Phospodiesterases are responsible for the dismantling of the intracellular messengers cyclic adenosine mono phosphate (cAMP) and cyclic guanosine monophosphate (cGMP), which are activated by nitrogen monoxide. Nonspecific inhibitors are the methylxanthines like caffeine.
cGMP is responsible for the relaxation of the blood vessels. By the specific inhibition of the dismantling of phosphodiesterase type 5 the concentration of cGMP increases. The vessel-extending effect is used in particular for the disease pictures of ertiles dysfunction (or as life style medicine for potency increasement) and pulmonary arterial hypertonia. The different commercial preparations differ in particular in their half-life.
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Sildenafil1-{[3-(1-Methyl-7-oxo-3-propyl-6,7-dihydro-1H-pyrazolo[4,3-d]pyrimidin-5-yl)-4-ethoxyphenyl]sulfonyl}-4-methylpiperazine, C28H38N6O11S, M=474,58 g/mol |
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Tadalafil(6R,12aR)-6-(1,3-Benzodioxol-5-yl)-2-methyl-1,2,3,4,6,7,12,12a-octahydropyrazino[2,1:6,1]pyrido[3,4-b]indol-1,4-dione, C22H19N3O4, MW 389,40 g/mol |
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Vardenafil1-{[3-(5-Methyl-4-oxo-7-propyl-3,4-dihydroimidazo[5,1-f][1,2,4]triazin-2-yl)-4-ethoxyphenyl]sulfonyl}-4-ethylpiperazine, C23H34N6O4S, MW 488,60 g/mol |
