How long does lidocaine anesthesia last?
Plain lidocaine typically provides anesthesia for 30–60 minutes depending on the injection site and dose. Lidocaine with epinephrine can extend the duration to 2–6 hours due to reduced vascular absorption. The duration is shorter in highly vascularized areas.
Who should not receive lidocaine?
Lidocaine is contraindicated in patients with hypersensitivity to amide-type local anesthetics, severe liver disease, methemoglobinemia, certain heart conditions including heart block and Adams-Stokes syndrome, and in patients with uncontrolled epilepsy.