Viagra (Sildenafil) Dosages for Erectile Dysfunction: Your GoodRx Guide

Viagra (sildenafil) is a phosphodiesterase 5 inhibitor (PDE5 inhibitor) that comes as an oral tablet. It’s often a first-choice treatment for men with erectile dysfunction (ED). Viagra usually takes about an hour to work, but you can take it 30 minutes to 4 hours before sex. 

In this guide, we’ll review typical Viagra dosages. This includes the starting dosage and any adjustments for age, health conditions, and drug interactions. Check with your healthcare provider or pharmacist if you have questions about your Viagra dosage, which may be different from what’s covered below.

What’s the typical Viagra dosage?

The starting Viagra dosage for ED in adult men is 50 mg by mouth, taken 30 minutes to 4 hours before sex. If any Viagra side effects are bothersome, your healthcare provider may decrease your dose to 25 mg. And depending on how well it works, your dose may be increased to a maximum of 100 mg. 

Viagra generally starts working within an hour after taking it. You can take your dose with or without food. But it’ll typically work fastest if you take your dose on an empty stomach. Don’t take more than one Viagra dose per day.

Keep in mind: Viagra is only taken as needed prior to sex. And it will only work if you’re aroused.

Are there any dosage adjustments for medical conditions or interactions?

Depending on your age and health history, you may need to take a lower Viagra dosage. This is also the case if you’re taking medications that interact with Viagra.

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Dosage for adults over 65 years old

As you get older, your body may process certain medications differently. This is also the case with Viagra. If you’re over age 65, your healthcare provider may recommend 25 mg for your starting dose.

Dosage for people with kidney problems

Viagra is partially eliminated from the body through your kidneys. If your kidneys aren’t working very well, Viagra can build up in your body. This can increase the likelihood of side effects.

If you have mild to moderate kidney problems, you can generally take the usual Viagra dosage. But people with severe kidney problems may start with a 25 mg dose instead.

Dosage for people with liver problems

Viagra is broken down by enzymes (proteins) in your liver. Similar to kidney problems covered above, Viagra can build up in your body if your liver isn’t working as well. If you have liver problems, you may start with a 25 mg dose, as well.

Dosage adjustments for drug interactions

Certain medications can interact with Viagra, increasing the risk of side effects. While it’s not a complete list, a few examples can be found in the table below:

Make sure your healthcare provider and pharmacist have the current list of medications you’re taking. They can check for any potential drug interactions with Viagra.

What should you do if you take too much Viagra?

Taking too much Viagra can be dangerous. If this happens, you may experience low blood pressure (hypotension). An erection lasting longer than 4 hours (called priapism) is also possible. Priapism is considered a medical emergency. If left untreated, it can result in permanent damage to your penis.

If you think you may have taken too much Viagra, contact your healthcare provider or Poison Control at 1-800-222-1222. And if you experience any severe side effects, go directly to your nearest emergency room.

How to save on Viagra

There are many ways to save on Viagra, which is available as both a brand-name and generic medication. 

• Save with GoodRx. GoodRx can help you save over 90% off the average retail price of the generic version. Generic Viagra’s price at certain pharmacies is as low as $12.56 with a free GoodRx discount.

• Save with a copay savings card. If you’re eligible, you could save 50% off brand-name Viagra using a savings card from the manufacturer.

Why trust our experts?

Written by:

Brian Leonard, PharmD, BCACP, BCGP

Brian Leonard earned his doctorate in pharmacy from the University of Florida College of Pharmacy and is board certified in Ambulatory Care and Geriatric Pharmacy.

Edited by:

Alyssa Billingsley, PharmD

Alyssa Billingsley, PharmD, is the director of pharmacy content for GoodRx. She has over a decade of experience as a pharmacist and has worked in clinical, academic, and administrative roles.

Reviewed by:

Austin Ulrich, PharmD, BCACP

Austin Ulrich, PharmD, BCACP, is a board-certified ambulatory care clinical pharmacist. In his early career, he provided direct patient care in a variety of settings, including hospital and community pharmacies, and in a primary care clinic as a clinical pharmacist.

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