Equivalent Concentration of Ropivacaine to Bupivacaine 0.125%
Ropivacaine 0.1% is equivalent to bupivacaine 0.125% based on the relative potency ratio of 0.8:1 (ropivacaine:bupivacaine). 1
Potency Ratios Between Local Anesthetics
- The intrathecal analgesic potency ratio of ropivacaine compared to bupivacaine is approximately 0.65, meaning ropivacaine is less potent than bupivacaine at equal concentrations 1
- For epidural anesthesia, studies suggest that ropivacaine has approximately 0.8 times the potency of bupivacaine 2, 3
- When comparing concentrations for clinical use, ropivacaine 0.2% is frequently used as an equivalent to bupivacaine 0.25% in multiple regional anesthesia applications 1
Clinical Applications and Equivalence
- In pediatric regional anesthesia guidelines, ropivacaine 0.2% is consistently paired with bupivacaine 0.25% for various nerve blocks and epidural anesthesia 1
- For thoracic epidural blocks, bupivacaine 0.25% and ropivacaine 0.2% are used interchangeably with the same volume dosing (0.2-0.3 ml/kg) 1
- For lumbar epidural blocks, bupivacaine 0.25% and ropivacaine 0.2% are administered at the same volume (0.5 ml/kg) 1
- For peripheral nerve blocks, maximum recommended doses are bupivacaine 0.25% at 1 ml/kg (2.5 mg/kg) versus ropivacaine 0.2% at 1.5 ml/kg (3 mg/kg) 4
Concentration Conversion
- When converting from bupivacaine 0.125% to an equivalent concentration of ropivacaine, the concentration should be reduced by approximately 20% 2, 3
- Therefore, ropivacaine 0.1% would provide similar analgesic efficacy to bupivacaine 0.125% 1
- For continuous infusions, bupivacaine 0.125% is often substituted with ropivacaine 0.1% to achieve similar analgesic effects with potentially reduced motor blockade 2
Clinical Advantages of Ropivacaine
- Ropivacaine produces less motor blockade at equipotent analgesic concentrations compared to bupivacaine 2
- Ropivacaine has a better safety profile with reduced cardiotoxicity compared to bupivacaine, which may be important when using larger volumes 2
- Ropivacaine has a faster onset of sensory block in some applications, though this advantage is not consistent across all studies 5, 6
Practical Considerations
- When switching from bupivacaine 0.125% to ropivacaine, using a concentration of 0.1% will provide similar analgesic efficacy 1, 2
- For procedures requiring more dense blocks, ropivacaine concentrations may need to be increased to 0.2% to match the effects of bupivacaine 0.25% 1
- The duration of sensory blockade is generally similar between equipotent concentrations of ropivacaine and bupivacaine 6