Maximum Daily Dose of Viagra (Sildenafil)
The maximum daily dose of Viagra (sildenafil) for erectile dysfunction is 100 mg once daily, taken approximately one hour before sexual activity. 1, 2, 3
Dosing Guidelines for Erectile Dysfunction
Standard Dosing Regimen
- Starting dose: 50 mg taken approximately one hour before sexual activity 1
- Dose range: 25-100 mg based on efficacy and tolerability 1, 3
- Maximum dose: 100 mg once daily 1, 3
- Frequency: Not more than once daily 4, 3, 5
Dose Adjustments
- If 50 mg is insufficient: May increase to 100 mg for improved efficacy 1
- Elderly patients or those with hepatic/renal impairment: Consider starting with 25 mg 3
- Patients on CYP3A4 inhibitors (ritonavir, saquinavir, ketoconazole, erythromycin, cimetidine): Use lower doses such as 25 mg 3, 6
Efficacy by Dose
- Approximately 69% of men report improved erections with sildenafil versus 35.5% with placebo 1, 7
- Dose-related improvements occur: 50 mg shows better efficacy than 25 mg, though 100 mg versus 50 mg shows less additional benefit 1, 7
- In titrated-dose trials, the most commonly effective doses were 50 or 100 mg 3
Important Clinical Caveats
Contraindications
- Absolute contraindication: Concurrent use with nitrates or nitric oxide donors due to risk of severe hypotension 6
- This combination can cause major drops in blood pressure and is potentially life-threatening 6
Cardiovascular Considerations
- Sildenafil causes modest, transient reductions in blood pressure at recommended doses (25-100 mg) 6
- Patients with known or suspected coronary artery disease may benefit from exercise testing before resuming sexual activity with sildenafil 6
Common Side Effects
- Headache, flushing, dyspepsia, nasal congestion, and abnormal vision are the most common adverse events 4, 3
- These are typically transient and mild to moderate in severity 4, 3
Context: Pulmonary Hypertension Dosing (Different Indication)
For completeness, sildenafil is also FDA-approved for pulmonary arterial hypertension at a completely different dosing regimen: 20 mg three times daily (total 60 mg/day), with doses administered 4-6 hours apart 2. This is NOT the erectile dysfunction indication and uses a different total daily dose and frequency.