Pharmacological properties of a new local anaesthetic, carbisocaine.

During the systematic analysis of the relationship between chemical structure and local anaesthetic activity of basic esters of alkoxyphenylcarbamic acids, the diethylamino-isopropylester of 2-heptyloxyphenylcarbamic acid (carbisocaine) was synthesised and later extensively studied. This drug has been shown to be as active as procaine in skin anaesthesia in molar concentrations 416 times lower, and in corneal anaesthesia the drug parallels the standard agent cocaine in molar concentrations 251 times lower. The high relative local anaesthetic potency of carbisocaine and its low subcutaneous toxicity prompted wider pharmacological investigations in which the effects of carbisocaine on the central nervous system and the circulation were studied. The experiments showed that carbisocaine produced the typical effects of a local anaesthetic drug, i.e., stimulation of central nervous system, hypotension and a drop in the heart rate. The range of toxic doses and the cytotoxic activity of this interesting compound were also established.