Local Anesthetic Activity and Acute Toxicity of (±) −2-(N-Ethylpropylamino) −2′,6′-butyroxylidide, a New Long-Acting Agent

This paper is concerned with the local anesthetic activity and acute toxicity of (±)−2-(N-ethylpropylamino)−2′,6′-butyroxylidide (I). Testing in rat sciatic nerve blocks and guinea pig intradermal wheals showed that the compound has rapid onset, excellent frequency, and long durations of block. These observations were confirmed in studies of peridural anesthesia in the cat in which the durations of block were comparable to those of the long-acting agent bupivacaine. Although the compound is more irritating and more toxic than lidocaine, it is not more so than bupivacaine and tetracaine. These studies indicate that the overall pharmacological and toxicological profile of Compound I more closely resembles those of bupivacaine and tetracaine than that of lidocaine.