A 1,4-dihydropyridine derivative of the formula ##STR92## in which R and R.sub.1 each independently is hydrogen, C.sub.1 -C.sub.4 -alkyl, C.sub.1 to C.sub.12 -alkoxy, C.sub.1 -C.sub.4 -halogenoalkoxy, halogen, nitro, trifluoromethyl, ##STR93## X is oxygen or sulphur, R.sub.4 and R.sub.5 each independently is hydrogen, C.sub.1 -C.sub.4 -alkyl, C.sub.1 -C.sub.6 -alkoxy, halogen, trifluoromethyl, amino or nitro, and
- R.sub.2 and R.sub.3 each independently is hydrogen, a C.sub.1 -C.sub.10 -alkyl, C.sub.2 -C.sub.10 -alkenyl or C.sub.3 -C.sub.10 -alkinyl radical which is optionally substituted by halogen, hydroxyl, C.sub.1 -C.sub.4 -alkoxy, amino, mono- and di-C.sub.1 -C.sub.4 -alkylamino, carbo-C.sub.1 -C.sub.6 -alkoxy and/or nitro, a C.sub.3 to C.sub.6 -membered cycloalkyl radical, a phenyl radical which is optionally substituted by C.sub.1 -C.sub.4 -alkyl, C.sub.1 -C.sub.6 -alkoxy, halogen, amino and/or nitro, or a phenyl-C.sub.1 -C.sub.3 -alkyl radical, or a monosaccharide or 1-deoxynojirimycin radical which is optionally bonded via a C.sub.1 -C.sub.8 -alkyl chain to the amide nitrogen atom,
- or a pharmaceutically acceptable acid addition salt thereof, which exhibits positive inotropic activity.