Local Anesthetic Calculator
Calculate maximum safe doses for multiple local anesthetics with comprehensive safety guidelines
Calculate Maximum Local Anesthetic Dose
Patient body weight for dose calculation
Different anesthetics have varying potency and duration
Higher concentrations provide deeper anesthesia but higher toxicity risk
Epinephrine increases maximum safe dose and prolongs duration
Critical Medical Warning
This calculator provides maximum safe dosing guidelines for subcutaneous administration only. Local anesthetic toxicity can be life-threatening. Always verify calculations and consult official prescribing information. Consider patient factors, injection site, and clinical conditions.
Local Anesthetic Comparison
| Anesthetic | Max Dose (mg/kg) | Max Single (mg) | Onset | Duration | Potency |
|---|---|---|---|---|---|
| Lidocaine | 4.5 | 300 | 2-5 minutes | 30-120 minutes | Low |
| Bupivacaine | 2 | 175 | 5-10 minutes | 2-6 hours | High |
| Mepivacaine | 4.4 | 400 | 3-5 minutes | 90-180 minutes | Medium |
| Ropivacaine | 3 | 225 | 5-15 minutes | 2-6 hours | High |
| Procaine | 8 | 600 | 2-5 minutes | 30-60 minutes | Low |
| Articaine | 4 | 300 | 1-3 minutes | 60-120 minutes | Medium |
* Values shown are for solutions without epinephrine
Anesthetic Toxicity Signs
Early CNS Signs
Tinnitus, metallic taste, perioral numbness, confusion
Severe CNS
Seizures, loss of consciousness, respiratory depression
Cardiovascular
Hypotension, bradycardia, arrhythmias, cardiac arrest
Allergic Reactions
Rash, urticaria, bronchospasm, anaphylaxis (rare)
Clinical Tips
Use lowest effective concentration to minimize toxicity risk
Wait for onset before assuming inadequate block
Consider ultrasound guidance for deep or high-risk injections
Have lipid emulsion (20%) available for severe toxicity
Document injection site, volume, and concentration
Understanding Local Anesthetic Dosing
Dosing Principles
Local anesthetic dosing is calculated based on patient weight and the specific properties of each anesthetic agent. The maximum safe dose is determined by both weight-based calculations and absolute maximum limits to prevent systemic toxicity.
Calculation Methods
Basic Formula:
Max dose (mg) = Weight (kg) × Max dose per kg
Volume (mL) = Max dose (mg) ÷ Concentration (mg/mL)
Safety Limits:
Use lower of: weight-based dose OR absolute maximum
Anesthetic Selection
Short Procedures:
Lidocaine, Procaine (30-120 minutes)
Long Procedures:
Bupivacaine, Ropivacaine (2-8 hours)
Cardiac Risk:
Prefer Ropivacaine over Bupivacaine
Clinical Pearl: Epinephrine not only increases maximum safe doses but also provides hemostasis and prolongs duration. However, avoid in areas with end-artery circulation (fingers, toes, nose, ears, penis).