Bupivacaine hydrochloride

Bupivacaine hydrochloride (Marcain) is a more potent cAMP production inhibitor with an IC50 of 2.3 uM. It more potently inhibited basal cAMP production than either ropivacaine (IC50 = 4 uM) or mepivacaine (IC50 = 32 uM). Similarly, it was as potent as ropivacaine (IC50 = 1.7 uM) and more potent than mepivacaine (IC50 = 8.9 uM) at inhibiting epinephrine-stimulated cAMP production. Bupivacaine (IC50 = 5.3 uM) was only marginally more potent than ropivacaine (IC50 = 9.7 uM) or mepivacaine (IC50 = 6.8 uM) at inhibition of forskolin-stimulated cAMP production. Comparison of epinephrine concentration-response curves in the presence and absence of bupivacaine (0.35, 3.5, and 35 uM ) demonstrated noncompetitive inhibition of cAMP production by the local anesthetic.