Sildenafil - How long after taking 100mg before sex?

When I begin to feel slightly warm and flushed, usually some nasal stuffiness ,which is usually between 30 - 60 minutes after taking Sildenafil, a strong erection will accompany arousal. I find the ease of obtaining and maintaining an erection continues strongly for around 4 - 6 hours with some residual effect for around 24 hours.

I have found out I have a n erection within 45 min. of taking Sildenafil Citrate.