Sildenafil citrate

Sildenafil is the generic form of the brand Viagra®. Both medications work similarly in the body. Viagra® is a type of medication that is used to treat erectile dysfunction and is known as a PDE5 inhibitor. It comes in 25mg, 50mg and 100mg doses and is taken as-needed.


Disclaimer: The information provided on this page is not a substitute for professional medical advice, diagnosis, or treatment. If you have any questions or concerns about your health, please talk to a doctor.


What is sildenafil citrate?

Sildenafil citrate is the chemical name of the active ingredient in Viagra®. When sildenafil is sold in 25, 50, or 100 mg dosages, it’s called Viagra or it is the generic for Viagra.

The One Health healthcare professionals are able to prescribe appropriate dosages of sildenafil citrate tablets for ED to match your medical circumstances. 

How should I take sildenafil?

Sildenafil should be taken 30–60 minutes before sex. It can remain active in your body for upto 8 hours.

Dietary fat can decrease and delay the absorption, which can lower sildenafil’s effectiveness. It is advised to take it prior to eating.

How long does sildenafil take to work?

Sildenafil is a short acting medication with a rapid onset.

It should be taken 30–60 minutes before sex, and it reaches peak blood levels in 60 minutes on average. Fat in a meal can delay the effects of sildenafil and also decrease the amount that is absorbed. Remember that sildenafil will not give you a spontaneous erection without sexual stimulation.

How long does sildenafil last?

Sildenafil is a short acting drug with an average half-life of 4–5 hours, which means that half the medicine is gone from the body after 4–5 hours in healthy people. The time that it takes to eliminate sildenafil may be prolonged in older people and people with liver or kidney disease and the drug may work longer in these people.

Can sildenafil have permanent effects?

Sildenafil does not have permanent effects on the body once it is broken down. It is only effective for as long as it is in the body. Sildenafil does not have permanent effects on the body once it is broken down. It is only effective for as long as it is in the body.

As you age, it is normal to see erectile function decrease. As a result, you may need more medication to see the same results. In some cases, erectile function may also worsen due to progression of the underlying disease that is causing ED (e.g., diabetes, vascular disease).

Sildenafil does not diminish in efficacy over time (i.e., you don’t need more because your body gets “used to it”).

What should I tell my doctor?

Tell your doctor or nurse practitioner if you have any problems with your heart, liver, kidneys, vision disorders, bleeding disorders, or penile deformities. Tell your doctor or nurse practitioner about all prescription medications, over the counter medications, and dietary supplements you are taking. For more safety information, please see the important safety information below.

Common side effects of sildenafil

In order to understand how sildenafil works to treat ED, it’s important to first understand the basics of how erections work. Erotic stimulation (by physical touch, erotic thoughts, smells, etc.) causes the local tissues to release nitric oxide (NO), which increases the amount of a chemical called cyclic guanosine monophosphate (cGMP). cGMP causes the muscles on the sides of the penis, the corpora cavernosa, to relax allowing blood to rush into the penis. At the same time veins that drain blood from the penis get compressed causing the increased blood to be trapped in the penis causing an erection. An enzyme called phosphodiesterase-5 breaks down cGMP leading the penis to return to its flaccid state. PDE5i, like sildenafil, block this enzyme leading to higher levels of cGMP and improving the ability to obtain and maintain an erection.


What happens if I overdose?

Taking more than the recommended amount of sildenafil citrate greatly increases your risk of side effects, including severe ones that can be dangerous, such as severe low blood pressure or an erection that won’t go away even after 4 or more hours (priapism). Never take more than the amount prescribed to you by your doctor or nurse practitioner. If you have any severe side effects after taking more than the recommended amount, or even after taking the amount of medicine prescribed to you, seek out emergency medical attention immediately.

Is buying sildenafil online safe?

Buying medication online can have risks when the source is not reputable. One study showed that 77% of Viagra sold online was counterfeit. Counterfeit PDE5i can have variable amounts of the active drug ranging from 0%–200+% of the drug. In cases where the active ingredient is present in lower amounts than expected, this can mean lack of effectiveness even though the same dose of active drug may work well in a given individual. In cases where much more active drug than listed is included, there is a higher potential for side effects, including dangerous ones like extremely low blood pressure or an erection that won’t go away even after 4 or more hours (priapism). It is also common for counterfeit drugs to contain harmful ingredients like talcum powder, commercial paint, and printer ink.

With One Health, you can always be sure you are getting genuine medication with active ingredients in the correct amount without harmful additives. One Health drugs are manufactured by pharmaceutical companies that are regulated by the FDA. In fact you will likely find many of the same manufacturers we use in your local pharmacy. With One Health, you never need to worry about what’s actually in the pills you are taking.

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