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Health Guide / Erectile dysfunction medications

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

Mike Bohl, MD, MPH, ALM

Reviewed by Mike Bohl, MD, MPH, ALM, written by Michael Martin

Last updated: Jul 27, 2020
4 min read

table of contents

  1. What causes ED?
  2. Which ED medication is best for me?

Disclaimer

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.

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; see Important Safety Information), tadalafil (brand name Cialis; see Important Safety Information), 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. 

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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.

References

  1. American Cancer Society. How Cancer Can Affect Erections. (n.d.). Retrieved Aug. 23, 2020, from https://www.cancer.org/treatment/treatments-and-side-effects/physical-side-effects/fertility-and-sexual-side-effects/sexuality-for-men-with-cancer/erections-and-treatment.html
  2. American Diabetes Association. Erectile Dysfunction. (n.d.). Retrieved Aug. 23, 2020, from https://www.diabetes.org/resources/men/erectile-dysfunction
  3. American Heart Association. How High Blood Pressure Can Affect Your Sex Life. (n.d.). Retrieved Aug. 23, 2020, from https://www.heart.org/en/health-topics/high-blood-pressure/health-threats-from-high-blood-pressure/how-high-blood-pressure-can-affect-your-sex-life
  4. Erectile Dysfunction & Heart Disease. (n.d.). Retrieved from https://my.clevelandclinic.org/health/diseases/15029-heart-disease–erectile-dysfunction
  5. Ferrini, M. G., Gonzalez-Cadavid, N. F., & Rajfer, J. (2017). Aging related erectile dysfunction-potential mechanism to halt or delay its onset. Translational Andrology and Urology, 6(1), 20–27. https://doi.org/10.21037/tau.2016.11.18. Retrieved from https://tau.amegroups.com/article/view/13319/13808 
  6. Koehn, J., Crodel, C., Deutsch, M., Kolominsky-Rabas, P. L., Hösl, K. M., Köhrmann, M., Schwab, S., & Hilz, M. J. (2015). Erectile dysfunction (ED) after ischemic stroke: association between prevalence and site of lesion. Clinical Autonomic Research : Official Journal of the Clinical Autonomic Research Society, 25(6), 357–365. https://doi.org/10.1007/s10286-015-0313-y. Retrieved from https://link.springer.com/article/10.1007%2Fs10286-015-0313-y 
  7. Nunes, K. P., Labazi, H., & Webb, R. C. (2012). New insights into hypertension-associated erectile dysfunction. Current Opinion in Nephrology and Hypertension, 21(2), 163–170. doi: 10.1097/mnh.0b013e32835021bd. Retrieved from https://pubmed.ncbi.nlm.nih.gov/22240443/
  8. Rajkumar, R. P., & Kumaran, A. K. (2015). Depression and anxiety in men with sexual dysfunction: a retrospective study. Comprehensive Psychiatry, 60, 114–118. https://doi.org/10.1016/j.comppsych.2015.03.001. Retrieved from https://www.sciencedirect.com/science/article/abs/pii/S0010440X15000346?via%3Dihub 
  9. Schwartz, B. G., & Kloner, R. A. (2010). Drug Interactions With Phosphodiesterase-5 Inhibitors Used for the Treatment of Erectile Dysfunction or Pulmonary Hypertension. Circulation, 122, 88-95. Retrieved from https://www.ahajournals.org/doi/10.1161/CIRCULATIONAHA.110.944603
Mike Bohl, MD, MPH, ALM
Mike Bohl, MD, MPH, ALM

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

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Related articles

Important Safety Information for Sildenafil (Viagra)

What are the most important things I need to know about VIAGRA® (sildenafil citrate) 25 mg, 50 mg, and 100 mg tablets and generic VIAGRA®?

Discuss your health with your doctor to ensure that you are healthy enough for sex. If you experience chest pain, dizziness, or nausea during sex, seek immediate emergency medical attention.

  • VIAGRA® and generic VIAGRA® can cause serious side effects. Serious, but rare, side effects include:
    • an erection that will not go away (priapism). If you have an erection that lasts more than 4 hours, seek emergency medical attention right away. If it is not treated right away, priapism can permanently damage your penis.
    • sudden vision loss in one or both eyes. Sudden vision loss in one or both eyes can be a sign of a serious eye problem called non-arteritic anterior ischemic optic neuropathy (NAION). Stop taking VIAGRA and call your healthcare provider right away if you have any sudden vision loss
    • sudden hearing decrease or hearing loss. Some people may also have ringing in their ears (tinnitus) or dizziness. If you have these symptoms, stop taking VIAGRA and contact a doctor right away
  • VIAGRA® does not protect against sexually transmitted diseases, including HIV.

Who should not take VIAGRA® or generic VIAGRA®? 

Do not take VIAGRA® or generic VIAGRA® if you:

  • Take any medicines called nitrates, often prescribed for chest pain, or guanylate cyclase stimulators like Adempas (riociguat) for pulmonary hypertension. Your blood pressure could drop to an unsafe level
  • Are allergic to sildenafil, as contained in VIAGRA® and REVATIO®, or any of the ingredients in VIAGRA® or generic VIAGRA® tablets.
  • Are a women or a child

When should I call my primary provider? 

Call your primary provider right away if you:

  • Have an erection that lasts longer than 4 hours
  • Experience a sudden loss of vision in one or both eyes
  • Experience a sudden decrease in or loss of hearing
  • Experience chest pain, dizziness, or nausea during sex
  • Take too much Viagra or sildenafil citrate 

If you are experiencing a medical emergency, call 911 or seek immediate medical attention.

What are the most common side effects of VIAGRA® and generic VIAGRA®?

The most common side effects are:

  • headache
  • flushing
  • upset stomach
  • abnormal vision, such as changes in color vision (such as having a blue color tinge) and blurred vision
  • stuffy or runny nose
  • back pain
  • muscle pain
  • nausea
  • dizziness
  • rash

What should I tell my Roman-affiliated provider before taking VIAGRA® and generic VIAGRA®?

Before you take VIAGRA® or generic VIAGRA® , tell your healthcare provider if you:

  • Have or have had heart problems such as a heart attack,irregular heartbeat, angina, chest pain, narrowing of the aortic valve, or heart failure
  • Have had heart surgery within the last 6 months
  • Have pulmonary hypertension
  • Have had a stroke
  • Have low blood pressure, or high blood pressure that is not controlled
  • Have a deformed penis shape
  • Have had an erection that lasted for more than 4 hours
  • Have problems with your blood cells such as sickle cell anemia, multiple myeloma, or leukemia
  • Have retinitis pigmentosa, a rare genetic (runs in families) eye disease
  • Have ever had severe vision loss, including an eye problem called NAION
  • Have bleeding problems
  • Have or have had stomach or intestinal ulcers
  • Have liver problems
  • Have kidney problems or are having kidney dialysis
  • Have any other medical conditions 

Tell your healthcare provider about all the medicines you take, including prescription and over-the-counter medicines, vitamins, and herbal supplements.

VIAGRA may affect the way other medicines work, and other medicines may affect the way VIAGRA works, causing side effects.

Especially tell your healthcare provider if you take any of the following:

  • Medicines called nitrates
  • Medicines called guanylate cyclase stimulators such as Adempas® (riociguat)
  • Medicines called alpha-blockers such as Hytrin® (terazosin HCl), Flomax® (tamsulosin HCl), Cardura® (doxazosin mesylate), Minipress® (prazosin HCl), Uroxatral® (alfuzosin HCl), Jalyn® (dutasteride and tamsulosin HCl), or Rapaflo® (silodosin). Alpha-blockers are sometimes prescribed for prostate problems or high blood pressure. In some patients, the use of VIAGRA® with alpha-blockers can lead to a drop in blood pressure or to fainting
  • Medicines called HIV protease inhibitors, such as ritonavir (Norvir®), indinavir sulfate (Crixivan®), saquinavir (Fortovase® or Invirase®), or atazanavir sulfate (Reyataz®)
  • Oral antifungal medicines, such as ketoconazole (Nizoral®) and itraconazole (Sporanox®)
  • Antibiotics, such as clarithromycin (Biaxin®), telithromycin (Ketek®), or erythromycin
  • Other medicines that treat high blood pressure
  • Other medicines or treatments for ED
  • VIAGRA® contains sildenafil, which is the same medicine found in another drug called REVATIO®. REVATIO® is used to treat a rare disease called pulmonary arterial hypertension (PAH). VIAGRA® should not be used with REVATIO® or with other PAH treatments containing sildenafil or any other PDE5 inhibitors (such as Adcirca [tadalafil])

Withholding or providing inaccurate information about your health and medical history in order to obtain treatment may result in harm, including, in some cases, death.

What is the FDA-approved use of VIAGRA® and generic VIAGRA®?

VIAGRA® (sildenafil citrate) is prescription medicine used to treat erectile dysfunction (ED). 

Roman-affiliated doctors may prescribe VIAGRA® or generic VIAGRA® for the treatment of premature ejaculation (PE), if they believe in their medical judgment that it is an appropriate course of treatment. While this is not an FDA-approved use of the drug, the American Urological Association has included the use of sildenafil citrate in the treatment of PE in its Guideline on the Pharmacologic Management of Premature Ejaculation.  

You are encouraged to report negative side effects of prescription products to the FDA. Visit www.fda.gov/medwatch or call 1-800-FDA-1088.

Please see the full Prescribing Information for complete safety information. 

Product names referenced herein are trademarks of their respective owners.

Important Safety Information for Tadalafil (Cialis)

What Is The Most Important Information I Should Know About CIALIS® (tadalafil) and generic CIALIS®? 

  • CIALIS® and generic CIALIS® can cause serious side effects. Serious, but rare, side effects include:
    • An erection that won’t go away (priapism). If you get an erection that lasts more than 4 hours, get medical help right away. Priapism must be treated as soon as possible or lasting damage can happen to your penis, including the inability to have erections. 
    • Changes in vision. Color vision changes, such as seeing a blue tinge (shade) to objects or having difficulty telling the difference between the colors blue and green. 
    • Sudden decrease or loss of vision. In rare instances, men taking PDE5 inhibitors (oral erectile dysfunction medicines, including CIALIS® and generic CIALIS®) reported a sudden decrease or loss of vision in one or both eyes. It is uncertain whether PDE5 inhibitors directly cause the vision loss. If you experience sudden decrease or loss of vision, stop taking PDE5 inhibitors, including CIALIS® and generic CIALIS®, and call a healthcare provider right away. 
    • Sudden loss or decrease in hearing. Sudden loss or decrease in hearing, sometimes with ringing in the ears and dizziness, has been rarely reported in people taking PDE5 inhibitors, including CIALIS® and generic CIALIS®. It is not possible to determine whether these events are related directly to the PDE5 inhibitors, to other diseases or medications, to other factors, or to a combination of factors. If you experience these symptoms, stop taking CIALIS® and generic CIALIS® and contact a healthcare provider right away. 
  • CIALIS® and generic CIALIS® can cause your blood pressure to drop suddenly to an unsafe level if it is taken with certain other medicines. You could get dizzy, faint, or have a heart attack or stroke. 
  • Never take CIALIS® or generic CIALIS® with any nitrate or guanylate cyclase stimulator medicines. Do not take CIALIS® or generic CIALIS® if you take any medicines called “nitrates.” Nitrates are commonly used to treat angina. Angina is a symptom of heart disease and can cause pain in your chest, jaw, or down your arm. Medicines called nitrates include nitroglycerin that is found in tablets, sprays, ointments, pastes, or patches. Nitrates can also be found in other medicines such as isosorbide dinitrate or isosorbide mononitrate. 
  • Some recreational drugs called “poppers” also contain nitrates, such as amyl nitrite and butyl nitrite. 
  • Do not take CIALIS® or generic CIALIS® if you take medicines called guanylate cyclase stimulators which include: Riociguat (Adempas®) a medicine that treats pulmonary arterial hypertension and chronic thromboembolic pulmonary hypertension (pulmonary hypertension due to chronic blood clots in the lungs). Ask your healthcare provider or pharmacist if you are not sure if any of your medicines are nitrates or guanylate cyclase stimulators, such as riociguat. 
  • Tell all of your healthcare providers that you take CIALIS® or generic CIALIS®. If you need emergency medical care for a heart problem, it will be important for your healthcare provider to know when you last took CIALIS® or generic CIALIS®. After taking a single tablet, some of the active ingredient of CIALIS® or generic CIALIS® remains in your body for more than 2 days. The active ingredient can remain longer if you have problems with your kidneys or liver, or you are taking certain other medications. 
  • Stop sexual activity and get medical help right away if you get symptoms such as chest pain, dizziness, or nausea during sex. Sexual activity can put an extra strain on your heart, especially if your heart is already weak from a heart attack or heart disease. 
  • CIALIS® and generic CIALIS® for the Treatment of erectile dysfunction (ED): 
    • ED is a condition where the penis does not fill with enough blood to harden and expand when a man is sexually excited, or when he cannot keep an erection. A man who has trouble getting or keeping an erection should see his healthcare provider for help if the condition bothers him.
    • CIALIS® and generic CIALIS® help increase blood flow to the penis and may help men with ED get and keep an erection satisfactory for sexual activity. Once a man has completed sexual activity, blood flow to his penis decreases, and his erection goes away. Some form of sexual stimulation is needed for an erection to happen with CIALIS® or generic CIALIS®. 
    • CIALIS® and generic CIALIS® do not: 
      • Cure ED 
      • Increase a man’s sexual desire 
      • Protect a man or his partner from sexually transmitted diseases, including HIV. Speak to your healthcare provider about ways to guard against sexually transmitted diseases. 
      • Serve as a male form of birth control 
    • Do not use CIALIS® or generic CIALIS® with other ED medications.
  • CIALIS® and generic CIALIS® are only for men over the age of 18, including men with diabetes or who have undergone prostatectomy. 
  • CIALIS® and generic CIALIS® are not for women or children. 
  • CIALIS® and generic CIALIS® must be used only under a healthcare provider’s care. 
    • Take CIALIS® or generic CIALIS® exactly as your healthcare provider prescribes it. Your healthcare provider will prescribe the dose that is right for you. Do not change your dose or the way you take CIALIS® or generic CIALIS® without talking to your healthcare provider.

Who Should Not Take CIALIS® or generic CIALIS®? 

Do not take CIALIS® or generic CIALIS® if you:

  • Have severe liver disease. Tell your doctor if you have mild to moderate liver disease as you may need dosage reductions.
  • Have severe kidney disease. Tell your doctor if you have mild to moderate kidney disease as you may need dosage reductions
  • Take any medicines called “nitrates” 
  • Use recreational drugs called “poppers” like amyl nitrite and butyl nitrite 
  • Take any medicines called guanylate cyclase stimulators, such as riociguat 
  • Are allergic to CIALIS®, tadalafil or ADCIRCA®, or any of its ingredients

When should I call my primary provider?

Call your primary provider right away if you: 

  • Have an erection that lasts longer than 4 hours
  • Experience a sudden loss of vision in one or both of your eyes
  • Experience a sudden decrease or loss hearing
  • Take too much CIALIS® or generic CIALIS® 
  • Have an allergic reaction to CIALIS® or generic CIALIS®
  • Symptoms of an allergic reaction may include: 
  • Rash 
  • Hives 
  • Swelling of the lips, tongue, or throat 
  • Difficulty breathing or swallowing 

Call your healthcare provider or get help right away if you have any of the symptoms of an allergic reaction listed above. 

If you are experiencing a medical emergency, call 911 or seek immediate medical attention.

What Should I Tell My Roman-affiliated Provider Before Taking CIALIS® and generic CIALIS®? 

Tell your Roman-affiliated provider about all your medical problems, including if you:

  • Have heart problems such as angina, heart failure, irregular heartbeats, or have had a heart attack. Ask your healthcare provider if it is safe for you to have sexual activity. You should not take CIALIS® and generic CIALIS® if your healthcare provider has told you not to have sexual activity because of your health problems. 
  • Have pulmonary hypertension
  • Have low blood pressure or have high blood pressure that is not controlled 
  • Have had a stroke 
  • Have liver problems 
  • Have kidney problems or require dialysis 
  • Have retinitis pigmentosa, a rare genetic (runs in families) eye disease 
  • Have ever had severe vision loss, including a condition called NAION 
  • Have stomach or intestinal ulcers 
  • Have a bleeding problem 
  • Have a deformed penis shape or Peyronie’s disease 
  • Have had an erection that lasted more than 4 hours 
  • Have blood cell problems such as sickle cell anemia, multiple myeloma, or leukemia 

Tell your healthcare provider about all the medicines you take including prescription and non-prescription medicines, vitamins, and herbal supplements. 

Especially tell your healthcare provider if you take any of the following: 

  • Medicines called nitrates 
  • Medicines called guanylate cyclase stimulators, such as riociguat (Adempas®), used to treat pulmonary hypertension 
  • Medicines called alpha blockers. These include Hytrin® (terazosin HCl), Flomax® (tamsulosin HCl), Cardura® (doxazosin mesylate), Minipress® (prazosin HCl), Uroxatral® (alfuzosin HCl), 4 Jalyn® (dutasteride and tamsulosin HCl) or Rapaflo® (silodosin). Alpha-blockers are sometimes prescribed for prostate problems or high blood pressure. If CIALIS® or generic CIALIS® is taken with certain alpha blockers, your blood pressure could suddenly drop. You could get dizzy or faint.
  • Other medicines to treat high blood pressure (hypertension) 
  • Medicines called HIV protease inhibitors, such as ritonavir (Norvir® , Kaletra® )
  • Oral antifungals such as ketoconazole (Nizoral® ), itraconazole (Sporanox® ) 
  • Antibiotics such as clarithromycin (Biaxin® ), telithromycin (Ketek® ), erythromycin (several brand names exist. Please consult your healthcare provider to determine if you are taking this medicine). 
  • Other medicines or treatments for ED. 
  • Tadalafil is also marketed as ADCIRCA® for the treatment of pulmonary arterial hypertension. Do not take both CIALIS® or generic CIALIS® and ADCIRCA®. Do not take sildenafil citrate (Revatio®, Viagra®) with CIALIS® or generic CIALIS®. 

Withholding or providing inaccurate information about your health and medical history in order to obtain treatment may result in harm, including, in some cases, death.

What are the most common side effects of CIALIS® or generic CIALIS®?

The most common side effects with CIALIS® and generic CIALIS® are:

  • Headache
  • Indigestion
  • Back pain
  • Muscle aches
  • Flushing
  • Stuffy or runny nose

What is the FDA-approved Use of CIALIS® and generic CIALIS®? 

CIALIS® and generic CIALIS® are prescription medicines used to treat erectile dysfunction (ED), symptoms of benign  prostatic hyperplasia (BPH), or both.

Roman-affiliated doctors may prescribe CIALIS® for the treatment of premature ejaculation (PE), if they believe in their medical judgment that it is an appropriate course of treatment.  

You are encouraged to report negative side effects of prescription products to the FDA. Visit www.fda.gov/medwatch or call 1-800-FDA-1088.

Please see the full Prescribing Information for complete safety information.