What is the likelihood of developing optic neuritis from sildenafil (Viagra) use in a 67-year-old male?

Risk of Optic Neuritis from Sildenafil Use in a 67-Year-Old Male

The risk of developing optic neuritis specifically from sildenafil use in a 67-year-old male is low, but there is an increased risk for "possible NAION" (which includes optic neuritis) with a relative risk of 1.34 [CI, 1.17 to 1.55] and an absolute risk of 2.4 cases per 10,000 men per year. 1

Understanding the Risk

Evidence on Sildenafil and Optic Nerve Problems

• Very-low-quality evidence from a large study of 4 million veterans aged 50 years or older showed that PDE-5 inhibitors:

  • Were not associated with an increased risk for definitive NAION (relative risk 1.02 [95% CI, 0.92 to 1.12])
  • Were associated with an increased risk for "possible NAION" which includes papillitis and optic neuritis (relative risk 1.34 [CI, 1.17 to 1.55]) 2

• The absolute risk of possible NAION (including optic neuritis) is approximately 2.4 cases per 10,000 men per year 2

• Another study estimated an incidence of 2.8 cases of NAION per 100,000 patient-years of sildenafil exposure, which is similar to the general population rate (2.52-11.8 cases per 100,000 men aged ≥50 years) 3

Risk Factors That May Increase Concern

The risk may be higher in patients with:

• Pre-existing vascular risk factors (particularly diabetes) 4
• History of NAION in one eye (strong contraindication) 1
• Crowded optic disc anatomy (small cup-to-disc ratio) 5
• Concurrent use of medications that may affect ocular blood flow

Clinical Presentation of Sildenafil-Associated Optic Nerve Problems

If optic neuritis or NAION develops, patients typically present with:

• Sudden, painless vision loss (usually unilateral but can be bilateral) 4, 5
• Visual field defects (commonly inferior altitudinal) 5
• Decreased visual acuity
• Optic disc edema on fundoscopic examination

Important Considerations for a 67-Year-Old Male

1. Timing of symptoms: Visual symptoms can occur even hours after medication intake 1

2. Dosing concerns: The risk may increase with:

   • Higher doses
   • Frequent use
   • Recreational rather than prescribed use 6

3. Monitoring recommendations:

   • Baseline ophthalmologic examination before starting therapy
   • Regular follow-up examinations
   • Immediate medical attention for any visual disturbances 1

Management Recommendations

1. Pre-treatment evaluation:

   • Assess for pre-existing optic nerve disorders
   • Document baseline visual acuity and visual fields
   • Evaluate for vascular risk factors (diabetes, hypertension)

2. Patient education:

   • Advise about potential visual side effects
   • Instruct to seek immediate medical attention for any visual changes
   • Explain that symptoms may occur even hours after taking the medication 1

3. Contraindications:

   • History of NAION in either eye
   • Concurrent use of nitrates in any form 2, 1

4. Monitoring:

   • Periodic ophthalmologic follow-up
   • Prompt evaluation of any visual symptoms

Conclusion

While the absolute risk of developing optic neuritis from sildenafil use is low in a 67-year-old male, the patient should be informed about the potential risk and monitored appropriately. The benefits of sildenafil for erectile dysfunction should be weighed against this small but significant risk, particularly in patients with pre-existing vascular risk factors.