Optionally substituted (1- or 3-oxy)-4,5,7,8-tetrahydro-(optionally 4-oxo, 4-thioxo or 4-imino)-2H-imidazo[1,2-a]pyrrolo[3,4-e]pyrimidine or (1- or 3-oxy)-4,5,7,8,9-pentahydro-(optionally 4-oxo, 4-thioxo or 4-imino)-2H-pyrimido[1,2-a]pyrrolo[3,4-e]pyrimidine compounds, processes for their production, their use as pharmaceuticals and pharmaceutical compositions comprising the same.