Tadalafil is a major erectile dysfunction medicine that works by increasing the availability of cGMP in the body – this in turn improves blood flow to the penis. Like Sildenafil, it is classed as a PDE5 inhibitor, but has a longer half-life – tests have shown Tadalafil to operate for up to 17 hours, as opposed to Sildenafil, which has been tested at around 5 hours.
