The present invention relates to compounds of formula (I) or pharmaceutically acceptable salt, solvate or hydrate thereof, wherein R1 is C1-C3alkyl optionally substituted with F, C3-C6cycloalkyl, C1-C3alkoxy; X represents a bond or C1-C3alkylene optionally substituted with OH, ONO, ONO2; R2 is H, OH, ONO, ONO2, C(O)OH, C(O)OC1-C3alkyl, CHO, CN, C1-C3alkoxy, OC(O)H, OC(O)-C1-C3alkyl, C(O)N(R6)OR7, OC1-C3alkylene-C(O)OH, OC1-C3alkylene-C(O)OC1-C3alkyl, OC1-C3alkylene-C(0)N(R6)OR7, S(O0-2)C1-C3alkyl, CR8=N-OR9, CR8=N-NR10R11, CR8=NR12 or CR8=N-ONO2; R3 is C1-C6alkyl optionally substituted with F, OH, ONO, ONO2, C1-C3alkoxy, C3-C6cycloalkyl; C3-C6cycloalkyl, C2-C6alkenyl, C2-C6alkynyl; R4 is C1-C6alkyl optionally substituted with C3-C6cycloalkyl, C1-C6alkoxy, F, ONO, ONO2; C2-C6alkenyl, C2-C6alkynyl, C3-C6cycloalkyl; R5 is H, SO2NR13R14, NHSO2NR13R14; R6 is H or C1-C3alkyl; R7 is H, C1-C3alkyl, C1-C3alkoxy, C1-C3alkyl substituted with phenyl, benzyl or a heterocyclic ring, wherein said phenyl, benzyl or said heterocyclic ring are independently optionally substituted by C1-C3alkyl, F; R8 is H, CH3 or C2H5; R9: H, C1-C3alkyl optionally substituted with OH, ONO, ONO2, CN, COOH, COOC1-C3alkyl, C1-C3alkoxy, OC(O)H, OC(O)-C1-C3alkyl, C(O)N(R6)OR7, OC1-C3alkylene-C(O)OH, OC1-C3alkylene-C(O)OC1-C3alkyl, OC1-C3alkylene-C(O)N(R6)OR7, S(O0-2)C1-C3alkyl; R10 and R11 are each independently H, C1-C3alkyl optionally substituted with OH, ONO, ONO2, CN, COOH, COOC1-C3, C1-C3alkoxy, OC(O)H, OC(O)-C1-C3alkyl, C(O)N(R6)OR7, OC1-C3alkylene-C(O)OH, OC1-C3alkylene-C(O)OC1-C3alkyl, OC1-C3alkylene-C(O)N(R6)OR7, S(O0-2)C1-C3alkyl;i or together with the nitrogen atom to which they are attached form a heterocyclic ring, wherein preferably said heterocyclic ring is selected from aziridine, azetidine, pyrollidine, piperidine, morpholine, piperazine and homopiperazine, wherein said heterocyclic ring is optionally substituted with C1-C3 alkyl; R12 is C1-C3 alkyl optionally substituted with OH, ONO, ONO2, CN, COOH, COOC1-C3alkyl, C1-C3alkoxy, OC(O)H, OC(O)-C1-C3alkyl, C(O)N(R6)OR7, OC1-C3alkylene-C(O)OH, OC1-C3alkylene-C(O)OC1-C3alkyl, OC1-C3alkylene-C(O)N(R6)OR7, S(O0-2)C1-C3alkyl; R13 and R14 are each independently H or C1-C6alkyl optionally substituted with F, OH, ONO, ONO2, COOH, C1-C3alkoxy, C3-C6Cycloalkyl; or together with the nitrogen atom to which they are attached form a heterocyclic ring, wherein preferably said heterocyclic ring is selected from aziridine, azetidine, pyrollidine, piperidine, morpholine, piperazine, homopiperazine, 2,5-diazabicyclo[2,2,1]heptane and 3,7-diazabicyclo[3,3,0]octane, wherein said heterocyclic ring is optionally substituted with R15; R15 is C1-C6alkyl optionally substituted with halogen, OH, ONO, ONO2, C1-C3alkoxy, C1-C3haloalkoxy, COOR16, NR17R18, C=NR19, or with a tetrazole group which is optionally substituted with C1-C3alkyl; or a heteroaryl ring which is optionally substituted with F, wherein the at least one heteroatom of said heteroaryl ring is nitrogen; R16 is H, or C1-C4alkyl optionally substituted with F, OH, ONO, ONO2, NR17R18, or with a heteroaryl ring, wherein the at least one heteroatom of said heteroaryl ring is nitrogen, and wherein preferably said heteroaryl ring is selected from pyrrolidine, piperidine, piperazine, morpholine, pyrrole, and imidazole, wherein nitrogen atom is directly bound to C1-C4 alkyl; R17 and R18 are each independently H or C1-C4alkyl optionally substituted with ONO, ONO2; R19 is C1-C4alkyl optionally substituted with F, ONO, ONO2; C3-C6Cycloalkyl; and their use in methods of treating or preventing a disease alleviated by inhibition of PDE-5 in a human or in a non-human mammal.