Tuesday, August 21, 2012

Plaquenil and Retinal Toxicity

There are many medicines that have side effects that can affect the eye. Most of them are minor and little more than a bit of an inconvenience. Some of them can cause vision loss, and for those it is sometimes necessary to visit an eye doctor to rule out and problems.

One of these medicines is Plaquenil, also known by its chemical name hydroxychloroquine. Plaquenil is a medicine which was developed from chloroquine, one of the original medicines used to treat malaria. Doctors discovered that a beneficial side effect of these medicines was a decrease in joint inflammation and pain in people who suffer from rheumatoid arthritis and other inflammatory diseases. Unfortunately there is also a risk for toxic side effects from these medicines. In the 1960's ophthalmic reseachers at NYU (Dr. White's alma mater) demonstrated that chloroquine has an irreversible toxicity that causes blindness once you take a certain amount.

Thankfully, the development of hydroxychloroquine or Plaquenil has allowed people to obtain the pain relief with a much lower incidence of toxicity, and the toxic effects can be stopped and often reversed if the medicine is no longer taken. Approximately 8 patients out of every 1000 are diagnoses with toxicity each year. In order to prevent this some screening guidelines have been developed which were recently updated.

If you take Plaquenil you should see an eye doctor trained to rule out toxicity. 200 mg (1 pill) each day means an annual exam, and 400 mg (2 pills) each day requires a follow-up exam every 6 months. At least once each year a central visual field (VF) should be performed. The most recent recommendations say that an OCT should be done as well. We expect that additional testing will be requested as more information about this medicine continues to become available. Check back here for periodic  updates.

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