Sildenafil primarily works by inhibiting phosphodiesterase type 5 (PDE5), an enzyme that breaks down cyclic guanosine monophosphate (cGMP). Increased cGMP levels relax the smooth muscles in the blood vessels of the penis, allowing increased blood flow and facilitating an erection. This mechanism is specific to the penis, preventing systemic effects.
Primary Use: Erectile Dysfunction
Sildenafil’s most common use is to treat erectile dysfunction (ED), a condition characterized by the inability to achieve or maintain an erection firm enough for satisfactory sexual intercourse. It’s important to note that Sildenafil aids in achieving an erection only when sexual stimulation is present.
Secondary Use: Pulmonary Arterial Hypertension
Beyond ED, Sildenafil also treats pulmonary arterial hypertension (PAH), a condition characterized by high blood pressure in the arteries leading to the lungs. By relaxing blood vessels, it improves blood flow and reduces strain on the heart. This application requires careful monitoring and dosage adjustment by a physician.
Important Considerations and Interactions
Before using Sildenafil, consult your doctor. Certain medical conditions, like heart problems or low blood pressure, may necessitate caution. Furthermore, interactions exist with certain medications, particularly nitrates which can lead to dangerously low blood pressure. Always disclose all medications you are taking to your physician.
| Nitrates | Significant risk of hypotension | Avoid concurrent use. |
| Alpha-blockers (e. g., Terazosin) | Increased risk of hypotension | Physician monitoring recommended; dosage adjustments may be necessary. |
| CYP3A4 inhibitors (e. g., ketoconazole, ritonavir) | Increased Sildenafil levels | Physician consultation crucial for dosage adjustment. |
Dosage and Administration
Dosage varies depending on the condition and individual patient factors. Always follow your doctor’s instructions. Typical dosages range from 25mg to 100mg for ED, taken as needed, and vary significantly for PAH.
