Anterior Ischemic Optic Neuropathy 'Possible' Side Effect of Interferon

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Anterior Ischemic Optic Neuropathy 'Possible' Side Effect of Interferon

NEW YORK (Reuters Health) Aug 04 - Interferon alpha therapy might rarely be linked with anterior ischemic optic neuropathy (AION), a new case series suggests.

"It's probably a real side effect but I can only classify it as 'possible' right now," said Dr. Rick W. Fraunfelder of the Oregon Health and Science University Casey Eye Institute, who co-wrote the article with his father Dr. Frederick T. Fraunfelder.

"If somebody has vision loss while they are taking interferon," he advised, "consider stopping interferon if it's feasible."

The younger Dr. Fraunfelder, who directs the National Registry of Drug-Induced Ocular Side Effects, said he had found 36 cases of AION. Twenty-seven came from the literature, while the rest came from the registry of spontaneous reports.

Interferon is first-line treatment for hepatitis B and C, and is also used in cancers such as melanoma and hairy cell leukemia. Dr. Fraunfelder estimated it has been used in millions of people worldwide.

"We already know that it causes irritative conjunctivitis," he said. "The new thing is that it might also cause AION, which is basically a stroke of the eye."

The possible link to AION was noted as far back as 1995, but nobody paid much attention to it, according to Dr. Fraunfelder, and the Physicians' Desk Reference doesn't mention it.

The cases involved 10 women and 26 men, with an average age of 55. When they developed AION, they had been taking interferon alpha for 4.5 months on average, in both low and high doses and both the pegylated and non-pegylated forms.

Two-thirds of the cases of AION were bilateral, and half had some form of permanent vision loss, the authors report in their article, published online July 14th in Ophthalmology.

Based on the case series, the researchers determined that the link between interferon alpha and AION was 'possibly' causal, according to World Health Organization criteria.

It is not clear how interferon would cause AION, and the frequency of the potential side effect is unknown.

"If it does occur, it's very rare," said Dr. Fraunfelder, adding that patients on interferon who experience vision problems should be referred to an ophthalmologist.

SOURCE: http://link.reuters.com/xyb43n

Ophthalmology 2010.

http://www.medscape.com/viewarticle/726364