11 alpha -Amino-androstanes

(I) wherein R1 is a C1-8 alkyl group or a C3-7 cycloalkyl group; R2 is a hydrogen atom, a C1-6 alkoxy group or a C2-5 alkanoyloxy group; R3 is a C1-6 alkyl group or a C3-7 cycloalkyl group; and R4 is a group -OR5 or -OCOR6 where R5 is an optionally substituted alkyl or alkenyl group which may contain up to 6 carbon atoms, an optionally substituted C3-7 cycloalkyl group, a phenyl group or a carbon-attached 5-7 membered heterocyclic ring in which the hetero-atom is selected from nitrogen, oxygen and sulphur, and R6 is a hydrogen atom or a group R5 as defined above; provided that when the compounds contain a 5 beta -hydrogen atom, R2 is a hydrogen atom and salts thereof, which compounds have activity as antidysthythmic agents.