Which drug is associated with non-arteritic anterior ischemic optic neuropathy (NAION)?

• A. Sildenafil
• B. Digoxin
• C. Ethambutol
• D. Acetaminophen

Answer: (A)

NAION happens when blood flow to the optic nerve head is insufficient in eyes that are predisposed (often with a crowded optic disc and vascular risk factors), leading to sudden, painless vision loss. Drugs that can alter systemic blood pressure or ocular blood flow may tip the balance in someone already at risk.

Sildenafil, a PDE-5 inhibitor, has been associated with NAION. It can cause systemic vasodilation and transient drops in blood pressure, which may reduce perfusion to the optic nerve head in susceptible individuals. There are case reports and regulatory warnings noting this possible link, so among the options it stands out as the drug connected to NAION.

Digoxin isn’t linked to NAION; ethambutol can cause optic neuropathy, but that’s toxic rather than ischemic in nature; acetaminophen has no known association with NAION.