Asking for a friend: Are there side effects to ED pills?

You’ve seen the ads, heard the jokes and stories (4-hour erections!), but what’s the truth about pills men can take to help with erectile dysfunction, or ED?

All four prescription drugs available as pills for ED rely upon the same biochemical mechanism, said Urologist Bijan W. Salari, MD. They differ in side effects, how much time before sexual activity they can be taken, whether or not they are affected by eating a meal, and how long their effects last. They are: Viagra (sildenafil), Levitra (vardenafil), Cialis (tadalafil), and the newest, Stendra (avanafil). All but Stendra are available in less-expensive generic forms.

How They Work

All ED drugs work by increasing blood flow to the penis for an erection after stimulation, according to Dr. Salari. “They don’t cause an immediate erection,” he said.

The first of these four drugs to be approved by the U.S. Food and Drug Administration was Viagra in 1998. According to the FDA, an erection occurs when sexual stimulation causes nitric oxide to be released in the corpus cavernosum of the penis. This, in turn, activates an enzyme that increases amounts of cGMP, a substance that causes smooth muscle to relax in the corpus cavernosum. These two columns of spongy tissue, along with the urethra, compose the bulk of the penis, according to the National Cancer Institute. As smooth muscle relaxes, the corpus cavernosum fills with blood, producing an erection. Viagra and the three other ED drugs enhance the natural effect of nitric oxide by boosting levels of cGMP via interference with a substance that breaks it down.

When and How to Take ED Pills

Stendra works the fastest, within 30 minutes, according to Dr. Salari.

“Viagra and Cialis take more than 30 minutes to an hour to have good results,” he said.

For men prescribed doses of 100 or 200 mg, Stendra may work even faster and can be taken as little as 15 minutes before sex, according to the National Institutes of Health. A 30-minute wait for the drug to work applies to men on 50 mg pills.

Levitra takes 30 minutes to two hours to reach maximum blood levels, according to the FDA. It should be swallowed an hour before sex and can be taken with or without food, according to the NIH.

Viagra can be taken as long as four hours before sexual activity, according to the NIH.

Cialis stays in the body for longer than 48 hours, according to the FDA, unlike the other three drugs, which dissipate more quickly. Also, eating a meal shortly before taking Viagra, Levitra and Stendra can reduce their effectiveness, Dr. Salari said.

“If there is interest in sexual activity in the evening, take it before dinner,” Dr. Salari said.

“Alcohol – same as food,” he said. “Best to take on an empty stomach before alcohol.”

Alcohol can also worsen potential side effects of flushing and headaches, he said.

Side Effects

All four drugs share similar possible side effects, but Stendra has the least, Dr. Salari said. The oldest drug in this class, Viagra, may cause vision changes, such as having objects appear bluish.

Possible side effects of all four drugs include flushing, headache, heartburn and stomach upset, according to the National Institutes of Health. In addition:

• Viagra may cause diarrhea, nosebleeds, muscle aches and pain or tingling in the limbs.
• Levitra may cause a runny nose and flu-like symptoms.
• Cialis may cause a cough, nausea, diarrhea and body pains.
• Stendra may cause back pain.

Other, more serious side effects of these pills are possible, and should be reported to your doctor, according to the NIH. These include chest pain, loss of sight or hearing, fainting, hives or rash, difficulty swallowing or breathing, irritation during urination and swelling of face, feet or hands. Most notorious of these may be an erection lasting longer than four hours, a condition called priapism.

While this potential side effect may seem an attractive option to some guys, such erections can be painful and cause tissue damage, according to the International Society for Sexual Medicine.

However, the danger of priapism to men taking ED drugs may be blown out of proportion, according to a July 2020 article in The Journal of Sexual Medicine, which found only 2.9 percent of reported cases of drug-induced priapism involved ED drugs.

“It’s very, very uncommon,” Dr. Salari said. “It’s extremely unlikely. It’s usually from an overdose.”

He urged patients to take the prescribed amount, not more. The NIH states these drugs are not to be taken more than once every 24 hours. The FDA has also issued several warnings about both nonprescription pills touted as cures for ED and sexual enhancement products for men and women. These may contain harmful ingredients or prescription drugs that aren’t listed on their labels.

ED and Your Health

Difficulty having or maintaining an erection is a common problem among men as they age, Dr. Salari said. It can result from underlying health problems.

“Men that have any history of heart disease, diabetes or high cholesterol are more likely to have ED,” he said.

“The healthier the heart is, the healthier the penis is.”

Men should talk with their doctors about any medications they take and their general health when seeking treatment for ED. Men on the blood thinner warfarin (Coumadin) will need their blood levels checked more often if they take one of these drugs, Dr. Salari said. Those taking nitroglycerin for chest pain should seek their cardiologist’s approval before taking ED medicine, he added.

“When I see a patient (for ED), the first question I ask myself is why? What’s the underlying problem? It can be a manifestation of having heart disease or diabetes, but it also can be a sign of low testosterone.”

Men’s testosterone levels drop as they age, and Dr. Salari recommends men with ED have the levels of this male hormone checked.

ED drugs can’t stop the march of time or cure underlying health problems, but they can help the quality of life for many men, he said.

“Most patients are happy,” Dr. Salari said. “It can be with progression of ED that other treatments (such as penile injections) are needed years later. It can be very beneficial to patients for several years.”