Filitra 40 mg is a medication used to treat erectile dysfunction by enhancing blood flow to the penis, which helps in achieving and maintaining an erection. Sexual stimulation plays a crucial role in the effectiveness of Filitra 40 mg. When a person is sexually aroused, it triggers the release of nitric oxide in the penis, which in turn activates an enzyme called guanylate cyclase. This enzyme increases levels of cyclic guanosine monophosphate (cGMP), which relaxes the smooth muscles of the penile blood vessels, allowing them to dilate and increase blood flow into the penis. However, for Filitra 40 mg to work effectively, sexual stimulation is necessary to initiate this process. The medication alone won't cause an erection; it needs the presence of sexual arousal to enhance the natural physiological response. So, while Filitra 40 mg can help improve erectile function by increasing blood flow, sexual stimulation is still required to achieve optimal erection hardness.