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Phosphodiesterase-5 Inhibitors (PDE-5 Inhibitors) for Erection Problems and Benign Prostatic Hyperplasia

Table of Contents

Phosphodiesterase-5 Inhibitors (PDE-5 Inhibitors) for Erection Problems and Benign Prostatic Hyperplasia


Generic NameBrand Name
sildenafilRevatio, Viagra
tadalafilAdcirca, Cialis
vardenafilLevitra, Staxyn

Phosphodiesterase-5 inhibitors (PDE-5 inhibitors) are taken before you plan to be sexually active. PDE-5 inhibitors will result in an erection only if you are sexually stimulated.

How It Works

During an erection, blood fills tissue in the penis, causing it to enlarge and become stiff. The PDE-5 inhibitors relax smooth muscle, allowing the penis to fill with blood.

Why It Is Used

PDE-5 inhibitors can be used when an erection problem (erectile dysfunction) is caused by:

PDE-5 inhibitors are also used in men who have an enlarged prostate, or benign prostatic hyperplasia (BPH), to help with symptoms.

How Well It Works

All PDE-5 inhibitors are very effective in treating erection problems, no matter what is causing the erection problem.1

How well the PDE-5 inhibitors work depends on the person taking it and how much he takes. But these medicines seem to work in about 7 out of 10 men who use them for erection problems.2

The medicine needs to be taken before you plan to have sex:

PDE-5 inhibitors, such as tadalafil, may help reduce BPH symptoms in men (whether or not they have erection problems). Men have about a 5-point reduction in their symptom scores on the American Urological Association symptom index.3

Side Effects

All medicines have side effects. But many people don't feel the side effects, or they are able to deal with them. Ask your pharmacist about the side effects of each medicine you take. Side effects are also listed in the information that comes with your medicine.

Here are some important things to think about:

Call 911 or other emergency services right away if you have:

Call your doctor right away if you have:

Common side effects of this medicine include:

See Drug Reference for a full list of side effects. (Drug Reference is not available in all systems.)

What To Think About

Do not take PDE-5 inhibitors if you are taking any medicine that contains nitrates, such as nitroglycerin. This combination can lower blood pressure dangerously, possibly leading to a stroke, a heart attack, or death. If you are taking a medicine called an alpha-blocker—used to treat high blood pressure or an enlarged prostate—check with your doctor before you take a PDE-5 medicine.

It is important that you tell all of your health care providers that you take this medicine. If you need emergency medical care for a heart problem, your health care provider will need to know when you last took this medicine..

These medicines may be linked to a rare type of vision loss. If you already have eye disease or vision problems (such as cataracts, glaucoma, or retinopathy), be sure to talk with your eye doctor (ophthalmologist) before you start taking any PDE-5 inhibitors.

Do not drink alcohol to excess (for example, 5 glasses of wine or 5 shots of whiskey) when you are taking tadalafil. Large amounts of alcohol can increase your chances of getting a headache or feeling dizzy, increasing your heart rate, or lowering your blood pressure.

Talk with your doctor about whether medicines for erection problems are safe for you if you:

Sexual activity is exercise. If you have a heart condition and have not been sexually active for a while, talk with your doctor to make sure you can safely engage in sexual activity.

If you eat a high-fat meal around the time you take sildenafil or vardenafil, the medicine does not work as well as it otherwise would. So many doctors recommend you take this medicine on an empty stomach. Tadalafil works without regard to what you eat.

If you are thinking about taking PDE-5 inhibitors for erection problems, it is important to include your partner in your discussions.

PDE-5 inhibitors can be prescribed by any doctor. You do not have to see a doctor who specializes in sexual health. PDE-5 inhibitors are also available on the Internet. If you obtain the medicine through this route, you should discuss its use with your doctor.

PDE-5 inhibitors may affect fertility. If you are trying to have a child, you may want to ask your doctor about how this medicine can affect your chances of conceiving.

Taking medicine

Medicine is one of the many tools your doctor has to treat a health problem. Taking medicine as your doctor suggests will improve your health and may prevent future problems. If you don't take your medicines properly, you may be putting your health (and perhaps your life) at risk.

There are many reasons why people have trouble taking their medicine. But in most cases, there is something you can do. For suggestions on how to work around common problems, see the topic Taking Medicines as Prescribed.


Follow-up care is a key part of your treatment and safety. Be sure to make and go to all appointments, and call your doctor if you are having problems. It's also a good idea to know your test results and keep a list of the medicines you take.

Complete the new medication information form (PDF) to help you understand this medication.



  1. Agency for Healthcare Research and Quality (2009). Diagnosis and Treatment of Erectile Dysfunction. Evidence Report/Technology Assessment No. 171 [AHRQ Publication No. 08(09)-E016]. Rockville, MD: Agency for Healthcare Research and Quality. Also available online:

  2. Burnett AL (2012). Evaluation and management of erectile dysfunction. In AJ Wein et al., eds., Campbell-Walsh Urology, 10th ed., vol. 1, pp. 721–748. Philadelphia: Saunders.

  3. Liu L, et al. (2011). Phosphodiesterase-5 inhibitors for lower urinary tract symptoms secondary to benign prostatic hyperplasia: A systematic review and meta-analysis. Urology, 77(1): 123–130.

Credits for Phosphodiesterase-5 Inhibitors (PDE-5 Inhibitors) for Erection Problems and Benign Prostatic Hyperplasia

By Healthwise Staff
Primary Medical Reviewer E. Gregory Thompson, MD - Internal Medicine
Primary Medical Reviewer E. Gregory Thompson, MD - Internal Medicine
Specialist Medical Reviewer Christopher G. Wood, MD, FACS - Urology, Oncology
Specialist Medical Reviewer Christopher G. Wood, MD, FACS - Urology, Oncology
Last Revised May 14, 2012

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