Erectile Dysfunction (ED, Impotence) (cont.)

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Vardenafil (Levitra)

What is vardenafil (Levitra)?

Vardenafil (Levitra) was the second oral medicine approved by the U.S. FDA for the treatment of erectile dysfunction. Like sildenafil (Viagra), vardenafil (Levitra) inhibits PDE5 which destroys cGMP (as discussed earlier).

How effective is vardenafil (Levitra)?

Vardenafil was evaluated in four multicenter, randomized, placebo-controlled trials involving more than 2,400 men (78% white, 7% black, 2% Asian, 3% Hispanic) with erectile dysfunction. Two of these trials were conducted in special erectile dysfunction populations; one in men with diabetes mellitus, another in men who developed erectile dysfunction after prostate surgery. The doses of vardenafil in the four studies were 5 mg, 10 mg, and 20 mg.

In all four studies, vardenafil was significantly better than placebo in improving men's ability to achieve and maintain erections in all age categories (less than 45, 45-65, and greater than 65 years of age) and in all races.

How should vardenafil (Levitra) be administered?

The recommended starting dose of vardenafil is 10 mg taken orally approximately one hour before sexual activity. The dose may be adjusted higher or lower depending on efficacy and side effects. The maximum recommended dose is 20 mg, and the maximum recommended dosing frequency is no more than once per day. Vardenafil can be taken with or without food.

What are the side effects of vardenafil (Levitra)?

Vardenafil is generally well tolerated with only mild side effects. These side effects include headache, flushing, nasal congestion, dyspepsia, body aches, dizziness, nausea, and increased blood levels of the muscle enzyme creatine kinase.

There have been rare reports of priapism (prolonged and painful erections lasting more than six hours) with the use of oral PDE5 inhibitors such as vardenafil, sildenafil, and tadalafil. Men with blood cell diseases such as sickle cell anemia, leukemia, and multiple myeloma have higher than normal risks of developing priapism. Untreated priapism can cause injury to the penis tissue and lead to permanent loss of potency. If there is prolonged erection (longer than four hours), immediate medical assistance should be sought.

Who should not use vardenafil (Levitra)?

Vardenafil (Levitra) can cause hypotension (abnormally low blood pressure, which can lead to fainting and even shock) when given to patients who are taking nitrates. People taking nitrates daily should not take vardenafil. Most commonly used nitrates are medications to relieve angina (chest pain due to insufficient blood supply to heart muscle because of narrowing of the coronary arteries). These include nitroglycerine tablets, patches, ointments, sprays, pastes, and isosorbide dinitrate and isosorbide mononitrate. Other nitrates such as amyl nitrate and butyl nitrate are found in some recreational drugs called "poppers."

Vardenafil should not be used with alpha-blockers, medicines used to treat high blood pressure and benign prostate hypertrophy (BPH), because the combination of vardenafil and an alpha-blocker may lower the blood pressure greatly and lead to dizziness and fainting. Examples of alpha-blockers include tamsulosin (Flomax), terazosin (Hytrin), doxazosin (Cardura), alfuzosin (Uroxatral), and prazosin (Minipress).

Men with a rare heart condition known as long QT syndrome should not take vardenafil since this may lead to abnormal heart rhythms. The QT interval is the time it takes for the heart's muscle to recover after it has contracted. The QT interval is measured with an electrocardiogram (EKG). Some people have longer than normal QT intervals, and they may develop potentially life-threatening abnormal heart rhythms, especially when given certain medications. Since long QT syndrome can be inherited, men with a family history of long QT syndrome should not take vardenafil. Furthermore, vardenafil is not recommended for men who are taking medications that can affect the QT interval such as quinidine (Quinaglute, Quinidex), procainamide (Pronestyl; Procan-SR; Procanbid), amiodarone (Cordarone), and sotalol (Betapace).

There is insufficient information on the safety of vardenafil in men with the following conditions:

  • unstable angina (chest pain due to coronary artery disease that occurs at rest or with minimal physical exertion),
  • low blood pressure (a resting systolic blood pressure less than 90mm Hg),
  • uncontrolled high blood pressure (greater than 170/110 mm Hg),
  • recent stroke or heart attack (within six months),
  • uncontrolled, potentially life-threatening abnormal heart rhythms,
  • severe liver disease,
  • severe kidney failure requiring dialysis,
  • severe heart failure or disease of the heart's valves, for example, aortic stenosis,
  • retinitis pigmentosa.

Therefore, men with these conditions should not use vardenafil without having these conditions evaluated and stabilized first. For example, men with uncontrolled high blood pressure should have their blood pressure controlled; and men with potentially life-threatening abnormal heart rhythms should have these rhythms controlled.

When there is angina or heart failure, the doctor may need to determine whether the heart has enough reserve to safely carry out the work necessary for sexual activity by performing cardiac treadmill stress testing.

What precautions should be taken when using vardenafil (Levitra)?

Metabolism (breakdown) of vardenafil can be slowed by aging, liver disease, and concurrent use of certain medications (such as erythromycin, ketoconazole [Nizoral], and protease inhibitors). Slowed breakdown allows vardenafil to accumulate in the body and potentially increase the risk for side effects. Therefore, in men over 65 years of age, with liver dysfunction, or who are also taking medication(s) that can slow the breakdown of vardenafil, the doctor will initiate vardenafil at low doses to avoid its accumulation. For example:

  • Men taking erythromycin or ketoconazole should not take more than 5 mg of vardenafil in a 24-hour period.
  • Men taking high doses of ketoconazole (Nizoral) should not take more than 2.5 mg of vardenafil in a 24-hour period.
  • Men with moderately severe liver disease also should not take more than a 5 mg dose of vardenafil in a 24-hour period.
  • Men taking the protease inhibitor (for the treatment of HIV/AIDS) indinavir (Crixivan) should not take more than 2.5 mg of vardenafil in a 24-hour period.
  • Men taking another protease inhibitor ritonavir (Norvir) should not take more than 2.5 mg of vardenafil every 72 hours.
Medically Reviewed by a Doctor on 4/3/2014

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