Sildenafil boosts the impact of NO by inhibiting phosphodiesterase kind 5 (PDE5), which can be accountable for degradation of cGMP while in the corpus cavernosum. Sildenafil has no immediate relaxant impact on isolated human corpus cavernosum.5 hours. There was 1 subject with a lessen from baseline in standing systolic BP > 30mmHg subsequent VIAGRA