Phosphodiesterase 5 Inhibitor

Sildenafil Oral Suspension

What is sildenafil?

Sildenafil is a phosphodiesterase inhibitor better known by the brand name Viagra. It is used to treat erectile dysfunction in adult males and to open the blood vessels in arteries leading to the lungs.

What is sildenafil used for?

Erectile dysfunction

Clinical research strongly supports the use of sildenafil in treating erectile dysfunction. Studies have found that close to 100% of men were satisfied with using sildenafil to treat their erectile dysfunction, and found that it improved their ability to have sex.

Pulmonary Arterial Hypertension (PAH)

Studies show that sildenafil can safely and effectively reduce blood pressure in the pulmonary arteries and WHO functional class in individuals with PAH.

How does sildenafil work?

Sildenafil works by blocking the PDE5 enzyme and relaxing the blood vessels. In PAH, this allows blood vessels to pass oxygen along the arteries more easily, improving the function of the respiratory system.

Similarly, when used to treat erectile dysfunction, sildenafil increases blood flow to the penis, improving its function and allowing men with the disorder to sustain an erection.

What is the recommended dosage for sildenafil?

The recommended starting dose for treating erectile dysfunction with sildenafil is 50mg one hour before intercourse. Many men later increase this quantity to 100mg for full results, so one study found that 100mg might be the more effective starting dose.

Over 65s should take a lower dose as recommended by their doctor. Usually, 25mg per day is recommended.

Whatever the starting dose, a maximum of 100mg is recommended to diminish the chance of experiencing side effects. Research has found that large doses of 200mg are effective in those who are not responsive to lower doses but with an increased chance of side effects.

For treating PAH, 5 to 20mg 3 times a day is recommended. Children should not use sildenafil for erectile dysfunction and should only take it for PAH under the close guidance of a doctor.

Sildenafil Side Effects

Sildenafil is safe to use, but it can produce some side effects. Side effects are not common but include:

  • Bladder, chest or stomach pain
  • Painful or more frequent urination
  • Cloudy or bloody urine
  • Drowsiness and dizziness
  • Anxiety
  • Blurred vision
  • Seizures
  • Fever
  • Nausea and drowsiness
  • Photosensitivity
  • Rash
  • Breathing difficulties including worsening asthma
  • Cold and flu symptoms
  • Stomach problems (diarrhea, vomiting, cramps)


How long does sildenafil last?

Sildenafil can last up to 4 hours, but it works best from one hour after taking.

How long does it take for sildenafil to work?

Sildenafil takes effect 30 minutes to 1 hour to start working.

How to take sildenafil?

Sildenafil is taken orally as a tablet.

Does sildenafil lower blood pressure?

Sildenafil lowers blood pressure slightly, which is beneficial to those with PAH but unlikely to affect anyone else.

Is sildenafil as good as viagra?

Sildenafil is the generic name for the same drug, so works the same as Viagra for a lower price.

Can women take sildenafil?

Sildenafil has not been tested on women and is not recommended for their use.

Can I take 200 mg of sildenafil?

You should speak to your doctor before taking any medication other than how instructed.

How long does sildenafil stay in your system?

Sildenafil stays working for 4 hours, after which time half the drug has left your bloodstream. After 24 hours, almost all traces will be gone.

Does sildenafil expire?

Yes. All medication expires so make sure your medication is within date to ensure it works properly.

When to take sildenafil?

Sildenafil takes up to 1 hour to work, so take it an hour before expected intercourse.

What happens if you take too much sildenafil?

Too much sildenafil will increase the intensity and likeliness of side effects.

Does sildenafil make you last longer?

Some research has found that sildenafil can prolong ejaculation, but more is needed to say for definite.

Can you take sildenafil daily?

Yes. Sildenafil is safe to take every day.

Does sildenafil make you bigger?

No. Sildenafil cannot make your penis bigger, but it can make it harder which might make it look bigger while you have an erection.

Can you drink alcohol with sildenafil?

Sildenafil can cause inebriation-like behavior, so it is best not to overuse alcohol while taking it.

Is sildenafil a controlled substance?

No. Sildenafil is not a controlled substance.

Is sildenafil a blood thinner?

No. Sildenafil is not a blood thinner, so you can take aspirin at the same time.

Is sildenafil covered by insurance?

Sildenafil is usually covered by insurance, but check with your provider.

Do you take sildenafil with food?

No. Taking sildenafil with food can reduce its effectiveness.

Does sildenafil cause cancer?

Sildenafil is safe to take but has been linked to some types of melanoma. Speak to your doctor if you are worried or if you experience any side effects.

Is revatio the same as sildenafil?

Revatio is a lower dose of sildenafil than Viagra.

Why is sildenafil cheaper than viagra?

Sildenafil is the generic name for the drug Viagra, which is why it is cheaper.

Is there any difference between viagra and sildenafil?

No. The only difference between Viagra and sildenafil is the branding (and the subsequent cost).

Does sildenafil work the first time?

Yes. Sildenafil should work within 1 hour of taking it the first time. If it doesn’t, speak to your doctor about increasing your dose.

Does sildenafil raise blood sugar?

There is some research to suggest that sildenafil can increase insulin sensitivity in people with prediabetes, which could help prevent them from developing type 2 diabetes. More research is needed for this to be used clinically.

Sildenafil contraindicated conditions:

Sildenafil desired effects:

  • Penile Venous Vasodilation
  • Pulmonary Venous Vasodilation

Sildenafil drug classes:

  • Phosphodiesterase 5 Inhibitor

Sildenafil pharmacologic actions:

  • Vasodilator Agents
  • Phosphodiesterase 5 Inhibitors
  • Urological Agents

Sildenafil mechanism of action:

  • Phosphodiesterase 5 Inhibitors
  • treatable

The content offered on is intended for informational purposes only and not as medical advice. For medical advice you should consult an appropriately licensed and qualified medical professional. If you are experiencing acute or distressing symptoms or life threatening symptoms you should immediately call 911 and/or go to the nearest emergency medical facility.

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Last updated: 10/14/2022, 10:16:17 PM