A Generic Sildenafil Tablet is Fildena 100mg. This high-power dosage is mostly prescribed to men with erectile dysfunction. As a result, firm erections appear in a few minutes & can last up to 5 hours. Sildenafil Citrate (a PDE-5 inhibitor) is the key component of this impotence medication. Sildenafil interferes with the cGMP cycle & dilates blood vessels in the male genitals for better erections.