Absence of bilateral vision loss from amiodarone: a randomized trial

Area of Science:

• Ophthalmology
• Cardiology
• Pharmacology

Background:

• Amiodarone's association with toxic optic neuropathy is primarily based on case reports.
• Previous frequency estimates lacked dose and duration data, overestimating risk compared to other optic neuropathies.
• The study aimed to clarify the incidence of amiodarone-induced vision loss.

Purpose of the Study:

• To determine the incidence of bilateral vision loss due to amiodarone.
• To establish the relationship between amiodarone dosage, treatment duration, and the onset of vision loss.
• To assess amiodarone's safety profile regarding optic neuropathy as a secondary endpoint.

Main Methods:

• Prospective, double-masked, randomized trial comparing amiodarone (n=837) to placebo (n=832).
• Body weight-determined amiodarone dosing.
• Minimum follow-up of 27 months (median 45.5 months in survivors), with bilateral vision loss as the study endpoint.

Main Results:

• No participants were removed from the study due to bilateral vision loss.
• Maximum possible annual incidence rates of vision loss were low, even at higher doses (>4.0 mg/kg) and durations (>60 months).
• The overall maximum possible annual incidence rate in all amiodarone subjects was 0.13%.

Conclusions:

• Bilateral vision loss from amiodarone toxic optic neuropathy is infrequent at commonly used clinical doses.
• The study suggests that amiodarone-induced optic neuropathy is rare, challenging previous assumptions based on case reports.