The half-life of Filitra (a brand name for the drug vardenafil) is approximately 4 to 5 hours. Filitra, an erectile dysfunction medication, works by inhibiting the enzyme phosphodiesterase type 5 (PDE5), which helps relax blood vessels in the penis and increases blood flow, allowing an erection to occur in response to sexual stimulation. The half-life refers to the time it takes for the concentration of the drug in the bloodstream to decrease by half. Because of its moderate half-life, vardenafil typically provides effects for several hours, allowing for flexibility in its usage. It is important to note that the half-life may vary slightly based on individual factors such as metabolism, liver function, and other health conditions.