Key takeaways:
Viagra (sildenafil) is a prescription phosphodiesterase 5 (PDE5) inhibitor. It’s considered a first-choice treatment for erectile dysfunction.
The usual Viagra dosage ranges from 25 mg to 100 mg by mouth, taken 30 minutes to 4 hours before sex. In addition to your age, your typical dosage can depend on side effects, health history, and other medications you’re taking.
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Viagra (sildenafil) is a phosphodiesterase 5 (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 30 minutes to 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 prescriber or pharmacist if you have questions about your Viagra dosage, which may be different from what’s covered below.
What’s the typical Viagra (sildenafil) 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 prescriber 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.
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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. Avoid high-fat foods if you need to take it with a meal or snack. Don’t take more than one Viagra dose per day.
Keep in mind that Viagra is only taken as needed prior to sex. And it will only work if you’re aroused.
Are there any sildenafil 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.
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 prescriber 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:
Interacting medication | Starting Viagra dosage |
Nitrates, such as isosorbide mononitrate (Monoket) | Avoid use |
Soluble guanylate cyclase stimulators, such as riociguat (Adempas) | Avoid use |
Alpha blockers, such as prazosin (Minipress) | 25 mg |
Erythromycin (Ery-Tab, Eryc, Eryped, E.E.S.) | 25 mg |
Azole antifungals, such as ketoconazole | 25 mg |
One 25 mg dose in a 48-hour period |
Make sure your prescriber and pharmacist have the current list of medications you’re taking. They can check for any potential drug interactions with Viagra.
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Warnings and precautions when taking Viagra (sildenafil)
Viagra is generally safe when taken as prescribed. But there are some key precautions to keep in mind:
Avoid certain medications. Never take Viagra with nitrates or medications like riociguat. These combinations can cause dangerously low blood pressure. Other medications may require additional monitoring for side effects with Viagra.
Talk to your healthcare team about your health history. Having certain health conditions can make Viagra unsafe. For example, you may need to avoid Viagra if you’ve had a recent heart attack or stroke.
Be aware of potential vision and hearing changes. In rare cases, sildenafil can cause sudden vision or hearing loss. Tell your healthcare team right away if you notice any changes in your vision or hearing.
Know the signs of serious side effects. Get emergency medical care if you experience symptoms such as chest pain, trouble breathing, or an erection lasting more than 4 hours (priapism).
Make sure your healthcare team has your complete medication list (including supplements) and medical history before starting Viagra. They can discuss the potential risks and symptoms to watch for when taking it.
What should you do if you take too much Viagra (sildenafil)?
Taking too much Viagra can be dangerous. If this happens, you may experience low blood pressure (hypotension). 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 team or Poison Control at 1-800-222-1222. And if you experience any severe side effects, go directly to the nearest ER.
How to save on Viagra (sildenafil)
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 $14.10 with a free GoodRx discount.
Save with GoodRx Care Direct. Get generic Viagra delivered directly to your door starting at $18 per month.
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.
Frequently asked questions
Yes, sildenafil does expire. Like all medications, sildenafil has an expiration date printed on the label or packaging. Sildenafil that’s expired may be less effective. So it’s best to check the expiration date and replace it if it’s expired.
Sildenafil works by relaxing blood vessels, which can lower blood pressure slightly. For most healthy people, this effect is mild. But for people living with certain heart conditions or those taking nitrates, it can cause serious problems, such as dangerously low blood pressure (hypotension). If you have a heart condition, talk to your healthcare team before taking sildenafil.
Yes, sildenafil does expire. Like all medications, sildenafil has an expiration date printed on the label or packaging. Sildenafil that’s expired may be less effective. So it’s best to check the expiration date and replace it if it’s expired.
Sildenafil works by relaxing blood vessels, which can lower blood pressure slightly. For most healthy people, this effect is mild. But for people living with certain heart conditions or those taking nitrates, it can cause serious problems, such as dangerously low blood pressure (hypotension). If you have a heart condition, talk to your healthcare team before taking sildenafil.
The bottom line
The typical Viagra (sildenafil) dosage for ED ranges from 25 mg to 100 mg once daily as needed. You can take it between 30 minutes to 4 hours before sex, and it usually works within an hour.
People over age 65 may need to start with a lower Viagra dose. This is also the case if you have severe kidney problems, liver problems, or if you’re taking interacting medications. Your prescriber will help you figure out the best Viagra dosage for you.
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References
Torrent Pharmaceuticals Limited. (2024). Sildenafil citrate- sildenafil tablet, film coated [package insert]. DailyMed.
