Does voriconazole cause visual disturbances?

Does Voriconazole Cause Visual Disturbances?

Yes, voriconazole commonly causes transient visual disturbances in approximately 21-30% of patients, including photophobia, blurred vision, changes in color perception (chromatopsia), and photopsia. 1, 2, 3

Nature and Frequency of Visual Disturbances

Visual disturbances are one of the most characteristic adverse effects of voriconazole therapy:

• Approximately 21% of patients in therapeutic trials experienced abnormal vision, color vision changes, and/or photophobia 3
• Other sources report visual disturbances occurring in approximately 30% of patients receiving voriconazole 1, 4
• These effects are dose-related and may be associated with higher plasma concentrations and/or doses 3

Specific Visual Symptoms

The visual disturbances manifest in several distinct ways:

• Photopsia (seeing flashes of light) occurs in 2.2% of patients 3
• Photophobia (light sensitivity) occurs in 2.2-2.5% of patients 3
• Chromatopsia (altered color perception) occurs in 1.0-1.2% of patients 3
• Blurred vision is commonly reported 1
• Visual hallucinations have been documented in pediatric cases 5

Mechanism and Reversibility

The mechanism underlying these visual disturbances involves retinal effects:

• The site of action is most likely within the retina 3
• Studies in healthy subjects show voriconazole causes decreased electroretinogram (ERG) waveform amplitude, decreased visual field, and altered color perception 3
• These effects are transient and reversible - ERG, visual fields, and color perception returned to normal 14 days after discontinuation of dosing 3
• The visual disturbances are noted early in administration and continue through the course of treatment 3

Clinical Significance

While common, these visual disturbances are generally non-sight-threatening:

• The visual effects are described as "transient" and "non-sight-threatening" 4
• However, more serious macular toxicity and blind spot enlargement have been reported in rare cases 6
• Visual disturbances occurred significantly more frequently with voriconazole than with amphotericin B in comparative trials (p < 0.001) 7

Management Considerations

When visual disturbances occur during voriconazole therapy:

• Measurement of serum voriconazole levels is useful to evaluate for potential toxicity, as toxicity is more common with higher drug levels 2
• Dose reduction may be attempted first, though this was not effective in preventing visual side effects in at least one documented case 6
• If symptoms persist or are severe, discontinuation and switching to an alternative antifungal (such as itraconazole) within the same drug family may be necessary 6
• Visual symptoms typically resolve after discontinuation of voriconazole 5

Common Pitfall

A critical pitfall is failing to counsel patients about expected visual disturbances before initiating therapy. Since these effects occur in up to 30% of patients and begin early in treatment, patients should be warned that transient visual changes are common, generally reversible, and do not typically require drug discontinuation unless severe 1, 3. This prevents unnecessary alarm and ophthalmologic investigations for what is usually a benign, self-limited adverse effect 5.