Take this medication by mouth . Take vardenafil, with or without food, about 1 hour before sexual activity. Do not take more than once daily. Doses should be taken at least 24 hours apart.

For most patients, the recommended starting dose of LEVITRA is 10 mg, taken orally, as needed, approximately 60 minutes before sexual activity. The dose may be increased to a maximum recommended dose of 20 mg or decreased to 5 mg based on efficacy and side effects. The maximum recommended dosing frequency is once per day. Sexual stimulation is required for a response to treatment.

During a penile erection, the penis fills with blood.

The blood vessels that supply the penis with blood expand, or dilate, and the vessels that take blood away from the penis contract. The two large chambers in the penis, known as the corpus cavernosa, fill with blood.

As the blood accumulates in the penis, an erection results.

Vardenafil belongs to a class of drugs called phosphodiesterase type-5 (PDE5) inhibitors. A PDE5 inhibitor stops PDE5 from constricting the arteries.

By relaxing the arteries, vardenafil enhances blood flow when a man is sexually aroused.

The active ingredient works on the chain of reactions within the penis during arousal.

When a male is sexually aroused, nitric oxide is released into his penis, and this triggers a chain of reactions.

This causes an enzyme, guanylate cyclase, to produce cyclic guanosine monophosphate (cGMP).

cGMP regulates the contraction and dilation, or expansion, of blood vessels that carry blood to and from the penis. The chemical reaction causes the vessels that supply the penis to dilate, while those removing blood from the penis contract.

Phosphodiesterase-5 (PDE5), another enzyme breaks down or destroys cGMP.

When cGMP is destroyed, the blood vessels return to their normal size, effectively ending the erection. Vardenafil stops PDE5 from destroying cGMP. In this way, it allows cGMP to work for longer. As a result, it helps prolong an erection.