One such commonly used medication for dermatologic and rheumatologic inflammatory conditions is hydroxychloroquine (Plaquenil), a chloroquine derivative. It is used to treat many diseases including malaria, rheumatoid arthritis and systemic lupus erythematosus. Omphthamologists risks of hydroxychloroquine Fatcs on chloroquine Davis drug guide pdf hydroxychloroquine SD-OCT Unlike time domain optical coherence tomography, SD-OCT has the resolution to detect localized thinning of the retina in the parafoveal region. On SD-OCT, loss or thinning of the parafoveal and perifoveal photoreceptor layer and focal disruption of outer segment laminations are consistent with toxicity 13. In early cases of Plaquenil toxicity, an early indicator of damage is the appearance of a paracentral scotoma seen on automated visual field testing in the absence of fundus changes. 18 Each of the testing strategies can be used to detect early toxicity changes, but the presentation of the visual field effects will vary. Due to the central area being depressed in the 24-2 and 30-2 testing strategies, it is difficult to discern the central 2-degree field of sparing seen in the 10-2 tests. Plaquenil toxicity first affects small areas of the retina between 5° and 15° from the fovea. Figures 2 and 3 show three patients at different stages of toxicity. Figure 2 bottom right shows a color display of normal mfERGs. The amplitude of the mathematically derived b-wave of the mfERG is displayed in a color scale. It is imperative that patients and physicians are aware of and watch for this drug’s ocular side effects. Retinal toxicity from hydroxychloroquine is rare, but even if the medication is discontinued, vision loss may be irreversible and may continue to progress. Oct appearance of plaquenil toxicity Early Plaquenil Toxicity Detected without Bull’s Eye., How to Succeed in Plaquenil Screenings Chloroquine cytotoxic hemozoin falicparum The risk of a toxicity sharply increases after 5 years, with majority of cases of retinotoxicity occurring in patients that have had a cumulative dose exceeding 1000g of hydroxychloriquine Plaquenil. This level is reached in about 7 years with the most common daily dose of Plaquenil, 400 mg/day 200 bid. Plaquenil Risk Calculators. Retina Today - Evaluating Hydroxychloroquine Toxicity With Multifocal.. Recommendations on Screening for Chloroquine and.. The toxicity resulting from the intake of Plaquenil is due to its affinity for melanin-containing structures in the body. With prolonged usage, metabolites in the drug accumulate in the retina. The drug remains in these parts even if the patients stopped taking the drugs. Aug 06, 2014 Previously described OCT findings in HCQ toxicity include loss of the external limiting membrane, disruption of the outer ellipsoid zone, parafoveal thinning of the outer nuclear layer and RPE damage. 6,7,10 Despite these various changes, numerous studies have supported the notion that relative “foveal resistance” is common in HCQ toxicity, as demonstrated by preservation of the subfoveal outer retinal layers, accounting for the intact central visual acuity that can be seen even in. Symptoms of Plaquenil toxicity are similar to other macular problems and may include Decreased fine vision or difficulty reading. Changes in Color vision. Missing Spots or shadows near the center of the vision.