How to Calculate Lidocaine Subcutaneous Dose

This calculator determines the maximum allowable subcutaneous (subQ) dose of lidocaine (without epinephrine) based on patient weight and concentration, using these guidelines:

Maximum Dose (mg):

Maximum Volume (mL):

Where:

• Weight: Patient’s weight in kg (minimum 1 kg).
• Concentration: Lidocaine concentration in % (0.25%, 0.5%, 0.75%, 1%, 1.5%, 2%, 3%, or 4%), corresponding to mg/mL (e.g., 0.25% = 2.5 mg/mL).

The maximum single dose of lidocaine without epinephrine is 300 mg, and the maximum subQ dose is 4.5 mg/kg.

Using the Lidocaine Dose Calculator

This tool estimates the maximum allowable subcutaneous dose of lidocaine (without epinephrine) for local anesthesia. Enter the patient’s weight (kg) and select the lidocaine concentration (0.25%–4%). Results show the maximum volume (mL), dose (mg), and a warning about the single-dose limit of 300 mg.

Example: Weight 25 kg, Concentration 0.25%:

Lidocaine Dose Calculation:
Patient's Weight: 25.0 kg
Concentration: 0.25% (2.5 mg/mL)
Max allowable subQ dose, mL: 45.0 mL
Max allowable subQ dose, mg: 112.5 mg
⚠️ This tool is for information purposes only...
            

Consult a healthcare provider before administering.

Frequently Asked Questions (FAQ)

1. What is lidocaine used for?

Lidocaine is a local anesthetic used for numbing areas during procedures, without epinephrine for subQ administration in sensitive patients.

2. How is the dose determined?

It’s based on weight (max 4.5 mg/kg) and concentration, with a single-dose limit of 300 mg without epinephrine.

3. Can lidocaine be used in children?

Yes, but dosing must be weight-based and monitored closely, with pediatric guidance from a healthcare provider.

4. What’s the difference in concentrations?

Concentrations range from 0.25% (2.5 mg/mL) to 4% (40 mg/mL), affecting the volume needed for the same dose.

5. What if I exceed the maximum dose?

Exceeding 300 mg or 4.5 mg/kg can cause toxicity (e.g., seizures, cardiac issues). Always consult a provider for safe dosing.