Erectile dysfunction: Viagra and other oral medications

Wondering about drugs to treat erectile dysfunction? Find out how Viagra, Levitra and Cialis compare with each other.

Viagra, Levitra and Cialis are often the first treatment tried for erectile dysfunction — the inability to achieve or sustain an adequate erection for sexual activity. For most men with erectile problems, they work well and have few side effects. All three medications improve erectile function in the same basic way, but the effects of tadalafil (Cialis) last longer. This and a few other minor differences among these medications may make one a better choice over another for some men.

Viagra, Levitra and Cialis: How they work

Viagra, Levitra and Cialis increase levels of nitric oxide, a chemical produced by your body during sexual stimulation that causes blood vessels in the penis to relax and open. This allows you to achieve and maintain an erection. These medications don't automatically trigger an erection; sexual arousal is needed to start the whole process.

Which is best for you?

Viagra, Levitra and Cialis each have a slightly different chemical make up. These minor differences affect the way they work, such as how quickly they take effect and wear off; how they interact with other medications; and side effects. Your doctor will consider these factors when deciding if one of these medications is a good choice for you. Your doctor will also consider any other health problems you have and whether any of your current medications could cause problems when taken with Viagra, Levitra or Cialis.

	Viagra (sildenafil)	Levitra (vardenafil)	Cialis (tadalafil)
How to take	Without food, no more than once a day	Without food, no more than once a day	With or without food, no more than once a day
When to take	30 to 60 minutes before sex	30 to 60 minutes before sex	30 minutes before sex
Time an erection is possible	Up to four hours	Up to four hours	Up to 36 hours

Not safe for everyone

Although these erectile dysfunction medications can help many people, not all men can safely take them. Viagra, Levitra and Cialis may not be a good choice if you have:

• Heart problems, including a recent heart attack, heart pain (angina) during sex, heart failure, heart rhythm problems (arrhythmias)
• High or low blood pressure (hypertension or hypotension) that isn't controlled
• A history of stroke within the last six months
• Relatives with retina disorders, including retinitis pigmentosa
• Sickle cell anemia, leukemia or other health conditions that can cause an erection that won't subside (priapism)

Interactions with other medications

Tell your doctor about all medications you take, including herbal remedies. A number of other drugs, including certain antibiotics, anti-seizure medications, blood thinners and anti-arrhythmic heart medications can affect how well Viagra, Levitra or Cialis work and cause other side effects.

A few medications should never be taken with Viagra, Levitra or Cialis, or should be used with caution:

Never take Viagra, Levitra or Cialis if you take nitrate drugs to treat chest pain due to heart problems (angina). Like Viagra, Levitra and Cialis, nitrates dilate blood vessels. Their combined effects can cause dangerous low blood pressure and loss of consciousness. Medications that contain nitrates include:

• Nitroglycerin (Nitro-Bid, Minitran, others)
• Isosorbide dinitrate (Dilatrate-SR, Isordil, others)
• Isosorbide mononitrate (Imdur, Monoket, others)
• Recreational drugs such as amyl nitrite or nitrite ("poppers")

Talk to your doctor if you take alpha blockers, medications often used to treat an enlarged prostate. Alpha blockers can cause dangerously low blood pressure when combined with drugs for erectile dysfunction. Examples of alpha blockers include: tamsulosin (Flomax), terazosin (Hytrin) and doxazosin (Cardura).

• Don't use Viagra, Levitra or Cialis within four hours of taking an alpha blocker.
• If you do use an alpha blocker, never take sildenafil (Viagra) in doses above 25 milligrams.
• There's one exception to the rule about not taking alpha blockers with medications for erectile dysfunction: Tadalafil (Cialis) has been approved for use with the alpha blocker tamulosin (Flomax).

Erectile dysfunction medications for other health problems

Viagra, Levitra and Cialis all belong to a type of medications called phosphodiesterase-5 (PDE-5) inhibitors, which improve erectile function by affecting blood pressure. Experts are investigating whether these drugs may be useful to treat certain heart or blood flow problems. Revatio, the same medication as sildenafil (Viagra) was recently approved by the Food and Drug Administration as a treatment for pulmonary hypertension, a rare condition affecting blood flow to the lungs.

Common side effects

Viagra, Levitra and Cialis don't usually cause severe side effects. Some men have reported headache, flushing, indigestion, and a stuffy or runny nose after taking Viagra, Cialis or Levitra. Men taking Levitra have also reported back pain and muscle aches. In some men, Viagra caused temporary vision changes, such as "blue" vision.

Rare but serious side effects

In a small number of cases, men taking Viagra, Levitra or Cialis have reported:

• Vision loss. A few men using Viagra, Levitra and Cialis have had permanent vision loss due to a condition called nonarteritic anterior ischemic optic neuropathy (NAION). However, it's unclear whether the drug — or an underlying condition — caused blindness. If you have a retinal disorder, such as diabetic retinopathy, see your eye doctor before taking any medication for erectile dysfunction.
• Sudden hearing loss. Some men have reported hearing loss after taking Viagra, Levitra and Cialis. However, it isn't clear whether the hearing loss was directly caused by taking these medications. If you're taking one of these medications for erectile dysfunction and have sudden loss of hearing, don't take any more of the medication and seek medical help right away.
• An erection that doesn't subside on its own. Called priapism, this rare condition can be painful and requires medical treatment to avoid damage to your penis. If you have an erection that lasts more than four hours, see your doctor.

Erectile dysfunction: Don't ignore underlying cause

Taking Viagra, Levitra or Cialis without treating the original problem may improve sexual performance, but don't ignore an underlying issue by just taking pills to treat the symptom of another health issue. Getting proper treatment for the underlying cause of erectile dysfunction may help you prevent related health problems and improve sexual performance. A number of conditions can cause or worsen erectile dysfunction:

• Heart disease. In some cases, erectile dysfunction is the first sign of serious heart or blood vessel problems such as hardened arteries (atherosclerosis).
• Diabetes. Over time, uncontrolled diabetes can damage blood vessels and nerves, making it more difficult to get or keep an erection.
• Psychological issues. Depression or anxiety can cause sexual problems and often requires psychological counseling or medications to get better.
• Being overweight. Being overweight or obese can cause or worsen erectile dysfunction because of hormonal changes and related cardiovascular issues. Increased physical activity and losing weight can improve your overall health and sexual function.
• Low testosterone. Men who have low testosterone levels (hypogonadism) may need testosterone replacement therapy to increase sex drive and sexual performance.
• Lifestyle choices. Unhealthy habits such as drinking too much alcohol, smoking, using illegal drugs and a sedentary lifestyle can all worsen erectile dysfunction.

http://www.mayoclinic.com