The invention relates to pyridazinone and pyridone com- pounds having formula (I) or (I'), and pharmaceutically acceptable salts, hydrates, and solvates thereof (I) wherein R1 / R4 and X and X3 are as defined in the claims. The invention further relates to their use as inhibitors of copper-containing amine oxidases. The present invention also relates to the preparation of the aforementioned com- pounds and to pharmaceutical compositions comprising as an active ingredient(s) one or more of the aforementioned compounds, pharmaceutically acceptable salts, hydrates, or solvates thereof.
