Any erectile dysfunction (ED) pills that are available with a prescription at a local pharmacy are generally safe for most people. However, if a person is taking nitrates for an underlying heart condition, they should avoid ED pills.

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ED pills are phosphodiesterase-5 (PDE5) inhibitors. A person could experience an unsafe drop in blood pressure if they take these alongside nitrates.

PDE5 inhibitors help a person achieve an erection by relaxing the smooth muscle in the walls of the blood vessels. This dilation allows the penis to fill with blood.

In this article, we talk about the different types of ED pills, their safety and side effects, and the differences between generic and branded options.

There are four main types of ED pills that the Food and Drug Administration (FDA) have approved as treatments in the United States.

They are:

  • sildenafil (Viagra)
  • tadalafil (Cialis)
  • vardenafil (Levitra)
  • avanafil (Stendra)


Sildenafil, more commonly known by the brand name Viagra, is often the first-line treatment for ED. Doctors tend to like trying Viagra before other treatments because it has been on the market for so long, which means that its side effects and interactions are well-known.

A lot of doctors prescribe a Viagra dose of 50 milligrams (mg), which a person should ideally take about 1 hour before sexual activity. However, it should be effective anywhere from 30 minutes to 4 hours before sex.

A person should avoid taking Viagra with meals as this will slow down its absorption rate and delay its effect. People should also avoid taking Viagra with alcohol.

It usually takes 30–120 minutes for Viagra to start working after a person takes it.


The initial dose for Cilias is 10 mg, and a person can take it as necessary for sexual activity. They can decrease the dose to a minimum of 5 mg or increase it to a maximum of 20 mg, depending on what they need and tolerate.

Cialis behaves slightly differently than other ED medications. It does not break down as quickly, so it stays in the body for longer.

A doctor may prescribe Cialis at a 5-mg dose to treat benign prostatic hyperplasia. It is, therefore, a good option for treating the symptoms of both an enlarged prostate and ED at the same time.

The authors of a 2017 review that looked at 16 trials comparing Cialis with Viagra observed that people preferred taking Cialis due to people feeling less pressure over when to take the drug, leading to an increase in sexual confidence.


Levitra is the brand name of vardenafil. Doctors recommend 10 mg as an initial dose, which a person should take 1 hour before sexual activity. The maximum dose is 20 mg, with the minimum being 5 mg.

A doctor may adjust the dose depending on the medication’s effect on the person. A person should take Levitra no more than once per day, with or without food.

Staxyn is a dissolvable tablet that contains vardenafil. According to the FDA, it is “not interchangeable” with Levitra as it has a stronger effect on the body.

Staxyn comes in 10-mg tablets that dissolve on the tongue. A person can take the tablet with or without food about 1 hour before sexual activity, but it is important to take no more than one a day.


The FDA has approved three doses of Stendra: 50 mg, 100 mg, and 200 mg. A person typically takes Stendra 30 minutes before sexual activity. The starting dose is often 100 mg, but a person can either increase it to 200 mg or decrease it to 50 mg, depending on how they respond to treatment.

For more research-backed information and resources for men’s health, please visit our dedicated hub.

The medical community considers ED pills generally safe for most people who are otherwise healthy enough for sexual activity.

As with any medication, there are potential side effects that a person may experience. ED pills can also interact with other medications, such as nitrates.

It is important not to take ED pills with nitrates such as nitroglycerin, because the drugs can interact to cause dangerously low blood pressure.

People living with urinary problems should leave 4 hours between taking alpha-blockers and ED medication. Alpha-blockers include doxazosin (Cardura) and prazosin (Minipress).

Each pill for ED has a risk of mild side effects.

Common side effects include:

If a person has an erection that lasts longer than 4 hours, they should seek immediate medical attention. A long lasting erection can cause permanent damage to the penis.

Experts estimate that 70% of people taking ED medications will achieve an erection good enough for sexual intercourse.

The quality of the erection, pleasure, and sensations will vary depending on other preexisting conditions, such as nerve damage from surgery or diabetes. However, those who can achieve an erection should have one that lasts long enough for them to ejaculate.

Learn more about the best ED pills for diabetes here.

How long ED pills take to work will vary among individuals. Most manufacturers suggest that a person should take their ED treatment 15–60 minutes before sexual activity.

For the most effective erection, experts recommend that a person also engages in foreplay with their partner to help stimulate arousal.

Viagra, Levitra, Staxyn, and Stendra provide more of an on-demand sexual experience.

Cialis, on the other hand, stays in the body for longer and takes more time to reach its full effect. As a result, it is good for people who prefer the reliability of a daily-use product with longer-lasting effects.

Brand-name medications are better known than their generic counterparts due to advertising. They appear on the market first and tend to be more expensive than the generic equivalent. Newer medications typically do not have generic versions because the release of their patent rights takes time.

Generics are a copy of the branded equivalent. A generic form of medication works in exactly the same way as the branded drug and shares the same side effects and dosage instructions. A person’s insurance company may substitute a generic version of the branded equivalent to save money.

A person should always purchase their medications from a reputable pharmacy. ED medications are only available with a prescription. If they are available online with no need for a prescription, people should not purchase them.

Illegally sold ED pills could come from an unreputable manufacturing source and may contain a dangerous combination of ingredients.

Here we answer some common questions about these medications.

Which erectile dysfunction drug has the least side effects?

All ED drugs can cause side effects.

However, sildenafil is usually the first drug that doctors prescribe.

What is the number one erectile dysfunction pill?

A healthcare professional will help a person decides the best erectile dysfunction pill for their circumstances.

Things to consider when choosing the best erectile dysfunction pill include the cost, side effects, formulation, how frequently a person needs to take the medication, and whether a person is happy using generic or brand-name drugs.

What is the best ED medicine for seniors?

Research suggests that the first step in treating ED in seniors is to change lifestyle factors, such as quitting smoking, losing weight if necessary, and exercising regularly.

PDE5 inhibitors, such as sildenafil and tadalafil, are common medications to help ease ED symptoms in older people. This form of medication is safe for seniors unless they also take nitrates or have a high risk of cardiovascular disease that requires exercise restriction.

How can I regain erectile strength?

There are several methods a person may use to have and maintain an erection.

Lifestyle changes such as exercising regularly, eating a healthy diet, limiting alcohol consumption, and managing any conditions such as high blood pressure and diabetes may help reduce ED symptoms.

Some people may find that penis pumps help maintain erections. A 2018 study found that 77% of people and their partners were satisfied with the outcome after using these devices.

However, people should always speak with a healthcare professional to determine whether these devices are suitable for their needs.

ED medications are generally safe and have only mild side effects. The medications mostly work the same way and help a person achieve an erection for sexual activity.

People should review all their medications with a doctor and discuss safe options if they are taking alpha-blockers or nitrates. This is important because if a person combines these medicines, it could cause an unsafe drop in blood pressure.