From the Guidelines
The maximum safe dose of 1% lidocaine with epinephrine is 7 mg/kg of body weight, with an absolute maximum of 500 mg in adults, as recommended by the most recent guidelines 1. This dose limit is crucial to prevent toxicity and ensure patient safety. The addition of epinephrine allows for a higher maximum dose compared to plain lidocaine because it causes local vasoconstriction, slowing systemic absorption of lidocaine and reducing toxicity risk. When calculating doses, it's essential to remember that 1% lidocaine contains 10 mg of lidocaine per mL. Some key points to consider when using lidocaine with epinephrine include:
- Using the lowest effective dose
- Injecting slowly with frequent aspiration to avoid intravascular injection
- Monitoring for signs of lidocaine toxicity, such as perioral numbness, metallic taste, dizziness, tinnitus, and in severe cases, seizures and cardiovascular collapse
- Being cautious in patients with severe cardiovascular disease
- Avoiding use in areas with end-arterial circulation, such as fingers, toes, penis, and ears The most recent and highest quality study 1 provides the basis for this recommendation, and it is essential to follow these guidelines to minimize morbidity, mortality, and improve quality of life.
From the Research
Maximum Dose Limit for Local Anesthesia
- The maximum dose limit for local anesthesia using 1% lidocaine (lignocaine) with epinephrine (adrenaline) is not strictly defined, but rather depends on various factors such as the site of injection, patient age, and organ function 2.
- A study published in 1996 recommends a maximum dose of 40mL for 1% lidocaine with epinephrine 1:200,000 for skin surgery 3.
- Another study published in 2009 used a mixture of 0.5% bupivacaine and 2% lidocaine with epinephrine 1:200,000, with a total dose of 500mg of lidocaine, but this was for a specific type of nerve block and may not be applicable to all situations 4.
- A study published in 2017 used 40mg of buffered 1% lidocaine with epinephrine 1:100,000 for a maxillary field block, but this was a specific application and the dose may not be generalizable to other situations 5.
Factors Affecting Maximum Dose
- Patient factors such as age, organ dysfunction, and pregnancy can influence the maximum safe dose of local anesthetic 2.
- The site of injection and the specific procedure being performed can also affect the maximum dose limit 2, 3.
- The addition of epinephrine to the local anesthetic solution can affect the maximum dose limit, as it can reduce peak blood concentrations and prolong the duration of action 3.