From the FDA Drug Label
These doses may be repeated up to once every three hours. The minimum time interval to repeat bupivacaine 2 milligrams/kilogram (mg/kg) for regional anesthesia is three hours 1.
From the Research
Bupivacaine 2mg/kg for regional block should not be repeated for at least 3-4 hours, as the most recent and highest quality study 2 suggests that increasing the volume of bupivacaine can provide more effective analgesia without side effects. The maximum recommended dose in a 24-hour period is typically 400mg for adults (or 5-6mg/kg total daily dose) as indicated by older studies 3. When considering redosing, it's essential to account for the long duration of action of bupivacaine, which can last 4-12 hours depending on the specific formulation and site of injection. Some key points to consider when using bupivacaine for regional anesthesia include:
- Patient factors such as age, weight, liver function, and cardiovascular status, which affect drug metabolism and clearance 4.
- The risk of systemic toxicity, which can manifest as central nervous system effects (seizures) and cardiovascular toxicity (hypotension, arrhythmias, cardiac arrest) 5.
- The potential benefits of using a continuous catheter technique rather than repeated bolus injections, or switching to a different local anesthetic with a better safety profile for repeated dosing 6. It's also important to note that the most recent study 2 found that using 0.25% bupivacaine in a volume of 0.5 mL/kg provided more effective analgesia than lower volumes, without any side effects. However, this study did not specifically address the minimum time interval for repeating bupivacaine doses. Given the potential risks and benefits, the minimum time interval for repeating bupivacaine 2mg/kg for regional anesthesia should be at least 3-4 hours, and patient factors and individual response to the medication should be carefully considered when determining the optimal dosing schedule 2.