Synthesis of Some Nefopam Analogues as Potential Analgesics

Some derivatives of the non-narcotic analgesic nefopam containing amidine and guanidine substituents have been prepared and their analgesic activity assessed by their ability to block the uptake of noradrenaline. The compounds have been shown to inhibit noradrenaline uptake but they also display possible α1 antagonist activity at higher concentration. An ester derivative was also active and was more selective as it did not exhibit α1 adrenoreceptor antagonism.