What’s the Safest Drug for Erectile Dysfunction?

By Irmanie Hemphill, MD, FAAFP
Medically reviewed checkmarkMedically reviewed
April 14, 2021

If you suffer from erectile dysfunction (ED), you’re not alone. An estimated 18 million men in the US live with ED. Though common, ED can place an unwanted burden on your intimate relationships as well as on your physical and emotional health. Thankfully, medications approved by the Food and Drug Administration (FDA) have been shown to effectively treat ED in most men.  

In this article, I’ll describe three of the most common FDA-approved medications, as well as their respective doses, costs, and potential side effects. I’ll also cover how long each medication lasts, which medications are safest, and which medical conditions can affect the medication.

For most men, ED medications are a safe and effective way to treat ED. Medication is only available via prescription, so it’s important to talk to your doctor to determine which medication, if any, is right for you. 

How Does ED Medication Work?

All of the available ED medications are phosphodiesterase-5 (PDE5) inhibitors, which work by enhancing the effects of nitric oxide to relax the penile muscles, expand blood vessels that go into the penis, and improve penile blood flow—all of which works to help men get and maintain better erections

When used correctly by healthy individuals, ED medications are safe and may help men secure more satisfying sex lives.

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What Are the Different ED Medications Available?

Currently, there are four main types of ED medications approved by the FDA. Here, we’ll describe three of those medications: sildenafil (Viagra), tadalafil (Cialis), and vardenafil (Levitra).

Sildenafil (Viagra)

Sildenafil is the first-line medication offered by many doctors because it’s been on the market longest and its side effects and drug interactions are well known.  

Sildenafil is designed for use as needed, meaning you’ll need to take it shortly before sexual activity. It can take anywhere from 30 minutes to an hour to go into effect, and it stays in your system for 4-5 hours.

Tadalafil (Cialis)

Tadalafil is another popular ED medication. Unlike sildenafil, tadalafil stays in the body for up to 36 hours and can help men become erect anytime during that window. 

Vardenafil (Levitra)

Vardenafil works similarly to sildenafil but requires a lower dosage. It also lasts about 4-5 hours in your system.


The right dosage for you depends on the medication your doctor recommends. It’s important to note that regardless of which medication you use, it’s unlikely to work well on its own—sexual stimulation is still required to have the desired effect.

  • Sildenafil (Viagra): The recommended dose is 50 mg, which typically takes 30 minutes to an hour to take effect. It’s best taken on an empty stomach 1-4 hours before sexual activity and will last in your system for 4-5 hours.
  • Tadalafil (Cialis): The recommended dose is 10 mg, which takes 30 minutes to two hours to take effect. It does not require an empty stomach for consumption and can last in your system for up to 36 hours.
  • Vardenafil (Levitra): 10 mg is the recommended initial dose, though some doctors will prescribe anywhere from 5-20 mg. It will take 30 minutes to two hours to take effect and can be taken with or without food, one hour before sexual activity. It can last in your system for about 4-5 hours.


The cost of ED medications varies depending on the specific medication and your insurance coverage. In general, brand name medications will cost more than generic. 

For example, Viagra can cost around $70 per pill, while the generic sildenafil will cost closer to $40 per pill at your standard pharmacy. You can get sildenafil from K Health for as low as $1.80 per pill. Cialis can cost $29 per pill, while tadalafil is closer to $8 per pill (at K Health, tadalafil is available for as low as $0.90 per pill. Levitra and its generic version vardenafil are the most expensive, at around $90 per pill.

Side Effects

The most common side effects of all three ED medications include:

If you experience an erection that lasts longer than four hours or any vision problems, contact your healthcare provider immediately.

In addition to the general side effects listed above, some side effects are specific to each medication:

  • Sildenafil (Viagra): Additional side effects of sildenafil can include runny nose, indigestion, muscle pain, back pain, and rash.
  • Tadalafil (Cialis): Additional side effects of tadalafil can include back pain and muscle aches.
  • Vardenafil (Levitra): Additional side effects of vardenafil can include a runny nose.

Which ED medication has the least side effects?

According to the Boston University School of Medicine, vardenafil (Levitra) may have the least potential for side effects because it’s 10 times more biochemically potent than sildenafil (Viagra) and therefore requires a lower dose to facilitate an erection.

However, it’s important to keep in mind that each person’s reaction to medication varies, and the same medication that causes no side effects for one person can cause multiple side effects for someone else.

How Long Do ED Pills Last?

Each ED medication breaks down at a different rate in the body. Sildenafil (Viagra) and vardenafil (Levitra) can stay active in your body for up to five hours, while tadalafil (Cialis) can stay active for up to 36 hours.

If you’re planning to regularly have sex more than once a day, tadalafil (Cialis) may be the most effective choice for you.

Which ED Pill Is Safest?

As medications approved by the FDA, all three of the ED drugs mentioned above have undergone thorough clinical testing to ensure they’re safe to use. 

Generic vs. branded—is there a difference?

The difference between generic and branded medication comes down to advertising. Though the components, side effects, and dosage instructions are the same, branded medication emerges to market first, making it more recognizable by name and generally more expensive.

As long as you source your medication through a reputable pharmacy and with a legitimate prescription, you should consider the medication effective regardless of whether it’s generic or branded.

Unsure which medication is right for you?

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Which Conditions May Affect Your ED Medication?

As with all medications, if you’re considering using ED medications, be aware of certain drug interactions and medical conditions. 

  • Hypertension: Alpha blockers and nitrates used to treat hypertension can interact with ED medication to produce dangerous side effects.
  • Heart health: Because nitrates can cause a negative reaction when combined with ED medication, if you take nitrates for an underlying heart condition, you should avoid PDE5 inhibitors. What’s more, people with heart disease are at the greatest risk for having a heart attack or stroke as a result of taking ED medication and are therefore not recommended to use ED medication.
  • Blood pressure: If you have low blood pressure, high blood pressure, coronary artery disease, arrhythmias, or have had heart attacks or strokes in the past, ED medication may not be safe for you. Speak to your healthcare provider.
  • Conditions that require nitroglycerin-based medication: If you take a nitroglycerin-based medication for angina or coronary artery disease, talk to your healthcare provider to determine whether ED medication is safe.

How K Health Can Help 

Did you know you can have a primary care provider online?

Check your symptoms, explore conditions and treatments, and if needed, text with a healthcare provider in minutes through K Health. 

K Health’s AI-powered app is based on 20 years of clinical data.

Frequently Asked Questions

What is the safest erectile dysfunction drug?
All ED medications available on the market have been approved by the FDA, which means they have undergone thorough clinical testing to ensure that they’re safe to use.
Can you cure erectile dysfunction at home?
With the right medication, you can effectively treat erectile dysfunction at home. Depending on the specific cause of your ED, though, the right diagnosis and course of treatment may help cure ED without the use of ED medication. Reach out to your healthcare provider for more information.
Which drugs can cause erectile dysfunction?
If you suspect a current medication may be causing your erectile dysfunction, speak to your doctor. Drugs that can cause erection problems include antidepressants, psychiatric medicines, antihistamines, high blood pressure medications, beta blockers, chemotherapy, hormonal medicines, and some recreational drugs.
What is the best drug for erectile dysfunction?
The best drug to treat your erectile dysfunction is the medication that your doctor recommends.

K Health articles are all written and reviewed by MDs, PhDs, NPs, or PharmDs and are for informational purposes only. This information does not constitute and should not be relied on for professional medical advice. Always talk to your doctor about the risks and benefits of any treatment.

Irmanie Hemphill, MD, FAAFP

Dr. Hemphill is an award winning primary care physician with an MD from Florida State University College of Medicine. She completed her residency at Halifax Medical Center.

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