Which drug for erectile dysfunction?

Harvard Men's Health Watch

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There are some potentially helpful differences between these medications, but price can limit your choices.

About half of men ages 40 to 70 have erectile dysfunction (ED) to some degree, although only one in 10 report a complete inability to have erections. Taking an ED drug produces an erection sufficient to start intercourse in about 70% of otherwise healthy men.

Does it make any difference which of the four ED drug on the market you take? "Yes, there can be differences," says Dr. Louis Liou, chief of urology at Harvard-affiliated Cambridge Health Alliance in Boston. "For new patients, I have them try different ones to see what works best."

Sildenafil (Viagra) is often the first drug your doctor offers. It's been on the market longest and its side effects and the medications and foods it interacts with are well known. The latest drug to be approved, avanafil (Stendra), may have fewer side effects than the other drugs.

But the main challenge to finding the best ED drug for you may turn out to be health insurance rules—not biochemistry. It's a common practice among insurers to limit the number of pills you can obtain per month. After you hit your limit, the out-of-pocket cost for a single pill can be as high as $20. "The main obstacle in my practice is the cost," Dr. Liou says. You'll need to work with your doctor to get the pill you need at a price you can afford.

What is available?

In addition to Viagra and Stendra, the two other ED drugs available in the United States are tadalafil (Cialis) and vardenafil (Levitra). These all improve blood supply to the penis. In combination with sexual stimulation, the drugs can produce an erection sufficient to initiate and complete intercourse. There is also a fast-dissolving form of Levitra, called Staxyn, that you put under your tongue.

One ED drug, Cialis, is FDA-approved for use daily in a dose of 2.5 or 5 milligrams. This helps to produce erections on demand and may also help relieve urinary problems, like difficulty starting urination, that result from an enlarged prostate.

How to control the cost

The cost to you for ED drug therapy varies considerably, depending on the pharmacy price, prescription co-pays, and your level of health plan coverage. Nationally, the out-of-pocket cost per pill ranges from approximately $15 to $20. Even if private insurance covers it, you may be limited to four doses per month. Here are a few things you can do to contain costs:

  • Shop around, because pharmacy prices vary. Various web-based tools can help you compare prices easily. One of them is www.goodrx.com.

  • Ask your doctor about pill splitting, where you get the pills at a higher dose than you need and divide them.

  • Explore manufacturer discount programs. These allow you to obtain a limited supply of medications not covered by your insurance.

How well do they work?

ED drugs produce an erection sufficient for intercourse in about 70% of men. But the results vary quite a bit from one individual to another. A man with nerves or arteries damaged by prostate surgery, diabetes, or cardiovascular disease will not respond as strongly to ED drugs. "There are some men in whom none of these drugs work," Dr. Liou says.

How quickly do they work?

How soon the drugs start working ranges from 15 to 60 minutes. Neither Viagra nor Levitra will work at all if you take them after a meal, which blocks their absorption. However, neither Cialis nor Stendra interact with food this way. The onset time determines how soon you can engage in intercourse. Stendra and daily-use Cialis are closest to being an "on demand" erectile drug; using the others requires more planning.

How to use them properly

Dr. Liou says that some men come to him after getting a prescription from their primary care doctors, claiming that the drug doesn't work. Sometimes it's because they used it incorrectly. "The biggest misconception is that these drugs are an on/off switch for erections," Dr. Liou says. But the drugs don't work well without sexual stimulation. "During that time, you need to be with your partner and have foreplay," Dr. Liou says. "Don't take it, do the taxes or the dishes, and then meet at the bedroom thinking you'll be ready to go. It's not like that."

How long do they last?

The ED drugs break down at different rates in the body. The durations of action range from four hours to more than a day (for Cialis in the higher doses). Each dose should be sufficient to provide a full cycle of intercourse, from erection to climax.

"Will it last through another cycle? It's not guaranteed," Dr. Liou says. To have sex more than once a day, Cialis is your best bet.

How do the side effects differ?

The most common side effects of ED drugs, in order of most to least common are headache, flushing, upset stomach, nasal congestion, urinary tract infections, vision problems, diarrhea, dizziness, and rash. A man who has an erection that lasts four hours or more needs to get to a hospital or risk permanent damage.

Here are some issues particular to certain drugs:

  • Cialis is associated with backaches and muscle aches.

  • Blue-tinged vision is associated with Levitra and Viagra.

  • Lab tests suggest Stendra is less likely to cause side effects than the other drugs.

None of the ED drugs is safe to take with cardiac drugs called nitrates because it could cause a dangerous drop in blood pressure. Drugs that many men take for urinary symptoms, called alpha blockers, can also lower blood pressure, so take them at least four hours apart from ED drugs. Your doctor may start you on a smaller dose of the ED drug if you already take an alpha blocker, or may recommend the alpha blocker tamsulosin (Flomax), which affects blood pressure less.

The heart health connection

ED is often an early warning sign of underlying cardiovascular disease, such as clogged arteries (atherosclerosis). "It can predate a diagnosis of cardiovascular disease by at least a few years," Dr. Liou says. We don't have strong proof yet that starting to live a healthier lifestyle can reverse erectile problems, but it can't hurt.

ED drugs: How soon they start working and how long they last

Medication

Onset

Duration

avanafil (Stendra)

15-30 minutes

6-12 hours

sildenafil (Viagra)

30-60 minutes

4-5 hours

tadalafil (Cialis)

30-45 minutes

24-36 hours

tadalafil (Cialis) daily

continuous

continuous

vardenafil (Levitra)

30-60 minutes

4-5 hours