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Chloroquine Retinopathy Ideal body weight Dr. F.R. Ochsendorf, Department of Dermatology, University Hospital, Theodor-Stern-Kai 7, D-60590 Frankfurt/M. (Germany) In this journal, Lipsker et al. [1] emphasized the efficacy of the combination of chloroquine and quinacrine for the treatment of resistant cutaneous lupus erythematosus. 20% of their patients (3/15), however, developed abnormalities in the electroretinogram resulting in cessation of chloroquine therapy. The authors state that ‘it seems very important that the daily dose of chloroquine and quinacrine should be as low as possible’. The daily dose according to the ideal body weight is the most relevant factor for the development of chloroquine retinopathy. This report as well as a survey [2] published recently demonstrate that hitherto the latter findings have not been adequately considered by the dermatological community. We therefore want to highlight this practically important topic. Chloroquine and hydroxychloroquine have been used in a restrictive manner only, which is due to the fear of development of irreversible chloroquine retinopathy. It is generally believed that chloroquine should not be given for longer than 1 year and the total cumulative dose should not exceed 100 g. A review of the literature published in this field, however, reveals that chloroquine therapy was considered too negatively in regard of the retinopathy. In the older studies, baseline examinations were often lacking. Furthermore up to now there are no reliable, generally accepted criteria for the diagnosis of chloroquine retinopathy. Therefore nearly each retinal deviation detected was suspected of being induced by chloroquine. In the meantime it was found that comparable changes (pigmentary changes, loss of the foveolar reflex and even the bull’s eye, etc.) can occur also in patients never treated with chloroquine [see references in 3 and 4]. The important new finding is that neither the duration of therapy nor the total cumulative dose are decisive for the development of retinopathy but solely the level of the daily dose [3-5]. The higher the daily dose, the more probable is the development of a retinopathy. Most retinopathies occurred at daily doses of 500 mg or more. At 250 mg/day, a retinopathy is rare (0.5-2%) [3]. If the daily chloroquine dose is limited to 3.5-4 mg/kg ideal body weight (or 6-6.5 mg/kg for hydroxychloroquine), however, a retinopathy does not appear. This is also true for patients who received chloroquine for several years with total cumulative doses of 1,000-2,500 g [5]. Mackenzie [5] followed more than 900 patients with a mean treatment time of 6.8 years and a mean total cumulative dose of about 608 g chloroquine (calculated). If 4 mg/kg ideal body