FIELD: medicine, pharmaceutics.SUBSTANCE: invention relates to compounds of formula (I) and their pharmaceutically acceptable salts, possessing antagonistic activity with respect to P2X3- and/or P2X2/3-receptor. In formula Ra, Rb and Rc represent (a) Ra and Rb, taken together, represent =Z； =Z represents =O； Rc stands for group, represented by R1c； R1c represents hydrogen, substituted or non-substituted C1-8alkyl, C2-8alkenyl, C3-7cycloalkyl； or (b) Rb and Rc together form bond； Ra stands for group, represented by group -Y-R1a； R1a represents substituted or non-substituted C1-12alkyl, benzyl； -Y- represents -O-, -S-, -N(R7)- or -CH2-； R7 represents hydrogen, substituted or non-substituted C1-8alkyl or R7 and R1a together form substituted with oxogroup 5-membered nitrogen-containing non-aromatic heterocyclic group； n represents integer number, equal 1 or 2； R2 represents substituted or non-substituted C3-7cycloalkyl, substituted or non-substituted phenyl or substituted or non-substituted 5-6-membered heteroaryl, containing one heteroatom, selected from N and S； R3 represents group, represented by formula: where A ring represents C3-7cycloalkyl； 6-membered non-aromatic heterocyclic group, containing 1-2 heteroatoms, independently selected from N and O； phenyl； 5-6-membered heteroaryl, containing 1-2 heteroatoms, independently selected from N and O, substituted with oxogroup 9-membered heteroaryl, containing 1-2 heteroatoms, independently selected from N and O； s represents integer number from 0 to 2； values of the remaining radicals are presented in invention formula. Invention also relates to pharmaceutical composition, to application of compounds in obtaining medication for treatment and/or prevention of disease, associated with P2X3- and/or P2X2/3-receptor, and to method of treating and/or prevention of disease, associated with P2X3- and/or P2X2/3-receptor.EFFECT: obtained are compounds, which can be used in treatment and/or prevention of diseases, associated wit
