Vardenafil is an oral drug that is used to treat impotence. It is a phosphodiesterase inhibitor
that is similar to sildenafil (Viagra). Penile erection is caused by the engorgement of the penis with blood. This engorgement occurs when the blood vessels delivering blood
to the penis increase in size and increase the delivery of blood to the penis. At the same time, the blood vessels carrying blood away from the penis decrease in size and
decrease the removal of blood from the penis. Sexual stimulation that leads to the engorgement and erection causes the production and release of nitric oxide in the penis.
Nitric oxide then activates the enzyme, guanylate cyclase to produce cyclic guanosine monophosphate (cGMP). The cGMP is primarily responsible for increasing and
decreasing the size of the blood vessels carrying blood to and from the penis, respectively. Vardenafil prevents an enzyme called phosphodiesterase-5 from destroying cGMP
so that cGMP persists longer. The longer cGMP persists, the more prolonged the engorgement of the penis.Vardenafil was approved by the FDA in August, 2003.

Most common side effects of vardenafil may include facial flushing (reddening),
headaches, stomach upset, diarrhea, flu like symptoms and nausea. Vardenafil also may cause chest pain, low blood pressure, blurred vision and changes in color vision,
abnormal ejaculation and priapism (painful erection).

Vardenafil reduces the concentration of ritonavir and indinavir and may reduce the effect these drugs.
The
breakdown and elimination of vardenafil from the body is inhibited by erythromycin, ketoconazole (Nizoral), itraconazole (Sporanox), indinavir (Crixivan) and ritonavir
(Norvir). Therefore, these drugs increase the concentration of vardenafil in the blood. If these drugs are being used at the same time as vardenafil, the dose of vardenafil
should be reduced in order to avoid side effects from vardenafil. It increases the heart rate and also exaggerates the blood pressure lowering effects of nitrates (e.g.
nitroglycerine). In patients who take nitrates for chest pain (angina), vardenafil could cause chest pain by increasing heart rate and lowering blood pressure. Therefore,
patients with angina should not use vardenafil. Vardenafil also exaggerates the blood pressure lowering effects of alpha-blocking drugs, e.g. terazosin (Hytrin), and should
not be used by individuals who also use alpha-blockers.

Recommended dose of vardenafil is 10 mg per day taken 60 minutes before intercourse. The dose may be increased to 20 mg, if there is no response or the dose may be
reduced to 5 mg, if you notice any side effects. Individuals who are taking medications that increase the blood levels of vardenafil should start treatment with 2.5 to 5 mg of
vardenafil. It should be stored at room temperature between 15-30°C (59-86°F).