Sildenafil 20 mg: Effectiveness & Side Effects

When it comes to penises, size isn’t everything. But when it comes to erectile dysfunction (ED) medications, dose size can make a difference.

Sildenafil citrate is a generic drug found in several types of prescription meds. It’s most popularly known as the active ingredient in Viagra® and a treatment for ED, but sildenafil is also sold as Revatio®, a medication marketed for treating pulmonary arterial hypertension.

Depending on your health needs, your dosage of Viagra might be 25 milligrams (mg), 50 mg, or 100 mg. While sildenafil 20 mg tablets do exist, they’re FDA-approved for pulmonary arterial hypertension, not ED.

Keep reading to find out if a sildenafil 20 mg dosage for erectile dysfunction exists, the most common sildenafil dosages, potential side effects, and more.

Most people assume they know what Viagra does — it causes erections, right? While this is true, a few uses of sildenafil extend beyond improving sexual activity.

Besides being sold as Viagra, sildenafil is the active ingredient in Revatio. As we mentioned above, this brand-name drug is approved by the U.S. Food and Drug Administration (FDA) for treating pulmonary hypertension, a type of high blood pressure affecting arteries in the lungs and the right side of the heart. Revatio can prevent this condition from worsening.

Sildenafil may also be used off-label to treat:

• Raynaud phenomenon (narrowing blood vessels in extremities such as fingers and toes)

• Female sexual arousal disorder

• Mountain sickness

Sildenafil has a variety of uses because it’s a phosphodiesterase type 5 (PDE5) inhibitor. PDE5 inhibitors are medications that improve blood flow to certain tissues by widening the blood vessels. They’re best known for increasing blood flow to the penis, allowing for erections upon sexual stimulation.

At the moment, 20 mg Viagra does not exist — but you can get Revatio in a 20 mg tablet, and it can be prescribed off-label for ED.

In the same way that you can get generic Viagra as a 25 mg sildenafil tablet, you can also get generic Revatio as a 20 mg sildenafil tablet. It may be marked as a c89 pill or described as generic Viagra because these drugs both contain sildenafil. The only chemical difference is the dosage.

If you’re taking a 20 mg generic Viagra white pill, chances are you’re actually taking generic Revatio.

Viagra is available in dosages of 25 mg, 50 mg, and 100 mg. Currently, 100 mg sildenafil is the highest dosage approved by the FDA. Revatio is available in 20 mg tablets.

There’s no one-size-fits-all solution when it comes to the ideal sildenafil dosage. Your dosage will depend on your health needs and the reason you’re taking the medication.

You might assume a higher dosage of sildenafil leads to a firmer erection or better sex, but this isn’t always the case. In fact, taking too much sildenafil can lead to some serious side effects, like a sudden decrease in blood pressure.

It’s best to stick with your prescribed dosage and follow the patient information leaflet your healthcare provider gives you. If you find that a particular dose isn’t working as well as you had hoped, make another appointment with your provider and ask if you can revisit your dosage or explore other treatment options.

To get the best results from Viagra, it’s important to take the right dosage.

As mentioned, 20 mg sildenafil is FDA-approved for pulmonary arterial hypertension, not erectile dysfunction. If you take a 20 mg dose of sildenafil, it might improve your erections, but it might not.

Although Viagra can come in as small a dose as 25 mg, the 50 mg tablets are usually the starting dosage. If you experience uncomfortable side effects, your dosage could decrease to 25 mg. Patients older than 65 and those with kidney or liver problems may start on a 25 mg dose.

Viagra is considered an effective treatment for erectile dysfunction, but its efficacy depends on the dosage. In clinical trials, 63 percent of participants who took 25 mg sildenafil reported an improvement in their erections, compared to 74 percent of those who took 50 mg and 82 percent of those who took 100 mg.

With that said, other erectile dysfunction treatments — like tadalafil (Cialis®) and vardenafil (Levitra®) — are available in a 20 mg dosage, but these are different medications, so their dosages aren’t directly comparable to sildenafil.

Whether you’re experiencing poor erectile function or have a cardiovascular condition, sildenafil can drastically improve your symptoms.

The medication is generally safe, and research suggests it won’t cause any long-term health issues. But that doesn’t mean it’s completely without risks or side effects.

Common side effects of sildenafil include:

• Headache

• Flushing

• Back pain

• Blurred vision

• Muscle pain

• Nausea

• Dizziness

• Rash

• Nasal congestion

If you experience priapism (a prolonged, painful erection) or any other serious adverse effects — like shortness of breath, irregular heartbeat, or loss of vision — seek emergency medical attention.

Sildenafil might also be dangerous for people with a history of certain medical conditions, including:

• Allergic reactions to Viagra or any PDE5 inhibitor

• Blood problems like hemophilia, leukemia, or sickle cell anemia

• Conditions affecting penis shape, like Peyronie’s disease or a curved penis

• Eye problems, such as retinitis pigmentosa, vision loss, or NAION (non-arteritic anterior ischemic optic neuropathy)

• Heart problems (e.g., having had a heart attack or stroke)

• High or low blood pressure

• Liver disease

• Kidney disease

• Peptic ulcers

There are a few sildenafil drug interactions you need to look out for, too. An interaction is when one drug, like sildenafil, causes a negative reaction when mixed with another medication, supplement, or substance.

Possible sildenafil interactions include:

• Other PDE5 inhibitors, including erectile dysfunction medications like tadalafil (Cialis), avanafil (Stendra®), or vardenafil (Levitra or Staxyn®)

• Nitrates for angina (chest pain), such as nitroglycerin (Nitrostat® or NitroMist®), isosorbide mononitrate, and isosorbide dinitrate (Isordil®)

• Blood pressure drugs and alpha-blockers

• Poppers (recreational drugs containing nitrites)

Sildenafil may also have minor interactions with the following substances:

• Certain antifungal drugs, such as ketoconazole and itraconazole

• Some antibiotics, like erythromycin and clarithromycin (Biaxin®)

• HIV protease inhibitors, like saquinavir mesylate (Invirase®) and ritonavir (Norvir®)

If you’ve been prescribed any of the above medications, it’s a good idea to ask a healthcare professional whether you can safely take them with sildenafil.

Also, while you can mix Viagra with alcohol, it’s a good idea to pace yourself and only have one or two drinks.

Erectile dysfunction is just one condition sildenafil can help address. The dosage of sildenafil you use will depend on whether you’re taking it for ED, a cardiovascular condition, or for another reason. Remember:

• A 20 mg dose of sildenafil is FDA-approved for pulmonary arterial hypertension. That said, it is sometimes prescribed off-label (at the 20 mg dose and at multiples of 20 mg, including 40 mg, 60 mg, 80 mg, and 100 mg) for ED. If you’re wondering How many 20 mg sildenafil should I take for ED?, that’s for you and your provider to figure out.

• For ED, the typical starting sildenafil dosage is 50 mg. Though it can be increased or decreased as needed, licensed prescribers usually start patients on a 50 mg tablet.

• There are alternative erectile dysfunction treatments. If the side effects of sildenafil are putting you off, or if it’s just not working as well as you’d hoped, you may want to look into tadalafil (Cialis), Stendra (avanafil), or our chewable ED hard mints.

Our guide on how to take sildenafil for erectile dysfunction covers some need-to-know information about Viagra, but it’s no replacement for speaking with a licensed healthcare professional.

If you’re concerned about your sildenafil dosage or experiencing uncomfortable side effects, you should seek medical advice from a healthcare professional.

You can even start today by booking an online appointment with a healthcare practitioner through our telehealth platform.