Clinical Examples in Managing Patients Taking 4-Aminoquinolines

Abstract

Overdosing is the most important factor contributing to 4-aminoquinoline retinopathy (4AQR). Proper interpretation of ancillary test results requires estimation of the pretest probability of 4AQR based on height, weight, daily dosage, duration of therapy, and the presence of renal and liver disease. An abnormal trend of an ancillary test over time carries greater weight than a single abnormal test. Shortening follow-up intervals and adding complementary ancillary tests are proper responses to a mild suspicion of 4AQR after screening. Reducing dosage, shortening follow-up, and adding complementary tests are proper responses to moderate suspicion of 4AQR without certainty. Cessation of the 4AQ is the proper response if the estimated probability of 4AQR is high. Obtaining the correct test is useless if it is misinterpreted; therefore, refining skills in interpreting tests is worthwhile. A checklist of risk factors can help to avoid overlooking information affecting the probability of retinopathy. The normal fellow eye is scrutinized for evidence of retinopathy in screening patients with unilateral preexisting maculopathy. In cases with bilateral preexisting maculopathy, more weight is placed on optimizing modifiable risk factors (e.g., safer daily dosing based on the lesser of ideal and actual body weight). Although rare, cases of 4AQR do occur in properly dosed patients, especially if the cumulative dose is high. One should not screen for 4AQR with the 24-2 or 30-2 visual field; it is better to use the 10-2 VF. In patients with glaucoma who take 4AQs, it is better to follow the glaucoma and screen for 4AQR with separate visual field protocols dedicated to the particular purpose rather than to use the 24-2 or 30-2 VF to investigate both problems.