Viagra 25 mg works by inhibiting the PDE5 enzyme, allowing for improved blood flow and facilitating an erection in response to sexual stimulation. It is taken before sexual activity and is effective for 4 to 6 hours. This medication can cause mild side effects, but it is essential to consult a doctor before using it to avoid potential risks.

Understand how Viagra 25 mg works!

author-image

Medically reviewed by Notre équipe éditoriale

Written by Anne-Sophie Laignel

Last updated 1/22/2025 - 5 min read

The mechanism of action of Viagra 25 mg

Viagra 25 mg works by inhibiting the enzyme PDE5 (phosphodiesterase type 5), which is responsible for breaking down cyclic guanosine monophosphate (cGMP) in the penis. cGMP plays a crucial role in the erection process. During sexual arousal, nitric oxide is released, stimulating the production of cGMP in the cells of the penis. This process causes the relaxation of smooth muscles in the arteries of the penis, allowing blood to flow more freely into the area, thereby leading to an erection.

However, the enzyme PDE5 reduces the amount of cGMP in the penis, which decreases the body's ability to maintain an erection. By inhibiting PDE5, Viagra helps to maintain higher levels of cGMP in the penis, thereby improving blood flow and facilitating the achievement and maintenance of an erection when the man is sexually stimulated.

It is important to note that Viagra does not automatically induce an erection. The medication only works when sexual arousal is present, and it does not produce erections without stimulation.

Prescription for Viagra
Getting a prescription for Viagra
cta-image

The dosage and frequency of administration of Viagra 25 mg

Viagra 25 mg is generally prescribed to men who have mild to moderate erectile dysfunction or who are at risk of side effects due to increased sensitivity to medication. This dosage allows for the assessment of the drug's effectiveness while minimizing the risk of adverse effects.

Viagra 25 mg should be taken about 30 to 60 minutes before sexual intercourse. It starts to work quickly, and its maximum effect is reached after about 1 to 2 hours. The medication can be taken with or without food, but it is important to note that the absorption of Viagra can be delayed if it is taken after a meal high in fat.

Viagra 25 mg should not be taken more than once a day. If the effect of the medication is not sufficient, the doctor may adjust the dose, increasing the amount to 50 mg or 100 mg, depending on the patient's needs and their response to the treatment.

The duration of effect of 25 mg Viagra

The duration of the effect of Viagra 25 mg is usually about 4 to 6 hours. This means that a man can achieve and maintain an erection during this period, under the effect of sexual stimulation. However, it is important to note that the erection will not be continuous throughout this period, but it can occur at several times during this 4 to 6-hour window.

The effects of Viagra usually begin to wear off after about 4 hours. If an erection is not achieved within this time frame or if it fades before sexual activity is completed, it may be necessary to take another dose, but this should always be done following medical advice to avoid any risk of side effects.

It is also important to note that the duration of Viagra's effect can vary from one person to another. Some may experience a longer effect, while others may find that it wears off more quickly. Individual factors, such as age, health status, other medications, and food, can influence this duration.

Possible side effects of Viagra 25 mg

Like any medication, Viagra 25 mg can cause side effects. The most common adverse effects are mild and temporary. They include:

  • Headaches: This is the most frequently reported side effect by Viagra users.
  • Hot flashes: A feeling of warmth in the face or upper body.
  • Digestive troubles: Such as heartburn or indigestion.
  • Nasal congestion: A feeling of a blocked nose is also common.
  • Vision impairment: Some individuals may experience temporary changes in color perception or slight sensitivity to light.

In rare cases, more serious side effects may occur. This can include:

  • Priapism: A prolonged and painful erection lasting more than 4 hours that requires emergency medical intervention.
  • Heart problems: Viagra can lead to adverse effects on the heart, especially in individuals with a history of heart diseases.
  • Severe vision problems: In very rare cases, vision disorders such as sudden loss of vision in one or both eyes may occur.

It is imperative to consult a doctor if any of these serious side effects occur or if mild side effects persist or become bothersome.

The contraindications and precautions to take

Viagra 25 mg should not be used by certain individuals, especially those who:

  • Take medications containing nitrates, used to treat angina pectoris, as this can lead to a dangerous drop in blood pressure.
  • Have a history of serious heart problems, uncontrolled high blood pressure, or liver or kidney diseases.
  • Are allergic to any of the components of Viagra.

Before starting a Viagra treatment, it is crucial to consult a doctor to discuss medical history and any other medications you might be taking.

Viagra 25 mg is an effective option for treating erectile dysfunction, especially in men who have a moderate response to higher doses. It works by inhibiting PDE5 and improving blood flow to the penis, thus facilitating an erection in response to sexual stimulation. With a duration of action of 4 to 6 hours, it provides a sufficient period for the completion of sexual activity. However, as with any medication, it is important to follow your doctor's recommendations to minimize the risk of side effects and ensure the effectiveness of the treatment.

Evaluate Your Erectile Function in 2 Minutes

The IIEF-5 Index is a recognized tool to assess erectile function. Answer 5 questions and discover your score and options in complete confidentiality.

IIEF-5

Over the last six months

How do you rate your confidence that you could get and keep an erection?

Very low

Low

Moderate

High

Very high

Discover more articles about men's health

main-image
Everything you need to know about Tadalafil 5 mg!
main-image
What medication should be taken to achieve an erection?
main-image
Everything You Need to Know About Sildenafil 50 mg!

They have taken control of their sexual health, join them.

I highly recommend Kano Care
I highly recommend Kano Care, who provided me with essential assistance in getting a prescription issued.
Mickael | 43 years old
Very quick and reliable
I recommend them. I contacted them, and the prescription was issued 30 minutes later. Then, straight to the pharmacy to pick it up. Thank you!
Nicolas | 25 years old
It works perfectly
You enter the information, and then a few days later, the prescription is ready at the pharmacy. I used the service twice, and both times it worked well. In my opinion, I recommend it.
Didier | 54 years old

1 sources

https://labeling.pfizer.com/ShowLabeling.aspx?id=2306