The present invention relates to highly selective phosphodieterase (PDE) enzyme
inhibitors and to their use in pharmaceutical articles of manufacture. In particular,
the present invention relates to potent inhibitors of cyclic guanosine 3,5-monophosphate
specific phosphodiesterase type 5 (PDE5) that when incorporated into a pharmaceutical
product at about 1 to about 20 mg unit dosage are useful for the treatment of sexual dysfunction.