The invention relates to medicine and specifically to pharmacology, and regards novel chemical compounds of general formula (I) or pharmaceutically acceptable salts, hydrates or solvates thereof, in which Rp, Rm, RA, RB Rx, R1, R2, R3 and R4 have values indicated in the description, and which are P-glycoprotein inhibitors. The present compounds may be used in the treatment of diseases of the central nervous system, and of infectious, allergic, autoimmune, oncological and other diseases. Specifically, the present compounds may be used for suppressing multiple drug resistance in patients receiving various medications over extended periods.