1-Piperidinophthalazines as cardiac stimulants

A method of treating congestive heart failure in a human subject having such condition which comprises parenterally administering to said human subject a congestive heart failure treating amount of a compound selected from the group consisting of:

• ##STR21## and a pharmaceutically acceptable acid addition salt thereof, wherein Y is selected from the group consisting of --CH.sub.2 COR.sub.1 wherein R.sub.1 is alkyl having from one to four carbon atoms or alkoxy having from one to four carbon atoms;
• --N(R.sub.2)COR.sub.3 wherein R.sub.2 is hydrogen or alkyl having from one to four carbon atoms, and R.sub.3 is alkyl having from one to four carbon atoms, alkoxy having from one to four carbon atoms, phenyl or benzyloxy;
• --N(R.sub.2)SO.sub.2 R.sub.4 wherein R.sub.2 is hydrogen or alkyl having from one to four carbon atoms and R.sub.4 is alkyl having from one to four carbon atoms, phenyl, pyridyl, benzyl or dialkoxyphenyl wherein said alkoxy has from one to four carbon atoms;
• --N(R.sub.2)--CONR.sub.5 R.sub.6 wherein R.sub.2 is hydrogen or alkyl having from one to four carbon atoms, R.sub.5 is alkyl having from one to four carbon atoms, benzyl or pyridyl and R.sub.6 is hydrogen or alkyl having from one to four carbon atoms;
• --O--CONHR.sub. 7 wherein R.sub.7 is alkyl having from one to four carbon atoms, phenyl, benzyl or pyridyl;
• hydroxy;
• alkanoyloxy having from one to four carbon atoms;
• alkoxy having from one to four carbon atoms;
• substituted alkyl wherein said alkyl has from one to five carbon atoms and said substituent is hydroxy, alkoxy having from one to four carbon atoms or --CONR.sub.2 R.sub.6 wherein R.sub.2 and R.sub.6 are each hydrogen or alkyl having from one to four carbon atoms;
• and substituted alkoxy wherein said alkoxy has from two to four carbon atoms and said substituent is hydroxy or alkoxy having from one to four carbon atoms, with the proviso that other than the alpha-carbon atoms is substituted.