What's the safest drug for ED? What the science tells us

Mike Bohl, MD, MPH, ALM - Contributor Avatar

Written by Michael Martin 

Mike Bohl, MD, MPH, ALM - Contributor Avatar

Written by Michael Martin 

last updated: Jul 27, 2020

3 min read

There are a number of prescription medications available for the treatment of erectile dysfunction (ED). Overall, they are relatively safe and very effective at restoring sexual function. These drugs include sildenafil (brand name Viagra), tadalafil (brand name Cialis), avanafil (brand name Stendra), and vardenafil (brand names Levitra and Staxyn). Known as PDE5 inhibitors, they all work in a similar way and have similar side effects (Schwartz, 2010).

PDE5 inhibitors work by blocking a natural enzyme known as PDE5, which serves as an erection's “off” switch. PDE5 tells blood vessels to constrict, causing blood to drain out of the penis, returning it to its flaccid state. When PDE5 is blocked by these drugs, it allows for a harder, more prolonged erection.

Some common side effects of PDE5 inhibitors include flushing, congestion, vision changes, muscle aches, and upset stomach. That said, they are generally well tolerated. If you are taking nitrates (such as nitroglycerin, isosorbide, nitroprusside, or amyl nitrite), you cannot take PDE5 inhibitors as the combination can be life-threatening (Schwartz, 2010). You should always consult with your healthcare provider before trying a new medication and purchase your medication from a reputable pharmacy.

Side effects or reactions to these medications can depend on the dosage. If you experience side effects while taking ED medication, talk with your healthcare provider. They may be able to adjust your dosage or choose a different ED medication that is right for you. 

Viagra Important Safety Information: Read more about serious warnings and safety info.

Cialis Important Safety Information: Read more about serious warnings and safety info.

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What causes ED?

ED is when a person can't achieve or maintain an erection sufficient for satisfying sex. This can take the form of erections that happen less frequently or are less firm than you'd like. 

ED is the most common sexual dysfunction there is. Experts believe that more than 30 million American men have experienced it at some point (Nunes, 2012). Erectile dysfunction can happen at any age, but it becomes more common with age. By the time a man is in his 40s, he has about a 40% chance of having experienced ED. That percentage increases by about 10% for each successive decade of life (Ferrini, 2017).

That said, ED is not considered to be a natural part of aging. It can often be a sign of a more dangerous underlying medical issue, including: 

  • Heart disease: The most common cause of erectile dysfunction in men over 50 is atherosclerosis, or hardening of the arteries (Cleveland Clinic, n.d.). As arteries stiffen or narrow, blood flow is reduced throughout the body, including to the penis, thereby hindering erections (American Heart Association, n.d.). 

  • High blood pressure (hypertension): In this condition, blood pumps through blood vessels more forcefully than it should, potentially damaging and narrowing the vessel walls and restricting blood flow (American Heart Association, n.d.).

  • Diabetes: High blood sugar associated with diabetes also can damage the walls of blood vessels, impeding blood flow (American Diabetes Association, n.d.). 

  • Stroke: A stroke can result in neurological damage that can contribute to ED (Koehn, 2019).

  • Cancer: A variety of physical and psychological issues related to cancer symptoms, surgery, and treatment can contribute to ED (American Cancer Society, n.d.).

  • Anxiety and depression: Depression, anxiety, and other psychological issues such as relationship problems and performance anxiety can all contribute to ED (Rajkumar, 2015)

Treatments for ED include oral medications; non-oral medications that are injected into the penis, causing an erection (alprostadil, BiMix, TriMix), lifestyle changes (such as eating better, getting more exercise, quitting smoking, drinking less alcohol, and losing weight); surgery (used to resolve specific issues contributing to the development of ED such as Peyronie’s disease); devices such as cock rings and penis pumps; counseling to resolve anxiety, depression or other issues that might be contributing to ED.

Which ED medication is best for me?

Deciding what ED medication is best for you depends on a number of factors, including:

  • Price/insurance coverage

  • Interactions with other medications you're taking

  • Dosages

  • How long it lasts

Talk with a healthcare provider about what ED medication might be best for you.


If you have any medical questions or concerns, please talk to your healthcare provider. The articles on Health Guide are underpinned by peer-reviewed research and information drawn from medical societies and governmental agencies. However, they are not a substitute for professional medical advice, diagnosis, or treatment.

How we reviewed this article

Every article on Health Guide goes through rigorous fact-checking by our team of medical reviewers. Our reviewers are trained medical professionals who ensure each article contains the most up-to-date information, and that medical details have been correctly interpreted by the writer.

Current version

July 27, 2020

Written by

Michael Martin

Fact checked by

Mike Bohl, MD, MPH, ALM

About the medical reviewer

Dr. Mike is a licensed physician and a former Director, Medical Content & Education at Ro.

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