Table 6.

Comparison of IC₅₀ values in inhibiting frog or rat sciatic nerve fast-conducting CAPs and TTX-sensitive or -resistant Na⁺ channels among local anesthetics.

Local Anesthetics	Frog CAP IC50 (mM)	Rat CAP IC50 (mM)	TTX-Sensitive Na+ Channel Current IC50 (mM)	TTX-Resistant Na+ Channel Current IC50 (mM)	References
Amide Type
Lidocaine	0.74	0.28	0.204	0.073	[19,71,148,236]
Ropivacaine	0.34	0.28			[19,236]
Prilocaine	1.8				[26]
Levobupivacaine	0.23		0.264		[23,239]
Bupivacaine	76% reduction (0.5 mM)		0.027		[23,71]
			0.178		[155]
			0.190		[204]
Ester Type
Cocaine	0.80	40% reduction (0.375 mM)		ca. 70% reduction (0.05 mM)	[20,72,244]
Procaine	2.2	ca. 1 mM	0.060		[27,71,248]
Benzocaine	0.80	37% reduction (1.3 mM)			[25,59]
Tetracaine	0.014		0.0007		[22,71]
Other Type
Pramoxine	0.21				[26]

Here, when IC₅₀ values are not available, it is partly shown for comparison how CAP and channel current amplitudes are reduced by drugs, where % value indicates the extent of the reduction at the concentration shown in parentheses.