Clinical Pharmacology of High-Dose Sildenafil

Too low of a Viagra dosage and your erections may not be as firm or reliable as they could be. Meanwhile, taking too high a dosage of Viagra can increase your risk of side effects.

What other drugs will affect Viagra?

Cells in your arteries normally release nitric oxide, which, via molecular messengers including cGMP, sends instructions to muscle proteins to relax. This causes increased blood flow into your penis, which causes an erection. An enzyme called PDE-5 normally breaks down that cGMP, which reverses that relaxation, allowing your erection to subside. Sildenafil, a PDE-5 inhibitor, helps maintain that erection instead. There are some situations where you should not take sildenafil.

Professional resources

You’re taking medications known as nitrates You’re taking medications known as nitrates You’re taking amyl nitrites (also known as “poppers”) You’re taking amyl nitrites (also known as “poppers”) You’re taking medications known as protease inhibitors You’re taking medications known as protease inhibitors You’re taking medications known as alpha-blockers You’re taking medications known as alpha-blockers You’re already taking sildenafil or any other PDE5 inhibitor in another form You’re already taking sildenafil or any other PDE5 inhibitor in another form You have any heart, liver or kidney problems You have any heart, liver or kidney problems You are taking medications for pulmonary arterial hypertension You are taking medications for pulmonary arterial hypertension You’re under the age of 18 You’re under the age of 18 The recommended starting dose is 50 mg. You shouldn’t take this more than once within a 24 hour period. Taking it more than once a day will increase the chance of side effects. If, after taking sildenafil, you feel the effect is too strong or too weak, you should talk to your doctor or pharmacist who may suggest an adjusted dosage for you or an alternative treatment. You should not take sildenafil film-coated tablets in combination with sildenafil oro-dispersible tablets.

Regional issues

Take your sildenafil about an hour before you plan to have sex. Swallow the tablet whole with a glass of water. You can take it with or without food, but you might find that the effect takes longer to start if you’ve eaten heavily. Alcohol can interfere with your ability to get an erection (we’ve written about it in detail here), so to maximise the benefit of sildenafil, it’s best to give the beer a miss. Grapefruit juice may increase the incidence of unwanted side effects of sildenafil. So, how much Viagra should you take the first time?

That’s a question your healthcare provider should be able to answer since it varies from person to person.

Before Using

The effects of sildenafil last approximately four hours, which means your erectile function is improved for four hours. The effects of sildenafil become evident when you are sexually stimulated or aroused. You should not have an erection for four hours - a prolonged and painful erection (priapism) is a surgical emergency, and you should seek sildenafil 130mg urgent medical attention should this happen. Most people feel the effect of sildenafil in 45 minutes or so. You’ll need to have sexual stimulation or feel sexually aroused to get an erection.

Sildenafil Oral Film for ED

If nothing happens, or if not enough happens, you should inform your doctor. You may experience side effects, and some are more common than others You may experience side effects, and some are more common than others Sildenafil may cause side effects which include dizziness and altered vision. You should be aware of your personal reaction to sildenafil before you drive or operate heavy machinery whilst taking it. Sildenafil may cause side effects which include dizziness and altered vision. you experience any sudden decrease or loss of vision; you experience any sudden decrease or loss of vision; you experience any allergic reaction, such as wheeze, breathing difficulties, or swelling around the eyes or airways; you experience any allergic reaction, such as wheeze, breathing difficulties, or swelling around the eyes or airways; (If you are on nitrate medications for chest pain, do not take them.) (If you are on nitrate medications for chest pain, do not take them.) Severe side effects are rare, but they do happen.

What are the most common side effects of sildenafil?

If you do experience any of the above severe side effects, you should seek urgent medical attention. Handled correctly, sildenafil citrate is a generally safe and effective way to treat erectile dysfunction. But you should always read the Patient Information Leaflet before taking it. To find out more, book a consultation with one of our clinicians. Although Viagra® is effective for most guys with erectile dysfunction (ED), it’s important to make sure you’re taking the right dose. For most men, your first dose will be 50 mg, taken as needed up to once a day. However, older people or those who have kidney or liver issues might start at a lower dose Although your healthcare provider will provide the ultimate answer, we can address some general questions about this FDA-approved medication like how it works, typical dosages, and factors that influence optimal dosage.

• Store sildenafil citrate tablets in a cool, dry place away from children.
• Sildenafil is available by prescription only in most countries.
• 200mg doses are generally for severe cases or under medical supervision.
• The medication is not a cure for erectile dysfunction but helps manage symptoms.
• Common brands include Viagra and generic sildenafil tablets.
• Be aware of possible allergic reactions like rash and swelling.

Viagra is a medication for treating erectile dysfunction famously called “the little blue pill.” The active ingredient in Viagra is called sildenafil citrate. It’s available as a brand-name drug under the name Viagra and as a generic medication called sildenafil, which is usually available at a much lower cost per tablet. Viagra is part of a class of drugs called phosphodiesterase type 5 or PDE5 inhibitors. In essence, they work by relaxing the blood vessels in your penis to improve blood flow. Erections are all about healthy blood flow. When you’re aroused, your nervous system sends signals to relax the blood vessels that supply the penis.

This causes the corpora cavernosa (the erectile tissues inside your penis) to expand as blood flows in. By keeping the blood vessels dilated, Viagra makes this process easier. Viagra comes as an oral tablet and is available in three doses: This is the lowest dose of Viagra. It’s usually prescribed to men with mild erectile dysfunction who only need a little bit of help getting and staying hard or to men who are experiencing bothersome side effects at higher doses.

This is the lowest dose of Viagra.

What other information should I know?

Do not let anyone else take your medication. Ask your pharmacist any questions you have about refilling your prescription. Keep a written list of all of the prescription and nonprescription (over-the-counter) medicines, vitamins, minerals, and dietary supplements you are taking. Bring this list with you each time you visit a doctor or if you are admitted to the hospital. You should carry the list with you in case of emergencies.

How should I store sildenafil?

A complete guide to L-arginine for erections Let's delve into the science behind L-arginine’s ability to improve erectile function - and examine just how effective it is. To ensure you’re getting the best results from sildenafil, you should make sure that you’re using it correctly and safely. Below we have detailed the answers to some of the most commonly asked questions about taking sildenafil correctly. If you want to find out about the possible side effects of sildenafil, you can find a separate article about that here. Sildenafil is a medication used to treat erectile dysfunction which is effective and generally well-tolerated.

Dosage adjustments

There are a few potential side effects to be aware of, including headaches, nausea, and dizziness. These are fairly uncommon, but if you are struggling with them you should speak to your clinician. But like any other medication, it needs to be taken exactly as your doctor or pharmacist has instructed. Sildenafil works by allowing your arteries to relax and open, by making more of a chemical called cGMP available. Increasing blood flow through the arteries in the penis means improved erectile function. This is the usual starting dose of Viagra for most men.

Your healthcare provider may start you on this dose if you have ED and want to try medication. It’s usually prescribed to men with severe ED or men who don’t notice improvements at 50mg. Sildenafil, the active ingredient in Viagra, is available in the same doses. Additionally, sildenafil is available in a 20mg dose as either brand-name Revatio® or its generic. Revatio is a medication used to treat pulmonary arterial hypertension (PAH). By taking multiple tablets of Revatio or its generic form for ED, it’s possible to approximate the doses of Viagra.

Other uses for this medicine

If you are taking sildenafil (Liqrev, Revatio) for PAH, do not stop taking your medication until you talk to your doctor. Call your doctor if you have any unusual problems while you are taking this medication. If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting program online ( or by phone (1-800-332-1088). Keep this medication in the container it came in, tightly closed, and out of reach of children. Store the tablets at room temperature and away from excess heat and moisture (not in the bathroom).

How does sildenafil work (mechanism of action)?

Store the suspension at room temperature or in a refrigerator, but do not freeze it. Dispose of any unused suspension after 60 days. Keep all medication out of sight and reach of children as many containers are not child-resistant. Place the medication in a safe location – one that is up and away and out of their sight and reach. Dispose of unneeded medications in a way so that pets, children, and other people cannot take them.

Missed Dose

Do not flush this medication down the toilet. Talk to your pharmacist about take-back programs in your community. Visit the FDA's Safe Disposal of Medicines website for more information. In case of overdose, call the poison control helpline at 1-800-222-1222. Information is also available online at If the victim has collapsed, had a seizure, has trouble breathing, or can't be awakened, immediately call emergency services at 911. But you should only do this if it’s what a healthcare provider prescribes. What Viagra Dosage Is Best For You? Finding the perfect Viagra dose can be a matter of trial and error.

• Sildenafil can sometimes interact with certain antidepressants and antibiotics.
• Use the lowest effective dose to minimize risks and side effects.
• Alcohol can amplify unwanted effects like dizziness or hypotension.
• Regular medical checkups are advisable during long-term use.
• Ensure you only purchase from licensed pharmacies to avoid fakes.
• The medication should not be used with other ED treatments simultaneously.