Choosing erectile dysfunction drugs
Here's how the different medications work.
- Reviewed by Howard E. LeWine, MD, Chief Medical Editor, 天博体育 Publishing; Editorial Advisory Board Member, 天博体育 Publishing
Since the 1990s, erectile dysfunction (ED) drugs have helped millions of men continue to enjoy an active sex life.
"While not much has changed in how they work or the types of drugs available, there still are things men should consider when choosing which one to try," says Dr. Michael O'Leary, a urologist and former director of men's health at Harvard-affiliated Brigham and Women's Hospital's Department of Urology.
The big four
There are four main FDA-approved ED drugs: sildenafil (Viagra), tadalafil (Cialis), vardenafil, and avanafil (Stendra).
All of these come as pills; vardenafil also is made in a dissolvable version you place under your tongue. Chewable ED drugs are available that contain the same active ingredients of sildenafil, tadalafil, and vardenafil. However, they are made to order in compounding pharmacies and may include other ingredients. Dr. O'Leary advises against using these custom-made products since they are not regulated or approved by the FDA.
The four ED drugs — known medically as PDE5 inhibitors — work similarly to increase blood flow into the penis, which helps men reach and maintain an erection. They do this by inhibiting phosphodiesterase type 5 (PDE5), an enzyme in blood vessel walls that controls blood flow. When a man is aroused, his body releases molecules that relax the smooth muscles in the blood vessels, allowing more blood to flow in. ED drugs prevent PDE5 from breaking down these substances, thus keeping the blood flowing.
ED drugs are effective in about 70% of men, according to Dr. O'Leary, but the results can vary. "A man with nerves or arteries damaged by prostate surgery, diabetes, or cardiovascular disease will not respond as strongly to ED drugs," he says. Also, while ED drugs can help men achieve and maintain an erection, they don't help with other sexual issues, such as low libido, premature ejaculation, or the inability to reach orgasm.
Choosing your ED drug
The main differences between ED drugs are how quickly they act and how long the effect lasts. Here's a breakdown:
- Avanafil takes about 15 to 30 minutes to work and lasts six to 12 hours.
- Sildenafil and vardenafil take effect in 30 minutes to an hour and last four to five hours.
- Tadalafil kicks in after 30 to 45 minutes and can last 24 to 36 hours.
Which drug is right for you? "Many doctors first prescribe sildenafil because it has been around the longest and has a high success rate," says Dr. O'Leary.
Men who want a longer-lasting effect might opt for tadalafil. Tadalafil is also available as a low-dose daily drug, so you have a constant amount of the drug in your bloodstream, which helps with spontaneous sex. (This version is also used to treat benign prostatic hyperplasia, or an enlarged prostate.)
The maximum dosages for ED drugs vary from 20 milligrams (mg) for tadalafil and vardenafil to 100 mg for sildenafil and 200 mg for avanafil. Your doctor usually begins with a low dose and increases it as needed.
"Once you reach the maximum dose, and the drug still doesn't work, taking more won't help," says Dr. O'Leary. "Also, switching to another ED drug usually won't make a difference."
Finding the right pricePrescription ED drugs can be expensive, and they're not always covered by medical insurance. Fortunately, generic versions are widely available for sildenafil, vardenafil, and tadalafil, at half the cost of the name-brand product or even less. (Generic avanafil is not yet available in the United States.) To find the least expensive ED drugs, shop around, as prices can vary from one pharmacy to another. The website compares prices from reputable pharmacies. |
Possible side effects
The most common side effects of ED drugs are headaches, upset stomach, nasal congestion, muscle pain, and facial flushing. But most of these are relatively mild and disappear after a few hours.
"ED drugs can make blood pressure temporarily drop, so don't use them if you take nitrates for angina (chest pain) or other heart problems," says Dr. O'Leary. However, there's no problem with nitrates found in food — for example, leafy green vegetables (spinach, kale) and root vegetables (beets, carrots).
You also need to be careful if you take alpha blockers such as tamsulosin (Flomax) and alfuzosin (Uroxatral), used to treat an enlarged prostate. "Make sure to take these medications at least four hours apart from an ED drug," says Dr. O'Leary.
It's also best not to take sildenafil or vardenafil soon after eating, as food can block their absorption. (Tadalafil and avanafil don't interact with food in this manner.)
Image: © Goodboy Picture Company/Getty Images
About the Author
Matthew Solan, Executive Editor, Harvard Men's Health Watch
About the Reviewer
Howard E. LeWine, MD, Chief Medical Editor, 天博体育 Publishing; Editorial Advisory Board Member, 天博体育 Publishing
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