fenpiverinium fenpiverinium fenpiverinium is an anticholinergic and antispasmodic compound; it is marketed as a combination drug with pitofenone hydrochloride and either nimesulide or metamizole in eastern europe and india to treat smooth muscle spasms and pain. fenpiveriniumclinical dataatc codea03ab21 (who) identifiers iupac name 1-(4-amino-4-oxo-3,3-diphenylbutyl)-1-methylpiperidinium cas number258329-46-3 ypubchem cid71490chemspider64566uniikp2l8lc73bcomptox dashboard (epa)dtxsid7048376 chemical and physical dataformulac22h29n2o+molar mass337.487 g·mol−13d model (jsmol)interactive image smiles c1(ccccc1)ccc(c2=cc=cc=c2)(c3=cc=cc=c3)c(=o)n inchi inchi=1s/c22h28n2o/c1-24(16-9-4-10-17-24)18-15-22(21(23)25,19-11-5-2-6-12-19)20-13-7-3-8-14-20/h2-3,5-8,11-14h,4,9-10,15-18h2,1h3,(h-,23,25)/p+1key:qdiyjdpbmzuzeh-uhfffaoysa-o (verify) the combination with metamizole was removed from the market in lithuania for safety reasons in 2000 and a boxed warning against use by children and adolescents was added in serbia in 2005. in 2016 india banned marketing of the combination with nimesulide along with 344 other combination drugs; the order was overturned in december and appealed by the government in january 2017.