The present invention describes new pyridopyrimidine derivatives compounds with structure represented by General Formula (I): or pharmaceutically acceptable salts thereof, or their mixtures (in any ratio), a pharmaceutical composition containing them, a method for using the new pyridopyrimidine derivatives compounds as inhibitor of the cyclic nucleotide synthesis or as inhibitor of the cAMP and cGMP synthesis, and their uses in the prophylactic and/or curative treatment of diarrhea, colitis and irritable bowel syndrome.