From the Guidelines
The maximum safe dose of 1% lidocaine for local administration is 4.5 mg/kg of body weight, not to exceed 500 mg total dose, as recommended for a multistage procedure like Mohs micrographic surgery, which translates to about 50 mL of 1% lidocaine solution 1. When administering 1% lidocaine for local anesthesia, it is essential to:
- Use the lowest effective dose
- Inject slowly and aspirate frequently to avoid intravascular injection
- Be aware that the total dose may need to be reduced in elderly, debilitated, or acutely ill patients The recommended dose is based on the threshold for systemic toxicity, and lidocaine works by blocking sodium channels in nerve cells, preventing the propagation of action potentials. At higher systemic levels, it can affect the central nervous system and cardiovascular system, potentially causing seizures or cardiac arrhythmias. Key considerations for local anesthesia administration include:
- Monitoring the patient closely for signs of toxicity such as lightheadedness, tinnitus, or perioral numbness
- Having resuscitation equipment available when using local anesthetics
- Being mindful of the maximum safe dose for adults, which is 4.5 mg/kg of lidocaine and 7.0 mg/kg of lidocaine with epinephrine, and for children, which is 1.5-2.0 mg/kg of lidocaine and 3.0-4.5 mg/kg of lidocaine with epinephrine 1.
From the FDA Drug Label
Adults For normal healthy adults, the individual maximum recommended dose of lidocaine HCl without epinephrine 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. The maximum recommended dose per 90 minute period of lidocaine hydrochloride for paracervical block in obstetrical patients and non-obstetrical patients is 200 mg total. The maximum dose of 1% lidocaine for local administration is 300 mg for adults, and 200 mg per 90 minute period for paracervical block in obstetrical and non-obstetrical patients 2.
- The dose for pediatric patients is determined by the child's age and weight, but should not exceed 1.5 to 2 mg/lb.
- The lowest effective concentration and dose should be used to guard against systemic toxicity.
From the Research
Maximum Dose of 1% Lidocaine
The maximum dose of 1% lidocaine for local administration is a topic of debate among clinicians and researchers.
- According to 3, the common occurrence of central nervous system toxicity symptoms when large lidocaine doses were used in infiltration anesthesia led to the recommendation of just 200 mg as the maximum dose.
- However, 4 suggests that for the infiltration technique of local analgesia, 500 mg is a safe maximum for plain lignocaine and 670 mg with adrenaline, but concentrated 1% and 2% solutions should not be used for the infiltration technique.
- Additionally, 5 states that lidocaine (lignocaine) 1% with epinephrine (adrenaline) 1:200,000 has a maximum dose of 40mL.
Factors Affecting Maximum Dose
Several factors can affect the maximum dose of 1% lidocaine, including:
- Site of injection: 3 suggests that the site of local anesthetic injection can influence the effect and pharmacokinetics of the local anesthetic.
- Patient-related factors: 3 also mentions that patient-related factors such as age, organ dysfunctions, and pregnancy can influence the effect and pharmacokinetics of the local anesthetic.
- Concentration of epinephrine: 5 notes that epinephrine-induced vasoconstriction delays local anesthetic clearance, thus prolonging its effect and enabling a higher maximum dose to be used.
Specific Studies
- 6 evaluated the use of water-diluted local anesthetic for trigger-point injection in chronic myofascial pain syndrome and found that a mixture of 1% lidocaine with water in a 1:3 ratio has less injection pain and is more effective than unaltered 1% lidocaine.
- 7 compared buffered 1% lidocaine with epinephrine to nonbuffered 2% lidocaine with epinephrine for maxillary field block and found that buffered 1% lidocaine can be as effective as nonbuffered 2% lidocaine.