Viagra (Sildenafil) Dosage: How to Take It Correctly

Proper use maximizes efficacy and minimizes side effects.

Standard Dosing

• Starting dose: 50 mg as needed, ~1 hour before sexual activity.
• Range: 25 mg to 100 mg (max once daily).
• Adjustment: Based on efficacy/tolerability.

Administration Tips

• With water: Full glass aids swallowing and absorption.
• Empty stomach or light meal: High-fat meal delays Tmax by ~60 min, reduces Cmax ~29%.
• Avoid alcohol: ↑ risk of hypotension, dizziness, headache; impairs erection.
• No grapefruit/grapefruit juice: Inhibits CYP3A4 → ↑ sildenafil levels.

Special Populations

• ≥65 years: Start 25 mg.
• Hepatic impairment (Child-Pugh B/C): Start 25 mg.
• Severe renal impairment (CrCl <30): Start 25 mg.
• On CYP3A4 inhibitors (ketoconazole, ritonavir, clarithromycin): Max 25 mg/48h.
• On alpha-blockers: Stabilize on alpha-blocker first; start sildenafil 25 mg; separate dosing by ≥4h.

Contraindications

• Nitrates (any form), riociguat.
• Recent MI/stroke (<6 months), unstable angina, severe HF.
• Hereditary retinal disorders (retinitis pigmentosa).
• Known hypersensitivity.

If It Doesn't Work

• Ensure sexual stimulation (drug facilitates, doesn't cause erection).
• Try higher dose (if not at max).
• Try different PDE5 inhibitor (tadalafil, vardenafil, avanafil).
• Evaluate for testosterone deficiency, vascular disease, psychogenic factors.

Follow your prescriber's instructions precisely.