ROPIVACAINE

ROPIVACAINE

Ropivacaine has been looked to as a potentially useful alternative
to bupivacaine, with touted advantages being a greater degree of differential
blockade and reduced potential for cardiac toxicity. Regarding the
latter, using modern techniques of labor epidural analgesia (fractionated
administration of small doses of local anesthetic / opioid solutions), the
risk of systemic toxicity, and much less cardiac toxicity, is essentially
nonexistent. Even with administration of larger doses of bupivacaine
(100 mg) for cesarean section, systemic toxicity is effectively prevented
by the use of a test dose (including markers of intravascular injection)
and fractionated administration of the therapeutic dose. Regarding differential
blockade, studies in obstetric patients have not yet borne out
any advantage of ropivacaine over bupivacaine. The two drugs produce
clinically indistinguishable analgesic effects when administered intrathecally62
or epid~ral ly6~9, ~, lo8 for labor analgesia. It is not yet clear
whether slight advantages of epidural ropivacaine over bupivacaine
with regard to mode of delivery and early neonatal behavior scores
reported by a few investigator^^^, lo8 are of any clinical significance.
Slight differences have been observed when administered epidurally for
cesarean section. At equal doses and concentrations, ropivacaine 0.5%
produced a slightly shorter duration of intense motor blockz6, 29 and
better maintained uterine artery blood flow on the placental side, compared
with bupivacaine. It remains to be determined whether there are
any clinically useful