Medically reviewed by Notre équipe éditoriale
Written by Anne-Sophie Laignel
Last updated 1/22/2025 - 5 min read
Cialis 20 mg works by inhibiting the enzyme phosphodiesterase type 5 (PDE5), which is responsible for the breakdown of cyclic guanosine monophosphate (cGMP). The latter is a key molecule in the physiological process of erection. When a man is sexually stimulated, the body releases nitric oxide, which increases the production of cGMP in the penis. cGMP causes the smooth muscles in the penile arteries to relax, allowing blood to flow more easily, leading to an erection.
However, PDE5 reduces the amount of cGMP in the penis, thus preventing a sustained erection. By inhibiting this enzyme, Cialis helps to maintain higher levels of cGMP in the penis, thereby facilitating an erection when sexual arousal occurs. Like other PDE5 inhibitors, Cialis does not cause an erection automatically, but enhances the body's response to sexual stimulation.
Cialis 20 mg is often prescribed to men who have occasional or less frequent sexual intercourse, as this dosage is more concentrated and can last longer. It is generally recommended to take Cialis 20 mg about 30 to 60 minutes before planned sexual activity. The medication starts to work quickly, and the maximum effect is reached approximately 2 hours after ingestion.
This medication is not intended for daily use, unlike Cialis 5 mg, which can be taken every day to maintain a constant erectile function. Cialis 20 mg is taken as needed, meaning it is only used when the man anticipates sexual activity. It can be taken with or without food, although absorption may be slightly slower if the medication is taken after a meal high in fat.
It is important to adhere to the prescribed dosage, as taking more than 20 mg at once does not enhance the medication's effect and increases the risk of side effects. If in doubt about the dosage, it is essential to consult a healthcare professional.
One of the main advantages of Cialis 20 mg compared to other PDE5 inhibitors, such as Viagra, is its extended duration of action. After a single dose, Cialis remains effective for about 24 to 36 hours. This allows men great flexibility, as the erection does not depend on as narrow a time window as that of other medications.
The extended duration of action makes Cialis a drug of choice for men who prefer a degree of spontaneity in their sexual encounters, as it allows for an erection to occur at any time within this 24 to 36-hour period, under the influence of sexual stimulation. This 'window of effectiveness' is much longer than that of other erectile dysfunction medications, which often have effects limited to just a few hours.
However, it is important to note that although the medication is active for an extended period, this does not mean that an erection lasts for this entire time. An erection will only occur when the man is sexually stimulated, and it will subside once the excitement is over. This reduces the risk of priapism (prolonged and painful erection), a side effect that can occur with some other erectile dysfunction medications.
Cialis 20 mg is generally well tolerated, but like any medication, it can cause side effects. The most common adverse effects are similar to those observed with other PDE5 inhibitors and include headaches, hot flashes, muscle pain, and digestive issues such as indigestion. These side effects are usually temporary and disappear after a few hours.
More serious side effects, although rare, can occur. This includes severe allergic reactions, chest pain, dizziness, visual disturbances, or prolonged pain in muscles and joints. In very rare cases, Cialis can cause a prolonged erection (priapism), which requires immediate medical attention.
Cialis should not be taken with medications containing nitrates, often prescribed for chest pain, as this combination can cause a significant drop in blood pressure, which can be dangerous. Additionally, Cialis can interact with other medications, including certain blood pressure drugs, so it is essential to consult a doctor before starting treatment to ensure it is safe.
Cialis 20 mg is an effective treatment for erectile dysfunction, offering extended action from 24 to 36 hours. This allows men greater flexibility and more freedom in planning their sexual activities. By inhibiting the PDE5 enzyme, it improves blood flow to the penis and thus facilitates an erection in response to sexual stimulation. As with any medication, it is important to use it under the supervision of a healthcare professional to avoid the risk of side effects and ensure optimal effectiveness.
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