ism ▁Pent obar b ital ▁under go es ▁first - pass ▁met abol ism ▁in ▁the ▁li ver ▁and ▁possibly ▁the ▁int est ines . ▁ ▁D rug ▁interactions ▁Administration ▁of ▁eth an ol , ▁ben z odia ze p ines , ▁op io ids , ▁anti h ist am ines , ▁other ▁sed ative - h yp not ics , ▁and ▁other ▁central ▁nerv ous ▁system ▁de press ants ▁will ▁cause ▁possible ▁add itive ▁effects . ▁ ▁Chem istry ▁Pent obar b ital ▁is ▁synth es ized ▁by ▁methods ▁analog ous ▁to ▁that ▁of ▁am obar b ital , ▁the ▁only ▁difference ▁being ▁that ▁the ▁alk yl ation ▁of ▁α - eth yl mal onic ▁est er ▁is ▁carried ▁out ▁with ▁ 2 - b rom op ent ane ▁in ▁place ▁of ▁ 1 - b rom o - 3 - m eth yl but ane ▁to ▁give ▁pent obar b ital . ▁ ▁Names ▁Pent obar b ital ▁is ▁the ▁IN N , ▁A AN , ▁B AN , ▁and ▁US AN ▁while ▁pent obar bit one ▁is ▁a ▁former ▁A AN ▁and ▁B AN . ▁ ▁One ▁brand ▁name ▁for ▁this ▁drug ▁is ▁N emb ut al , ▁co ined ▁by ▁John ▁S . ▁Lund y , ▁who ▁started ▁using ▁it ▁in ▁ 1 9 3 0 , ▁from ▁the ▁struct ural ▁formula ▁of ▁the ▁sod ium ▁salt — Na ▁( s od ium ) ▁+ ▁eth yl ▁+ ▁m eth yl ▁+ ▁but yl ▁+ ▁al ▁( common ▁suffix