Confidence in Every Sachet
What is Sildenafil Citrate?
Sildenafil Citrate is a phosphodiesterase type 5 (PDE5) inhibitor and the active pharmaceutical ingredient (API) in medications like Viagra® and Kamagra Oral Jelly. It is primarily used to treat:
Erectile Dysfunction (ED): Enhances blood flow to the penis to facilitate and sustain erections.
Pulmonary Arterial Hypertension (PAH): Relaxes pulmonary blood vessels to reduce high blood pressure in the lungs (marketed as Revatio®).
Mechanism of Action
Sildenafil inhibits the PDE5 enzyme, which normally breaks down cyclic guanosine monophosphate (cGMP).
By blocking PDE5, cGMP levels increase, causing smooth muscle relaxation and vasodilation in the penis (for ED) or pulmonary arteries (for PAH).
Sexual stimulation is required for ED treatment, as it triggers the release of nitric oxide (NO), which initiates cGMP production.
Key Pharmacological Properties
Onset: Effects typically begin within 30–60 minutes of oral administration.
Duration: Lasts 4–6 hours, depending on metabolism, age, and health status.
Bioavailability: ~40% (oral absorption is reduced by high-fat meals).
Dosage Forms & Strengths
ED:
Tablets: 25mg, 50mg, 100mg (usual starting dose: 50mg).
Oral Jelly (e.g., Kamagra): 100mg per sachet.
PAH: 20mg tablets (taken 3x daily).
Common Side Effects
Mild: Headache, flushing, nasal congestion, indigestion, blurred vision (due to transient PDE6 inhibition in the retina).
Rare but Serious:
Priapism (prolonged, painful erection requiring urgent care).
Sudden hearing/vision loss (linked to vascular complications).
Hypotension (especially if combined with nitrates).
Contraindications
Absolute:
Concurrent use of nitrates (e.g., nitroglycerin) or riociguat (risk of life-threatening hypotension).
Severe cardiovascular disease (recent heart attack, stroke, or unstable angina).
Relative:
Liver/kidney impairment (dose adjustment required).
Anatomical penile deformities (e.g., Peyronie’s disease).
Drug Interactions
Avoid:
Nitrates, alpha-blockers, antihypertensives, and CYP3A4 inhibitors (e.g., erythromycin, grapefruit juice), which may amplify side effects.
Use with Caution:
Alcohol (increases hypotension risk).
Important Warnings
Not an aphrodisiac: Requires sexual stimulation to work.
Avoid self-prescription: Always consult a physician to rule out underlying health issues (e.g., heart disease).
Counterfeit risks: Unregulated products may contain incorrect doses or harmful additives.
Off-Label Uses
Sometimes prescribed for altitude sickness or Raynaud’s phenomenon, but evidence is limited.
