Can I start him on sildenafil (Viagra) for erectile dysfunction?

Sildenafil for Erectile Dysfunction Treatment

Sildenafil (Viagra) should be offered as first-line therapy for erectile dysfunction unless contraindicated, with an initial dose of 50mg taken approximately 1 hour before sexual activity. 1, 2

Cardiovascular Risk Assessment

Before initiating sildenafil therapy, it's essential to assess cardiovascular risk and categorize patients:

• High-risk patients (unstable/refractory angina, uncontrolled hypertension, CHF NYHA class II+, recent MI/CVA within 2 weeks, high-risk arrhythmias, hypertrophic cardiomyopathies, moderate-severe valvular disease) should not receive treatment until cardiac condition is stabilized 1, 2

• Low-risk patients (asymptomatic coronary artery disease with <3 risk factors, controlled hypertension, mild stable angina, successful coronary revascularization, uncomplicated past MI, mild valvular disease, CHF NYHA class I) may receive sildenafil 1

• Intermediate-risk patients should undergo cardiology evaluation before treatment 1, 2

Absolute Contraindications

• Concurrent use of nitrates in any form (tablets, patches, sprays, ointments) 1, 3
• Use of "poppers" (amyl nitrate/nitrite) 3

Dosing and Administration

• Initial dose: 50mg taken as needed approximately 1 hour before sexual activity 4
• Dose adjustment: Can be increased to 100mg or decreased to 25mg based on efficacy and tolerability 4
• Maximum frequency: No more than once daily 3
• Special populations: Lower starting dose (25mg) recommended for:
  • Elderly patients
  • Hepatic or renal impairment
  • Patients taking CYP3A4 inhibitors (ritonavir, saquinavir, ketoconazole, erythromycin, cimetidine) 4

Proper Medication Use Instructions

To maximize effectiveness, instruct patients to:

• Take on an empty stomach (especially sildenafil) 2
• Allow sufficient time for onset of action (30-60 minutes) 2
• Ensure adequate sexual stimulation 2
• Try medication on multiple occasions before concluding it doesn't work 2

Common Side Effects

• Headache (11%)
• Flushing
• Dyspepsia (9%)
• Nasal congestion
• Visual disturbances (color-tinge to vision, increased light sensitivity)
• Dizziness 3, 4

Monitoring and Follow-up

Regular follow-up is recommended to:

• Assess efficacy
• Monitor side effects
• Evaluate any changes in health status or medications 1, 2

Special Considerations

• Diabetes: Sildenafil has demonstrated efficacy and safety in diabetic patients with erectile dysfunction, with 56% reporting improved erections compared to 10% with placebo 5

• Visual/Hearing changes: Patients should seek immediate medical attention for sudden vision loss (possible NAION) or hearing decrease/loss 3

• Drug interactions: Exercise caution with alpha-blockers due to potential hypotension 2

• Treatment failure: If sildenafil fails after adequate trials, consider:

  • Different PDE5 inhibitor (tadalafil, vardenafil)
  • Second-line therapies (alprostadil intra-urethral suppositories, intracavernous injections)
  • Vacuum constriction devices
  • Penile prostheses 2

Sildenafil has proven to be an effective oral treatment for erectile dysfunction across various etiologies, with significant improvements in erection quality and sexual satisfaction compared to placebo 4, 6.