Viagra (sildenafil) vs Levitra (vardenafil): differences and similarities

If you have erectile dysfunction (ED) and your healthcare provider has recommended an ED medication, you’re probably wondering what the differences are between the options on the market. In this article, we’ll look specifically at Viagra and Levitra, two commonly prescribed drugs. 

Viagra (generic name sildenafil) and Levitra (generic name vardenafil) are phosphodiesterase-5 enzyme (PDE5) inhibitors used to treat erectile dysfunction (ED). ED is a common sexual dysfunction that affects 30–50 million American men. People with ED may have trouble getting an erection, keeping an erection, or notice a lack of morning erections. Erection difficulties can prevent you from having a satisfying sex life (Sooriyamoorthy, 2021).  

PDE5 inhibitors are commonly used ED medications. These drugs work to improve erections by enhancing blood flow to the penis. Other PDE5 inhibitors include tadalafil (brand name Cialis) and avanafil (brand name Stendra). 

All of these drugs require arousal and sexual stimulation to work effectively. 

What is Viagra?

Viagra is FDA-approved to treat erectile dysfunction and pulmonary arterial hypertension (under the brand name Revatio). Some healthcare providers may use it "off-label" to treat Reynaud phenomenon, female sexual arousal disorder, and as an additional treatment for altitude-induced hypoxemia (altitude sickness) (Smith, 2021).

What is Levitra?

Levitra is an FDA-approved treatment of erectile dysfunction. Off-label uses include Reynaud phenomenon and pulmonary arterial hypertension (UpToDate, n.d.).

Both Viagra and Levitra are effective erectile dysfunction drugs. Clinical studies of each drug showed that around 75% of people taking the standard dose had improvements in their erections (DailyMed, 2020; DailyMed, 2021). There are no known differences in effectiveness between Viagra and Levitra.

Viagra and Levitra take approximately the same amount of time to work. 

Viagra

Viagra can be effective in as little as 30 minutes but can take up to two hours. Most people find that it starts working around 60 minutes after taking it. For this reason, you should take it about 60 minutes before sexual activity. You can take Viagra with food or on an empty stomach. However, if you take it with a high-fat meal, it may take longer to start working (DailyMed, 2020; Zucchi, 2019).

Levitra

For most people, Levitra starts working in about one hour, although it can start working as rapidly as 30 minutes after taking it. Like Viagra, you can take it with or without food, but it may take longer to be effective if you eat a high-fat meal (DailyMed, 2021; Zucchi, 2019). 

Viagra and Levitra last a similar amount of time in your body. 

Viagra

Most people find that Viagra's effects last for about four hours. However, this may depend on other factors like drug dose, other medications or supplements you're taking, and your overall health and psychological state (DailyMed, 2020).

Levitra

Levitra's effects last about 4–5 hours, about the same as Viagra. Like Viagra, how long it lasts may depend on other factors like your dose and overall health (DailyMed, 2021).

The dosage for these two drugs is the one area where there are some clear differences. 

Viagra

Sildenafil citrate (a.k.a. Viagra) comes in 25 mg, 50 mg, or 100 mg oral tablets. 

Most people start with the 50 mg dose, taken 30–60 minutes before sexual activity. However, your healthcare provider may recommend a higher or lower dose, depending on your medical history.

You can take Viagra with or without food. However, eating a high-fat meal may make the drug take longer to work (Zucchi, 2019).

The maximum daily dose for Viagra is 100 mg per day.

Levitra

Vardenafil hydrochloride (Levitra) is available as an oral tablet in varying strengths: 2.5 mg, 5 mg, 10 mg, and 20 mg. 

The recommended starting dose of Levitra for most people is 10 mg. However, your healthcare provider may recommend a higher or lower dose, depending on your medical history.

You should take it around 60 minutes before sexual activity. You can take Levitra with or without food, but a high-fat meal may delay its effects (Zucchi, 2019). 

The maximum daily dose for Levitra is 20 mg per day. 

Sildenafil (Generic Viagra)

Same active ingredient as the “Little Blue Pill” for up to 95% less

Get started

The side effects of Viagra and Levitra are very similar and may depend on your medication dosage, medical issues, and other factors. 

Priapism

Priapism is a prolonged erection that lasts more than four hours. This condition is a medical emergency because if the erection is not relieved, it can lead to permanent penis damage. All PDE5 inhibitors, including Viagra and Levitra, increase your risk of developing priapism and may be responsible for up to 25% of cases (Silberman, 2021).

Low blood pressure

PDE5 inhibitors work by encouraging the penis blood vessels to relax, allowing more blood to flow into the penis to maintain the erection. However, they don't just act on penis blood flow—they affect your blood vessels everywhere. Allowing your vessels to relax (or dilate) causes your blood pressure to drop. 

Sometimes we want this effect from a drug. However, it may be an issue for people with low blood pressure or who are taking other medications to lower their blood pressure. If your blood pressure drops too low, the results can be fatal. 

Viagra side effects

The most common side effects of Viagra include (Smith, 2021):

• Headaches

• Facial flushing

• Indigestion/heartburn 

• Back pain

• Stuffy nose

• Nausea 

Approximately 3% of people in clinical studies noted a change in their vision after taking Viagra. This was temporary and usually involved seeing a blue tinge to their vision. This color vision change may be due to sildenafil's ability to bind to PDE6 in addition to PDE5. PDE6 works in the retina, the part of your eye responsible for processing light and color. Fortunately, this side effect is temporary (DailyMed, 2020).

Viagra may also increase your risk of developing non-arteritic ischemic optic neuropathy (NAION) in people who already have other risk factors for this condition. NAION can lead to changes in your vision that may or may not be permanent. You can ask your eye care professional whether you are at an increased risk for developing NAION (DailyMed, 2020). 

People with preexisting risk factors for heart disease (like high blood pressure, high cholesterol, diabetes, etc.) or a history of heart attacks or strokes may develop chest pain or even a new heart attack. Unfortunately, it is difficult to tell from the clinical trials whether any new heart issues resulted from the medication, sexual activity, other factors, or some combination. Regardless, if you have a history of a heart condition or risk factors for heart disease, get medical advice from your healthcare provider before starting Viagra (DailyMed, 2020). 

Levitra side effects

The most common side effects of Levitra are similar to Viagra and include (DailyMed, 2021):

• Headache

• Runny nose

• Flushing

• Heartburn (dyspepsia)

• Flu-like symptoms

• Nausea

• Dizziness/lightheadedness

• Back pain

Levitra can also cause changes in color vision and increases your risk for NAION. Fortunately, like Viagra, these changes are usually temporary. Clinical trials suggest adverse effects of vision changes may be lower with Levitra than Viagra. However, this may be because Viagra has been around longer, so more vision changes have been reported over time. Other studies suggest that the visual side effects may be similar for Viagra and Levitra (DailyMed, 2021; Roessler, 2019).

Some people who take Levitra may experience QT prolongation. This is a slowing of some of the heart's electrical pathways and can cause a change in your heart rhythm. People born with a history of QT prolongation or who may be taking medications that also affect the QT interval may experience further prolongation (DailyMed, 2021). 

Consult your healthcare provider before starting any erectile dysfunction medications, including Viagra or Levitra. Discuss your medical history, as well as any over-the-counter supplements or prescription medicines you are taking so you can best prevent any potential drug interactions. 

Since both Viagra and Levitra are PDE5 inhibitors, they have similar drug interaction warnings. 

One of the most serious drug interactions with PDE5 inhibitors is a severe drop in blood pressure. This can occur if you take Viagra or Levitra with nitrates. Nitrates are often used to treat chest pain (e.g., nitroglycerin) or other heart conditions. Amyl nitrites, also called "poppers," are another example of nitrates. Don't take nitrates with PDE5 inhibitors because they can cause your blood pressure to fall too low, with potentially fatal consequences (DailyMed, 2020; DailyMed, 2021). 

People taking alpha-blockers to lower their blood pressure or treat prostate issues, like benign prostatic hyperplasia (BPH), should be careful if also using Viagra or Levitra. Alpha-blockers lower your blood pressure, as do PDE5 inhibitors, so combining the two drug types can again lead to a dangerous situation where your blood pressure is too low (DailyMed, 2020; DailyMed, 2021). 

Taking Viagra or Levitra if you are also taking riociguat for pulmonary hypertension is another situation that can cause a drop in blood pressure. 

Certain medications may disrupt how your liver processes drugs by affecting the CYP3A4 enzyme system. Drugs that inhibit the CYP3A4 enzyme may change the concentration of Viagra or Levitra, increasing your risk of side effects. Examples include ketoconazole, ritonavir, indinavir, and erythromycin. Grapefruit juice may also act on this enzyme and affect sildenafil or vardenafil drug levels (DailyMed, 2020; DailyMed, 2021).

There may be other potential drug interactions with Viagra or Levitra. Seek medical advice from your pharmacist or healthcare professional if you have questions or concerns. 

---

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

December 21, 2021

Written by

Chimene Richa, MD

Fact checked by

Steve Silvestro, MD

---

About the medical reviewer

Steve Silvestro, MD, Ro

Dr. Steve Silvestro is a board-certified pediatrician and Associate Director, Clinical Content & Education at Ro.