Malegra is considered a PDE5 (phosphodiesterase type 5) inhibitor because it works by blocking the action of the enzyme PDE5. This enzyme typically breaks down cyclic guanosine monophosphate (cGMP), a molecule that plays a key role in regulating blood flow in the penis. By inhibiting PDE5, Malegra helps to maintain higher levels of cGMP, which in turn promotes the relaxation of smooth muscles and the dilation of blood vessels in the penis. This enhanced blood flow facilitates an erection in response to sexual stimulation. Malegra is commonly used to treat erectile dysfunction as it targets the underlying mechanisms that limit erectile function.