The relative potencies for motor block after intrathecal ropivacaine, levobupivacaine, and bupivacaine

Michela Camorcia, Giorgio Capogna, Cristiana Berritta, Malachy O Columb
Anesthesia and Analgesia 2007, 104 (4): 904-7

BACKGROUND: In this study, we sought to determine the median effective dose (ED50) for motor block of intrathecal ropivacaine, levobupivacaine, and bupivacaine and to define their motor-blocking potency ratios.

METHODS: We enrolled 104 parturients undergoing elective cesarean delivery with combined spinal-epidural anesthesia and randomized them to one of three groups to receive intrathecal 0.5% (wt/vol) ropivacaine, levobupivacaine, or bupivacaine. The initial dose was 4 mg, and the testing interval was set at 1 mg. Efficacy was determined by the occurrence of any motor block in either lower limb (modified Bromage and hip motor function scale) within 5 min after the spinal injection.

RESULTS: As assessed using up-down analysis, intrathecal ED50 for motor block was 5.79 mg for ropivacaine (95% CI 4.62-6.96), 4.83 mg for levobupivacaine (95% CI 4.35-5.32) and 3.44 mg for bupivacaine (95% CI 2.55-4.34) (P < 0.0007). The relative motor blocking potency ratios were ropivacaine/bupivacaine 0.59 (95% CI, 0.42-0.82), ropivacaine/levobupivacaine 0.83 (95% CI 0.64-1.09), and levobupivacaine/bupivacaine 0.71 (95% CI 0.51-0.98).

CONCLUSIONS: There is a clinical profile of potency for motor block for the pipecolylxylidines when administered spinally: low, intermediate, and high for ropivacaine, levobupivacaine, and bupivacaine, respectively.

Full Text Links

Find Full Text Links for this Article


You are not logged in. Sign Up or Log In to join the discussion.

Related Papers

Remove bar
Read by QxMD icon Read

Save your favorite articles in one place with a free QxMD account.


Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"