Tuesday 2 September 2014

Plaquenil Screening

Plaquenil (hydroxychloroquine) and its cousin chloroquine are useful drugs - particularly for arthritis and some skin conditions.  Both drugs can cause significant damage to the retina which is usually irreversible.  Doctors have known for decades about the importance of  monitoring of all patients on long term plaquenil.

The technology for screening for plaquenil toxicity has evolved over recent years.  A nice review article can be found here.  There has been much enthusiasm recently for high resolution OCT scanning for detection of early plaquenil toxicity and this has in many doctors' practices been at the expense of visual field testing.

A case was recently seen where substantial and permanent visual loss resulted from plaquenil despite the regular OCT scans.

Our approach is now, where possible, do some baseline tests before the first dose of plaquenil.  This includes colour vision, central field and OCT.  We have found Fundus Autofluorescence (FAF) to be more effective than OCT in the detection of damage so for patients with more than 3 years of plaquenil treatment we recommend annual visual fields, FAF and OCT.

In cases where patients have been on Plaquenil and it is working for their joint symptoms but there is some suspicion of toxicity, we recommend the addition of a multifocal ERG test .  This is a test of the function of the retina rather than its structure which is tested by OCT and FAF

At our Essendon rooms  we can offer all of these types of tests as well as testing for a large range of other eye diseases