Erectile dysfunction (ED) is more common than you may realize and affects approximately 30 million men in the U.S.1 For many ED patients, medications have proven to be quite effective in improving their sex lives.
Choosing the right medication depends on individual needs. Sildenafil, tadalafil, avanafil and vardenafil are all ED treatments with some similarities and a few key differences. This guide will examine all four medications to help you determine which one might be right for you.
Key Takeaways
Four prescription PDE5 inhibitors — sildenafil, tadalafil, avanafil and vardenafil— treat ED in similar ways but differ in how quickly they work, how long they last, side effects and cost.
Tadalafil offers the longest “window” (up to 36 hours); avanafil is the fastest (15 to 30 minutes), while sildenafil and vardenafil land in the middle for both onset and duration.
Generic versions for sildenafil (Viagra®), tadalafil (Cialis®) avanafil (Stendra®) and vardenafil (Levitra®) are generally less expensive than the brand names.
What ED Medications are Available?
The most common ED medications are a group of phosphodiesterase type 5 (PDE5) inhibitors.2 These medications help improve blood flow to the body’s tissues, including the genitals. The four most popular PDE5 inhibitors on the market are:
Sildenafil (Generic Viagra®)
Avanafil (Generic Stendra®)
Vardenafil (Generic Levitra®)
Many of the ED medications available work similarly within the body, but each has a few unique differences. It is important to talk to a licensed healthcare provider about your options before deciding which ED medication will work best for your needs.For informational purposes, we’ve provided a detailed comparison for every ED medication.
ED prescriptions starting at $1 per tablet.
Know your ED prescription costs upfront. Get secure, private treatment online from RedBox Rx with FDA-approved meds starting at $1 per pill.
Get Started for FreeSildenafil (Viagra) vs. Tadalafil (Cialis®)
The main difference between sildenafil and tadalafil is how long they last with tadalafil offering a much longer window of effectiveness than sildenafil.
Medication Class
Sildenafil and tadalafil are both phosphodiesterase type 5 (PDE5) inhibitors.
Dosage
Sildenafil is available in 20 mg, 25 mg, 50 mg or 100 mg dosages. It is also taken as needed but not more than once in 24 hours.3
There are two ways to take tadalafil — daily or as needed. A common daily dose is 2.5 mg to 5 mg. The as-needed dosage is 10 mg to 20 mg.4
Onset
The main difference between sildenafil and tadalafil is the amount of time it takes for the medications to begin working and how long they remain effective. Sildenafil takes an average of one hour to begin working, while tadalafil starts working in closer to 30 minutes.5
Duration
Tadalafil has the longest life of any PDE5 inhibitors. It can remain effective for 24 to 36 hours after ingestion. Sildenafil generally only remains effective for approximately four to six hours.6
Effectiveness
Both medications have been shown to be an effective treatment for ED.
Up to 87% of men in one study reported sildenafil improved their erections.7
In clinical studies of tadalafil, 82% of men with an average age of 59 reported improved erections after taking it for 12 weeks.8
Side Effects
Sildenafil and tadalafil have several common side effects, including headache, heartburn, diarrhea, nausea, flushing and muscle pain.
Side effects unique to sildenafil include nosebleeds; nasal congestion; changes in color vision or sensitivity to light; and numbness, burning or tingling in the arms, hands, feet or legs. A side effect unique to tadalafil is a cough.9,10
Cost
With RedBox Rx, sildenafil and tadalafil are both as low as $1 per tablet.
Sildenafil (Viagra®) vs. Avanafil (Stendra®)
What sets avanafil apart from sildenafil is the quicker action and lower risk of side effects.
Medication Class
Sildenafil and avanafil are both phosphodiesterase type 5 (PDE5) inhibitors.
Dosage
Sildenafil is available in 20 mg, 25 mg, 50 mg or 100 mg dosages. It is also taken as needed but not more than once in 24 hours.11
Avanafil is available in 50 mg, 100 mg and 200 mg dosages. It is taken as needed but not more than once in 24 hours.12
Onset
Avanafil takes an average of 15 to 30 minutes to take effect, while sildenafil takes an average of 30 to 60 minutes.13
Duration
Both medications are similar. Sildenafil lasts four to six hours, while avanafil lasts about five hours.14
Effectiveness
Both medications have been shown to be an effective treatment for ED.
Up to 87% of men in one study reported sildenafil improved their erections.15
Avanafil has seen success rates of 64% for the 50 mg dose, 74% for the 100 mg dose and 77% for the 200 mg dose.16
Side Effects
Both avanafil and sildenafil may cause headaches, flushing and back pain. In addition, sildenafil may also cause heartburn; diarrhea; nausea; nosebleeds; nasal congestion; pain in the muscles, arms or legs; sensitivity to light; changes in color vision (such as seeing a blue tinge on objects); and numbness, burning or tingling in the arms, hands, feet or legs.17,18
Cost
With RedBox Rx, sildenafil is as low as $1 per tablet and avanafil is $40 per tablet with a 20-tablet order.
Tadalafil (Cialis®) vs. Avanafil (Stendra®)
Choosing between tadalafil and avanafil for erectile dysfunction comes down to whether you hope to improve speed or endurance.
Medication Class
Tadalafil and avanafil are both phosphodiesterase type 5 (PDE5) inhibitors.
Dosage
There are two ways to take tadalafil — daily or as needed. A common daily dose is 2.5 mg to 5 mg. The as-needed dosage is 10 mg to 20 mg.19
Avanafil is available in 50 mg, 100 mg and 200 mg dosages. It is taken as needed but not more than once in 24 hours.20
Onset
Avanafil is one of the fastest-acting PDE5 inhibitors and takes approximately 15 to 30 minutes for effects to start. Tadalafil can take approximately 30 minutes to fully kick in.21
Duration
Tadalafil effects last considerably longer and stay active for up to 36 hours. Avanafil’s window of effectiveness is about five hours.22
Effectiveness
Both medications have been shown to be an effective treatment for ED.
In clinical studies of tadalafil, 82% of men with an average age of 59 reported improved erections after taking it for 12 weeks.23
Avanafil has seen success rates of 64% for the 50 mg dose, 74% for the 100 mg dose and 77% for the 200 mg dose.24
Side Effects
One advantage avanafil has compared to tadalafil is fewer side effects. Both may cause headaches, flushing and back pain. In addition, tadalafil may cause heartburn; nausea; diarrhea; cough; and pain in the stomach, muscles, arms or legs.25,26
Cost
With RedBox Rx, tadalafil is as low as $1 per tablet and avanafil is $40 per tablet with a 20-tablet order.
Vardenafil (Levitra®) vs. Sildenafil (Viagra)
Vardenafil and sildenafil are closely matched PDE5 inhibitors, with the main differences coming down to cost and a slightly longer window of effectiveness for vardenafil.
Medication Class
Vardenafil and sildenafil are both phosphodiesterase type 5 (PDE5) inhibitors.
Dosage
Vardenafil is available in 5 mg, 10 mg and 20 mg dosages. It is taken as needed but not more than once in 24 hours.27
Sildenafil is available in 20 mg, 25 mg, 50 mg or 100 mg dosages. It is also taken as needed but not more than once in 24.28
Onset
Both vardenafil and sildenafil take effect in 30 to 60 minutes.29
Duration
Both drugs are similar. Vardenafil lasts five to seven hours, while sildenafil lasts four to six hours.30
Effectiveness
Both medications have been shown to be an effective treatment for ED.
Vardenafil has seen success rates in 71% of men under the age of 45, 76% of men aged 45 to 64 and 85% of men over 65.31
Up to 87% of men in one study reported sildenafil improved their erections.32
Side Effects
Vardenafil and sildenafil both may cause headaches, heartburn, flushing, a stuffy or runny nose, and upset stomach. Sildenafil may cause additional side effects, including nosebleeds; numbness, burning or tingling in the arms, hands, feet or legs; pain in the muscles, back, arms or legs; sensitivity to light; or changes in color vision, such as seeing a blue tinge on objects.33,34
Cost
With RedBox Rx, generic vardenafil is as low as $3 per tablet and sildenafil is as low as $1 per tablet.
Vardenafil (Levitra®) vs. Tadalafil (Cialis®)
The biggest difference between vardenafil and tadalafil is duration, as tadalafil stays effective far longer than vardenafil.
Medication Class
Vardenafil and tadalafil are both phosphodiesterase type 5 (PDE5) inhibitors.
Dosage
Vardenafil is available in 5 mg, 10 mg and 20 mg dosages. It is also taken as needed but not more than once in 24 hours.35
There are two ways to take tadalafil — daily or as needed. A common daily dose is 2.5 mg to 5 mg. The as-needed dosage is 10 mg to 20 mg.36
Onset
Vardenafil takes effect in 30 to 60 minutes, and tadalafil takes effect in around 30 minutes.37
Duration
Tadalafil effects last considerably longer and stay active for up to 36 hours. Vardenafil’s window of effectiveness is five to seven hours.38
Effectiveness
Both medications have been shown to be an effective treatment for ED.
Vardenafil has seen success rates in 71% of men under the age of 45, 76% of men aged 45 to 64 and 85% of men over 65.39
In clinical studies of tadalafil, 82% of men with an average age of 59 reported improved erections after taking it for 12 weeks.40
Side Effects
Both medications may cause headache, heartburn and flushing. Other common side effects of vardenafil include upset stomach, stuffy or runny nose, and flu-like symptoms.41 Other common side effects of tadalafil include nausea, diarrhea, cough, and pain in the stomach, back, muscles, arms or legs.42
Cost
With RedBox Rx, generic vardenafil is as low as $3 per tablet and tadalafil is as low as $1 per tablet.
Vardenafil (Levitra®) vs. Avanafil (Stendra®)
Vardenafil and avanafil are both well suited to spontaneous use, with avanafil taking effect a bit faster and both lasting a similar amount of time.
Medication Class
Vardenafil and avanafil are both phosphodiesterase type 5 (PDE5) inhibitors.
Dosage
Vardenafil is available in 5 mg, 10 mg and 20 mg dosages. It is also taken as needed but not more than once in 24 hours.43
Avanafil is available in 50 mg, 100 mg and 200 mg dosages. It is taken as needed but not more than once in 24 hours.44
Onset
Vardenafil and avanafil are both good medications for spontaneous use. Avanafil kicks in a bit faster, with users feeling effects in 15 to 30 minutes on average. Vardenafil has an average time of impact of 30 to 60 minutes.45
Duration
Both medications are similar, as vardenafil lasts five to seven hours, while avanafil lasts about five hours.46
Effectiveness
Both medications have been shown to be an effective treatment for ED.
Vardenafil has seen success rates in 71% of men under the age of 45, 76% of men aged 45 to 64 and 85% of men over 65.47
Avanafil has seen success rates of 64% for the 50 mg dose, 74% for the 100 mg dose and 77% for the 200 mg dose.48
Side Effects
Both drugs may cause headaches; flushing; upset stomach; rashes; and, in rare cases, sudden loss of vision in one or both eyes; and sudden loss of hearing. Vardenafil may also cause heartburn, a stuffy or runny nose, and flu-like symptoms, while avanafil may cause back pain. This is not a full list of side effects, so be sure to discuss the risks with your doctor before starting any new medication.49,50
CostWith RedBox Rx, generic vardenafil is as low as $3 per tablet and generic avanafil is $40 per tablet with a 20-tablet order.
ED Medication Comparison Chart
This side-by-side comparison chart of all four PDE5 inhibitors — vardenafil, avanafil, tadalafil and sildenafil — can help you quickly compare dosage, onset, duration and cost through RedBox Rx.
How to Choose an ED Medication
While all four PDE5 inhibitors — vardenafil, avanafil, tadalafil and sildenafil — have demonstrated effectiveness in treating ED, there are key differences between each medication. Talk with your healthcare provider to determine the best option for you, and be sure to consider:
How often you have sex: If you're intimate frequently, a daily low-dose option like tadalafil may be a better fit, while as-needed dosing may suit less frequent activity.
How quickly you want it to work: Avanafil is one of the fastest-acting options, while the others generally take longer to kick in.
How long you want it to last: Tadalafil offers the longest window (up to 36 hours), while sildenafil, vardenafil and avanafil typically last several hours.
Sensitivity to side effects: If certain side effects are a concern, one medication may be easier to tolerate than another, so review the risks with your provider.
Your budget: Prices vary between medications, so cost may factor into your decision.
Your medical history and current medications: Share any allergies, health conditions and medications you're taking so your provider can confirm a treatment is safe for you.
Learn more about how to get ED medications on our blog or get started today by scheduling a free consultation.
How RedBox Rx can help
RedBox Rx makes it easy to get safe, discreet and affordable prescriptions for FDA-approved erectile dysfunction medications like sildenafil, tadalafil, avanafil and vardenafil.
Benefits of RedBox Rx include:
Transparent, affordable, flat rates for ED medications starting at $1 per tablet.
Free consultations with a U.S. licensed medical professional.
No insurance required. HSA and FSA eligible.
No office wait times or scheduling issues typical with physical medical practices.
Free standard shipping or expedited/overnight available.
Start your treatment today with our quick, free online ED assessment.
