Sildenafil Tablets

Mechanism

Sildenafil inhibits phosphodiesterase type 5 (PDE5), leading to increased levels of cyclic guanosine monophosphate (cGMP). This results in smooth muscle relaxation and increased blood flow to the penile tissues, facilitating erection.

Pharmacokinetics

• Absorption: Sildenafil is rapidly absorbed after oral administration, with peak plasma concentrations reached within 30–120 minutes (median ~60 minutes).
• Bioavailability: Approximately 40% due to first-pass metabolism.
• Distribution: Volume of distribution ~105 L; plasma protein binding ~96%.
• Metabolism: Extensively metabolized in the liver, primarily via CYP3A4 (major route) and CYP2C9 (minor route).
• Elimination: Excreted mainly as metabolites in feces (~80%) and urine (~13%).
• Half-life: Terminal elimination half-life is approximately 3–5 hours.

Side Effects

• Headache
• Flushing
• Dizziness
• Indigestion
• Visual disturbances

Contraindication

• Use with nitrates
• Severe cardiovascular disorders
• Hypersensitivity to sildenafil

Interaction

• Nitrates: Severe hypotension risk
• CYP3A4 inhibitors: Increase sildenafil levels
• Alcohol: May enhance side effects

Warning and Precautions

This has been prescribed for the patient's specific condition. It may be dangerous to any other person.

• Use under medical supervision
• Caution in cardiovascular disease
• Avoid overdose
• Not recommended with nitrates

Dosage

As directed by the Physician.