What is the recommended dosage for local anaesthetics, such as lidocaine (Lidocaine) and bupivacaine (Bupivacaine), for achieving effective anaesthesia?

From the Guidelines

The recommended dosage for local anesthetics, such as lidocaine and bupivacaine, should not exceed 4.5 mg/kg and 2.5 mg/kg, respectively, to minimize the risk of toxicity and ensure effective anesthesia. When administering local anesthetics, it is crucial to calculate the total dose based on the patient's weight to avoid toxicity. For example, in a 70 kg adult, the maximum lidocaine dose would be approximately 315 mg without epinephrine or 490 mg with epinephrine, as stated in the guidelines for the use of local anesthesia in office-based dermatologic surgery 1. The onset of action for lidocaine is relatively quick (2-5 minutes) with a duration of 1-2 hours, while bupivacaine has a slower onset (5-10 minutes) but longer duration (4-8 hours) 2. These differences in pharmacokinetics make lidocaine more suitable for shorter procedures and bupivacaine better for prolonged analgesia. Some key points to consider when using local anesthetics include:

• Always aspirate before injecting to avoid intravascular administration
• Consider using the lowest effective concentration and volume to minimize risks while achieving adequate anesthesia
• Be aware of the maximum safe doses for local anesthetics, which are 4.5 mg/kg for lidocaine without epinephrine and 7.0 mg/kg for lidocaine with epinephrine in adults, and 1.5-2.0 mg/kg for lidocaine and 3.0-4.5 mg/kg for lidocaine with epinephrine in children 3
• Use of either ester-type local anesthetics, bacteriostatic normal saline, or 1% diphenhydramine is suggested as an alternate form of local infiltration anesthesia for patients with true allergy to lidocaine 3. It is essential to follow these guidelines and consider the specific medication, procedure type, and patient factors to ensure safe and effective use of local anesthetics.

From the FDA Drug Label

The duration of anesthesia with Bupivacaine Hydrochloride is such that for most indications, a single dose is sufficient Maximum dosage limit must be individualized in each case after evaluating the size and physical status of the patient, as well as the usual rate of systemic absorption from a particular injection site Most experience to date is with single doses of Bupivacaine Hydrochloride up to 225 mg with epinephrine 1:200,000 and 175 mg without epinephrine; more or less drug may be used depending on individualization of each case. The dosages in Table 1 have generally proved satisfactory and are recommended as a guide for use in the average adult.

The recommended dosage for local anaesthetics, such as bupivacaine, varies depending on the specific procedure and the patient's physical status.

• The maximum dosage limit must be individualized for each patient.
• For most indications, a single dose is sufficient.
• The recommended dosages are: + Up to 225 mg with epinephrine 1:200,000 + Up to 175 mg without epinephrine
• These dosages may be repeated up to once every three hours, with a total daily dose not exceeding 400 mg 4.

From the Research

Local Anaesthetic Dosage

The recommended dosage for local anaesthetics, such as lidocaine and bupivacaine, varies depending on several factors, including the site of injection, patient age, and organ function.

• The maximum recommended dose of lidocaine is 200 mg, which has remained unchanged for over 50 years 5.
• However, this dose may need to be adjusted based on patient-specific factors, such as age, organ dysfunction, and pregnancy 5.
• The addition of epinephrine to the local anaesthetic solution can help reduce the risk of systemic toxicity, but its use should be carefully considered in patients with certain medical conditions 5.
• The choice of local anaesthetic and dosage also depends on the desired onset, intensity, and duration of block, as well as possible adverse effects 6.
• For example, lidocaine is suitable for longer procedures, while mepivacaine and 2-chloroprocaine are better suited for shorter procedures or day-case spinal anesthesia 6, 7.

Dosage Recommendations for Specific Local Anaesthetics

• Lidocaine: 0.5-2.0 mg/kg for local anaesthesia and attenuation of bronchial hyper-reactivity with minimal airway irritation 8.
• Bupivacaine: low-dose (e.g., 5-10 mg) for spinal anesthesia in total hip and total knee arthroplasty, but may be associated with slower and less predictable return of motor function compared to mepivacaine 7.
• Mepivacaine: may be a safer alternative to lidocaine, bupivacaine, and ropivacaine for primary cultured chick neurons, with a lower IC50 value and better reversibility of neurotoxic effects 9.

Factors Influencing Local Anaesthetic Dosage

• Patient age: older patients may require lower doses due to decreased clearance and increased sensitivity to local anaesthetics 5.
• Organ dysfunction: patients with renal, hepatic, or cardiac disease may require lower doses due to altered pharmacokinetics and increased risk of toxicity 5.
• Pregnancy: pregnant patients may require lower doses due to increased sensitivity to local anaesthetics and altered pharmacokinetics 5.
• Site of injection: the dose and volume of local anaesthetic may need to be adjusted based on the site of injection and the desired block 6.