Fildena 100, which contains sildenafil citrate as its active ingredient, is primarily known for its use in treating erectile dysfunction (ED) in men by increasing blood flow to the penis during sexual stimulation. However, sildenafil citrate is also used in the treatment of pulmonary arterial hypertension (PAH), a condition characterized by high blood pressure in the arteries of the lungs.

The use of sildenafil citrate for PAH is based on its mechanism of action as a phosphodiesterase type 5 (PDE5) inhibitor. In PAH, the blood vessels in the lungs become narrowed and constricted, leading to increased resistance to blood flow. This can cause the right side of the heart to work harder to pump blood through the lungs, leading to symptoms such as shortness of breath, fatigue, and chest pain.

Sildenafil citrate works by inhibiting the enzyme PDE5, Fildena 100 is responsible for breaking down cyclic guanosine monophosphate (cGMP), a molecule that relaxes smooth muscle cells and dilates blood vessels. By inhibiting PDE5, sildenafil citrate helps to increase levels of cGMP, leading to relaxation of the smooth muscle cells in the blood vessels of the lungs and improved blood flow.

In individuals with PAH, this vasodilatory effect of sildenafil citrate can help reduce pulmonary artery pressure and improve exercise capacity, symptoms, and quality of life. It can also help delay disease progression and improve outcomes in some cases.

It's important to note that the use of sildenafil citrate for PAH is typically prescribed at higher doses than those used for treating ED. Dosage and treatment regimens for PAH should be determined by a healthcare professional experienced in managing this condition, and regular monitoring is necessary to assess treatment response and adjust therapy as needed.

While sildenafil citrate can be effective in treating PAH, it's essential to discuss the risks and benefits of treatment with a healthcare professional, as well as any potential interactions with other medications or medical conditions. Additionally, individuals with certain pre-existing cardiovascular conditions or taking nitrates should use sildenafil citrate for PAH with caution, as it can interact with these medications and cause potentially serious side effects.