Pharmacy Author: Omudhome Ogbru, Pharm.D.
Medical Editor: Jay Marks, M.D.

GENERIC NAME: vardenafil

BRAND NAME: Levitra

DRUG CLASS AND MECHANISM: Vardenafil is an oral drug that is used to treat impotence (the inability to attain or maintain a penile erection.). 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.

PRESCRIPTION: Yes

GENERIC AVAILABLE: No

PREPARATIONS: Tablets: 2.5, 5, 10 and 20 mg

STORAGE: Vardenafil should be stored at room temperature between 15-30°C (59-86°F).

PRESCRIBED FOR: Vardenafil is used for the treatment of impotence.

DOSING: For most individuals, the recommended dose of vardenafil is 10 mg per day taken 60 minutes before intercourse. If there is no response or side effects, the dose may be increased to 20 mg or, if there are side effects, it may be reduced to 5 mg. Individuals 65 years of age or older should begin therapy with 5 mg. Individuals who are taking medications that increase the blood levels of vardenafil should start treatment with 2.5 to 5 mg of vardenafil. (See drug interactions.)

DRUG INTERACTIONS: 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.

Vardenafil reduces the concentration of ritonavir and indinavir and may reduce the effect these drugs.

Vardenafil 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.

PREGNANCY: Vardenafil is not approved for use in women.

NURSING MOTHERS: Vardenafil has not been evaluated in women who are breastfeeding.

SIDE EFFECTS: The most common side effects of vardenafil are 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).  Rare cases of sudden loss of hearing have been reported with phosphodiesterase inhibitors such as vardenafil, sometimes associated with ringing in the ears and dizziness.  If changes in hearing occur, patients should discontinue their vardenafil and seek immediate medical attention.

Last Editorial Review: 10/19/2007

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