Sildenafil (Viagra) and Tadalafil (Cialis): Treating Erectile Dysfunction.
Gui í a de Salud Masculina
Sildenafil (sildenafil) and Tadalafil (tadalafil) are both drugs used to treat male erectile dysfunction (ED). Here are some of their characteristics:
I. the mechanism of action
Identical point
Both of them belong to type 5 phosphodiesterase (PDE5) inhibitors. The physiological mechanism of penile erection involves the release of nitric oxide (NO) in the corpus cavernosum during sexual stimulation. NO activates guanosine cyclase and increases the synthesis of cyclic guanosine monophosphate (cGMP). CGMP promotes the relaxation of corpus cavernosum smooth muscle and blood flow into the penile cavernous sinus, resulting in penile erection, while PDE5 can decompose cGMP and cause penile cavernous smooth muscle contraction. Penis weakness, Sildenafil and Tadalafil enhance erectile function by inhibiting PDE5 and reducing the degradation of cGMP.
Differences
Action time
SildenafilThe action time is relatively short, and its short-term effect may be more suitable for those patients who occasionally have sexual needs. Under the conventional dose, its effective time is about 4-5 hours.
TadalafilIt is known as a long-acting PDE5 inhibitor, and its effective time can be as long as 36 hours, which makes patients have a longer "effective window" after taking medicine, can choose their life more freely, and reduce the time pressure between sex life and medication time.
II. Matters needing attention in drug metabolism and use
Identical point
Dietary influenceBoth should avoid a high-fat diet, as a high-fat diet may affect the rate of absorption of drugs, thus delaying the time for drugs to take effect.
Interaction with other drugsBoth of them have serious interaction with organic nitrate drugs (such as nitroglycerin) and it is forbidden to use them at the same time, because their combination with organic nitrate drugs can lead to severe hypotension and life-threatening.
ContraindicationIt is prohibited for patients who are allergic to drug ingredients, as well as women and children (not used for the treatment of child-related diseases).
Differences
Metabolic pathway
SildenafilIt is mainly metabolized by cytochrome P450 3A4 (CYP3A4) enzymes in the liver, but also partly by CYP2C9 metabolism. When combined with CYP3A4 inhibitors (such as ketoconazole, itraconazole and other antifungal agents), the blood concentration of Sildenafil may increase, increasing the risk of adverse reactions, while when combined with CYP3A4 inducers (such as rifampicin), the blood concentration may decrease, affecting the efficacy.
TadalafilIt is mainly metabolized by CYP3A4. Similarly, there is a similar change in blood concentration when used with CYP3A4 inhibitors or inducers, but due to the long-term effect of Tadalafil, this drug interaction may last for a relatively long time in vivo.
Patients should choose to use Sildenafil or Tadalafil under the guidance of their doctor, who will determine the most appropriate treatment according to the patient's specific conditions (such as age, underlying diseases, frequency of sex, etc.).