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Erectile dysfunction (ED) is a treatable condition, and various medications can help, such as sildenafil and tadalafil. The pills that people find most effective will depend on their individual needs and lifestyles.

Research shows that phosphodiesterase type 5 (PDE5) inhibitors can effectively treat ED, together with other medications, such as injections.

These drugs impede the functioning of PDE5, an enzyme within the blood vessel walls that helps control blood flow.

Following arousal, the body releases enzymes that cause blood vessels in the smooth muscles to relax, allowing for more blood flow. PDE5 inhibitors block the degradation of these enzymes, increasing blood flow and resulting in an erection.

It is important to note that a person needs to be aroused for a PDE5 inhibitor to help with ED.

This article focuses on PDE5 inhibitors. It discusses what erectile dysfunction is and what may cause it and looks at the common PDE5 medications for ED in detail.

Erectile dysfunction occurs when a person cannot develop or maintain an erection firm enough for sexual intercourse.

According to a 2022 overview of the condition, ED is common in individuals over 40 years of age.

ED can differ from one person to another. While some people can get an erection, they may not be able to maintain it, and they may not be able to get one every time they want to have sex. Others may not be able to get an erection at all.

The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) writes that ED can be a short- or long-term health concern.

Learn more about ED.

The National Health Service (NHS) in the United Kingdom reports that ED occurs due to factors such as fatigue, stress, anxiety, or alcohol consumption. However, someone who experiences ED regularly should talk with a doctor.

Possible causes of long-term ED may include:

All ED pills are available via prescription only, so a person must first speak with a doctor or healthcare professional to discuss symptoms. Some companies offer telehealth consultations. The medical professional will then decide whether ED medication is appropriate.

Examples of ED pills include:

Comparison

Below is a comparison table of these oral ED treatments.

Sildenafil
(Viagra)
Tadalafil
(Cialis)
Vardenafil
(Levitra or Staxyn)
Avanafil
(Stendra or Spedra)
Dosage options25 mg, 50 mg, 100 mg2.5 mg, 5 mg, 10 mg, 20 mg2.5 mg, 5 mg, 10 mg, 20 mg50 mg, 100 mg, 200 mg
Typical dosage50 mg10 mg as needed or 2.5 mg per day10 mg (5 mg for people 65 years or older)100 mg
When to take30–60 minutes before sex30 minutes before sex60 minutes before sex15 minutes before sex for 100 mg and 200 mg, 30 minutes before sex for 50 mg
How long it lasts4 hoursup to 36 hours4–5 hours6 hours
How to storearound room temperature, from 68–77°F (20–25°C)at 77°F (25°C)at 77°F (25°C)around room temperature, from 68–77°F (20–25°C)

Below is detailed information about the PDE5 inhibitor drugs available.

Please note that the writer of this article has not tried these products. All information presented is purely research-based and correct at the time of publication.

Medical News Today follows a strict product selection and vetting process. Learn more here.

Sildenafil (Viagra)

Sildenafil (Viagra) is common in the treatment of ED. It can also treat conditions such as pulmonary hypertension, a type of high blood pressure in the lungs.

The pills come in 25 mg, 50 mg, or 100 mg.

Some advantages of taking sildenafil for ED include:

  • Fast-acting: It starts working around 30 minutes after taking the pill.
  • Research: Clinical trials and studies confirm its effectiveness.
  • Lasting effects: Up to 4 hours.
  • Side effects: Serious side effects are rare, though they can include allergic reactions and heart problems.

Some disadvantages include:

  • Short-term use: It may only be a short-term option, as 20–50% of people who take sildenafil do so temporarily.
  • Unsuitable for some health conditions: Viagra’s prescribing information states people with cardiovascular diseases that make sexual activity unsafe should take Viagra with caution. This also applies to people with aortic stenosis, idiopathic hypertrophic subaortic stenosis, or those with severely impaired autonomic blood pressure control. The NHS states those with serious liver conditions, low blood pressure, multiple myeloma, or sickle cell anemia should speak with a doctor before taking Viagra.
  • Drug interactions: It can interact with other drugs, including some heart disease and blood pressure medications.
  • Preference: People seem to prefer an alternative drug called tadalafil, though the two drugs are equally effective, according to 2017 research.

There are also some possible side effects of sildenafil, including:

  • a stuffy or runny nose
  • hot flashes
  • headaches
  • a fever
  • nausea
  • chest pains
  • painful erections lasting several hours
  • dizziness
  • vision problems
  • indigestion

Where to buy sildenafil (Viagra)

The following companies offer sildenafil:

RomanLemonaidBlink HealthGoodRx
Coststarting from $2 per dosestarting at $2 per pillinitial cost of $10, then starting from around $17 per monthdependent on pharmacy
Available dosage20–100 mg, according to a doctor’s recommendation20 mg — doctors may recommend taking multiple pills to create a 40 mg, 60 mg, 80 mg, or 100 mg dose 20 mg, 25 mg, 50 mg, 100 mg20 mg, 25 mg, 50 mg, 100 mg

Tadalafil (Cialis)

Tadalafil (Cialis) works by increasing blood flow to the penis. Doctors also use the drug to treat high blood pressure in the lungs and enlargement of the prostate. For ED, people take it as an oral tablet.

Some advantages of tadalafil include the following:

  • Longest lasting: It is the longest lasting PDE5 drug for ED, typically lasting up to 36 hours, though some reports suggest it can last up to 72 hours.
  • Longer-term use: It is possible to take a low dose of 2.5–5 mg once per day for a longer-term solution.
  • Daily use: People who regularly engage in sexual activities may prefer taking a daily pill.
  • Increased confidence: Research suggests that people who take tadalafil experience more sexual confidence than those who do not.

However, disadvantages include the factors below:

  • Cost: Taking it every day can have a higher cost.
  • Hidden underlying ED causes: Taking it long term may prevent or delay treatment for the underlying cause of ED, which may be psychological.
  • Drug interactions: Tadalafil can interact with several types of medication, including common blood pressure drugs.

There are also possible side effects from tadalafil, including:

Where to buy tadalafil (Cialis)

Tadalafil is available to purchase from the following companies:

RomanLemonaidBlink HealthGoodRx
Cost$11–44$65 per pillinitial cost of $10, then starting from around $17 per monthdependent on pharmacy
Available dosage2.5, 5 mg, 10 mg, 20 mg5 mg, 10 mg, 20 mg2.5 mg, 5 mg, 10 mg, 20 mg2.5 mg, 5 mg, 10 mg, 20 mg

Avanafil (Stendra)

Avanafil (Stendra) is another PDE5 drug. It works similar to other drugs in its class by increasing blood flow to the penis.

Some advantages of avanafil include:

  • Fast-acting: Avanafil can start working 15–30 minutes after taking the drug.
  • Safe: Research has found that avanafil is a safe and effective ED treatment.
  • Longer lasting: Its effects can last up to 6 hours.
  • Popular with older and younger adults: An older review from 2014 found that older and younger adults both preferred taking avanafil to other PDE5 drugs due to its quick effects.

However, a disadvantage of the drug is that it is currently unavailable in generic form, making it more expensive than other PDE5 drugs.

There are also some possible side effects of taking avanafil, including:

Where to buy avanafil (Stendra)

The following companies offer avanafil (Stendra).

GoodRxBlink Health
Costdependent on pharmacystarting from around $415 for six tablets
Available dosage50 mg, 100 mg, 200 mg50 mg, 100 mg, 200 mg

Vardenafil (Levitra)

Similar to other PDE5 medications for ED, vardenafil (Levitra) works by increasing blood flow to the penis.

Some advantages of vardenafil include clinical trials finding it to be effective. In addition, unlike avanafil, vardenafil is available in a more affordable, generic form.

Its disadvantages are that the drug can take comparatively longer to start working, and a person needs to take it 1 hour before sexual activity. In addition, compared with tadalafil and sildenafil, vardenafil has no unique advantages.

Some possible side effects of vardenafil include:

  • a stuffy or runny nose
  • facial flushing
  • headaches
  • stomach problems
  • back pain
  • vision problems

Where to purchase vardenafil (Levitra)

Levitra and its generic version, vardenafil, are only available to purchase once a doctor has prescribed them.

At the time of publication, four 2.5-mg tablets cost between $29 and $178, while thirty 20-mg tablets can cost up to $442.

People can purchase ED medications at a pharmacy, provided they have a valid prescription from a doctor or healthcare professional.

Alternatively, they can purchase them online, usually after completing an online questionnaire reviewed by a doctor or healthcare team.

Individuals should check reviews of the health company before purchasing a product and consult a doctor or pharmacist if they have any concerns.

Research suggests that ED pills are safe and effective when someone takes them under a doctor’s supervision.

Results may vary between individuals, but a 2021 review found that 50 mg and 100 mg sildenafil pills were most effective compared to a placebo. However, there is currently insufficient data to compare the different PDE5 inhibitor pills.

ED pills are typically taken around 1 hour before sex. However, instructions may vary between medications.

Some pills require people to take them with food, and other pills on an empty stomach.

A person should always follow the instructions before taking any prescription medication.

While ED medications are often effective, some individuals may prefer to try other methods of ED treatment, including:

  • Diet, exercise, and healthy habits: This involves staying active, following a nutritious diet, and avoiding smoking.
  • Psychotherapy: Dealing with underlying emotional or psychological issues may help ease ED.
  • Vacuum devices: These devices use suction to bring blood into the penis to achieve an erection.
  • ED rings: These devices use constriction to maintain an erection. A person puts this device around the base of their penis. An example of this is Eddie by Giddy. The product comes in different sizes, and the website provides full instructions. Learn more about the Eddie product here.
  • Surgery: When all other treatments are ineffective, a doctor may recommend a surgical implant to help a person achieve or maintain their erections.

Read about some of the best available ED rings.

Individuals should keep regular contact with their doctor if they experience prolonged ED, as there may be an underlying health condition that needs exploration.

After taking ED pills, a person may experience side effects such as headaches, indigestion, dizziness, or a stuffy nose. These are common and usually subside over time.

However, a person should consult their doctor if these side effects become severe or persistent.

Although rare, ED medications can also cause more serious side effects, including:

  • chest pain
  • vision problems
  • hearing loss
  • seizures
  • skin reactions, including itchy, red, or swollen skin
  • priapism, a painful erection lasting more than 4 hours

If someone experiences any of these side effects, they should discontinue using the drug immediately and seek medical advice.

Symptoms, such as wheezing, tightness in the chest or throat, difficulty breathing, and swelling of the mouth, throat, lips, or tongue, may have links with anaphylaxis, a life threatening allergic reaction.

If a person notices any symptoms of anaphylaxis, they should call 911 or go to the nearest emergency room.

Some people should not take ED medications or should take them with caution. Some examples include:

  • Those avoiding sexual activity: Individuals with recommendations from a healthcare professional to avoid sexual activity due to health problems should not take any ED drugs.
  • Grapefruit: A person should not take PDE5 inhibitors with grapefruit or grapefruit juice as it may affect how the drugs work.
  • History of adverse reactions: People who previously experienced sudden hearing loss or vision problems should not use the drugs. If someone new to ED drugs experiences these symptoms, they should discontinue use and seek immediate medical attention.

ED medications may also interact with other drugs, including:

  • nitrates
  • certain blood pressure medications
  • alpha-blockers
  • guanylate cyclase stimulators
  • certain antifungal medications and antibiotics

Additionally, individuals taking HIV protease inhibitors, such as ritonavir (Norvir), should not take avanafil. The Food and Drug Administration (FDA) advises that people with liver or kidney problems do not take avanafil.

Those who experience an erection lasting more than 4 hours should also consult their doctor.

Herbal supplements

A person should be cautious when considering herbal supplements that claim to help with ED. This is because there is very little research to prove their effectiveness, and the FDA has not approved these products.

Specifically, the FDA advises against buying “herbal Viagra” as it contains undeclared ingredients that may negatively interact with some prescription drugs.

Here are some common questions about ED and its medications.

What causes ED?

ED can develop due to several mental or emotional issues, including stress, anxiety, depression, and relationship issues.

There are also many physical causes of ED, such as heart disease, diabetes, multiple sclerosis, and high blood pressure or cholesterol levels. Smoking tobacco, consuming high amounts of alcohol, and taking certain medications could also contribute to the condition.

How do you know whether ED is physical or mental?

A doctor or healthcare professional can determine whether a person’s ED is due to physical or mental health factors by collecting information about their medical and sexual history. They may also conduct a physical exam.

Healthcare professionals may also recommend an overnight erection test, which involves placing a device around the penis overnight to measure the number of nocturnal erections. If a person can achieve a set number of erections at night, it may indicate that their ED is due to psychological problems rather than physical conditions.

A person may also undergo an intracavernosal test. During this test, doctors inject a small amount of medication into the base of the penis to cause an erection. Imaging techniques, such as an ultrasound, can also help determine whether there are any problems with blood flow.

How much do pills for ED cost?

To get a pill for ED, a person needs a prescription from a doctor or an online telehealth service. Once the prescription is ready, the cost will depend on whether an individual’s insurance plan covers all or some of the costs.

Typically, generic versions of ED pills, such as sildenafil, cost significantly less than the brand-name versions, such as Viagra.

How effective are ED medications?

Each of the medications in this article is effective in treating ED. However, according to research, avanafil may be the fastest working medication with the fewest visual side effects.

It is important to note that for any of these medications to work, a person requires sexual stimulation.

Which ED medication is best?

The type of ED medication a person should take depends on individual needs. Each medication type may have different side effects, dosage requirements, and times to work properly.

Individuals should consider these factors before trying these medications.

Which ED drug is safest?

All four of the main ED pills — sildenafil (Viagra), tadalafil (Cialis), vardenafil (Levitra), and avanafil (Stendra) — are safe for most people to use. These drugs are FDA-approved for use in ED. A person must ensure their medication is doctor-prescribed and comes from a legitimate source.

Is it safe to combine ED treatments?

Health experts recommend against combining ED medications unless a doctor advises otherwise.

If one medication for ED is not working, a person should consult their doctor to determine whether alternative treatment options may work better or if other underlying factors may contribute to ED.

What is the most popular ED pill?

The most commonly prescribed erectile dysfunction medications are sildenafil (Viagra) and tadalafil (Cialis).

Can you get ED medications over the counter?

Most ED medications require a prescription from a doctor. However, people can buy ED devices such as vacuums and rings online.

Several medications can treat ED, and many drugs — including those in this article — work by blocking the PDE5 enzyme, increasing blood flow to the penis.

The best choice of ED medication will depend on various factors. For example, people who have regular sex may prefer taking tadalafil, which is available as a daily pill. Meanwhile, others may prefer medications they can take just before having sex, such as sildenafil, avanafil, or vardenafil.

However, it is important for a person to consult a doctor before taking ED medication and only use it as directed to help prevent adverse side effects.