Sildenafil, the active substance of brand Viagra, is the medication is meant to treat erectile dysfunction (ED) of any origin (even antidepressant-induced sexual disorder) in men over 18 years old.
Sildenafil is cGMP (Cyclic guanosine monophosphate)-specific phosphodiesterase type 5 (PDE5) inhibitor. The cGMP enzyme controls penile blood flow, and Sildenafil causes degradation of PDE5. Put it simply, Sildenafil refines penile blood supply. No wonder that originally Viagra was used to treat cardiovascular diseases, including pulmonary arterial hypertension. In the course of numerous researches the medicine proved to cure sexual frustration – an inability to achieve or/and sustain satisfactory erection to perform a full intercourse.
Breakthrough action of Sildenafil
Sildenafil prevents degradation of cGMP by PDE5 in the cavernous body of a male organ. Nitrogen oxide (NO) in penile cavernous bodies binds to receptors of guanylate cyclase, what leads to enhanced levels of cGMP, causing relaxation of smooth muscle (vasodilatation or expansion of blood vessels) of intimate cushions in penile helicine arteries.
This vasodilatation provokes stronger blood inflow into spongy tissues of the phallus, what results in rigidness of penis. In other words, Sildenafil acts like a selective inhibitor of PDE5, an enzyme responsible for degradation of cyclic guanosine monophosphate in penile cavernous bodies.Without natural sexual excitement Sildenafil does not cause erection as we have just determined that erection is generated by activation of the NO/cGMP system.
By the way, Sildenafil is not only used by ED sufferers, but by professional sportsmen as well since the medication expands blood vessels, it helps athletes to achieve muscle definition and increase endurance during trainings and improve recovery after hard exercises.
Notably that Viagra based medications are popular even with those men who are not diagnosed with erectile dysfunction. As the active agent boosts blood flow into the male organ, it increases sensibility (libido), prolongs sexual performance and sharpens orgasm. That is why Sildenafil is good for recreational use too but at a reduced dose of 50 mg.
What side effects can Sildenafil cause?
If a man has no contradictions and does not exceed the recommended dose, side effects caused by Sildenafil are uncommon. Among them are:
- Dizziness and headache;
- Flushing and hot flush;
- Nausea;
- Visual disturbance;
- Tachycardia or hypertension.
Since Sildenafil potentiates the hypotensive effect of organic nitrates, the patients who take nitric oxide donors must not combine their treatment with Sildenafil based drugs.
