From the Guidelines
The maximum dose of lidocaine should not exceed 9 mg.kg-1 lean body weight. This recommendation is based on the most recent and highest quality study available, which prioritizes patient safety and minimizes the risk of toxicity 1. When administering lidocaine, it is essential to calculate the total dose based on the patient's actual weight and the concentration of lidocaine being used. For example, 1% lidocaine contains 10 mg/mL, while 2% contains 20 mg/mL.
Key Considerations
- The maximum dose of lidocaine without epinephrine is generally considered to be 4-5 mg/kg of body weight, while the maximum dose with epinephrine is 7 mg/kg 1.
- However, the most recent guideline recommends a maximum dose of 9 mg.kg-1 lean body weight, which takes into account the patient's lean body weight rather than total body weight 1.
- It is crucial to consider the patient's individual factors, such as age, weight, and medical conditions, when determining the appropriate dose of lidocaine.
- Signs of lidocaine toxicity include perioral numbness, metallic taste, dizziness, tinnitus, and in severe cases, seizures or cardiovascular collapse.
Administration and Monitoring
- Onset of action typically occurs within 2-5 minutes, and duration varies from 30 minutes to 2 hours depending on the formulation.
- Supplemental oxygen should always be administered during procedures involving lidocaine, and monitoring of vital signs is essential to quickly identify any potential toxicity.
- Effective topicalization must be established and tested before administering lidocaine, and cautious use of minimal sedation can be beneficial in some cases 1.
From the FDA Drug Label
For normal healthy adults, the maximum individual dose should not exceed 4. 5 mg/kg (2 mg/lb) of body weight, and in general it is recommended that the maximum total dose does not exceed 300 mg. For children over 3 years of age who have a normal lean body mass and normal body development, the maximum dose is determined by the child’s age and weight. For example, in a child of 5 years weighing 50 lbs the dose of lidocaine hydrochloride should not exceed 75 to 100 mg (1.5 to 2 mg/lb). The use of even more dilute solutions (i.e., 0.25 to 0.5%) and total dosages not to exceed 3 mg/kg (1. 4 mg/lb) are recommended for induction of intravenous regional anesthesia in children.
The maximum recommended dose of lidocaine per weight is:
- 4.5 mg/kg (or 2 mg/lb) for normal healthy adults 2
- 3 mg/kg (or 1.4 mg/lb) for children over 3 years of age for intravenous regional anesthesia 2
- 1.5 to 2 mg/lb for children over 3 years of age, depending on the specific situation 2
From the Research
Lidocaine Maximum Dose per Weight
- The maximum recommended dose of lidocaine varies depending on the specific application and patient factors 3, 4, 5, 6.
- For local anesthesia, the conventional dosage of lidocaine is up to 4.5 mg/kg, and that with adrenaline is up to 7 mg/kg 5.
- In some cases, such as tumescent anesthesia for liposuction, the recommended maximum dose of lidocaine with adrenaline is up to 55 mg/kg 5.
- A study on facelift procedures found that a mean lidocaine dose of 21.6 +/- 3.6 mg/kg (range, 17.5-26.3 mg/kg) was safe and effective when administered with epinephrine 6.
- Another study suggested that the total dose of lidocaine should be limited to 300-400 mg (or < 8.2 mg/kg) to minimize the risk of toxicity 3.
Factors Affecting Lidocaine Dosage
- Patient factors such as age, organ dysfunctions, and pregnancy can influence the effect and pharmacokinetics of lidocaine 4.
- The site of local anesthetic injection and the presence of epinephrine can also impact the safe dosage of lidocaine 4, 6.
- The use of epinephrine in concentrations of 2.5 to 5 microg/mL can help reduce the risk of toxicity when large doses of lidocaine are administered 4.
Safety Considerations
- Lidocaine toxicity is directly correlated with its concentration in the blood, and a threshold above which side effects become more likely has been put at a plasma level of 5 microg/ml 3.
- Monitoring for signs and symptoms of local anesthetic systemic toxicity (LAST) is crucial when administering high doses of lidocaine 5.
- Having lipid emulsion therapy readily available can be life-saving in cases of LAST 5.