RESEARCH - Chloroquine/hydroxychloroquine: variability of retinotoxic cumulative doses

[Guest guest]

Ophthalmologe. 2007 Oct;104(10):875-9.

[Chloroquine/hydroxychloroquine: variability of retinotoxic cumulative doses

Rüther K, Foerster J, Berndt S, Schroeter J.

Charitè-Augenklinik Campus Virchow Klinikum, Augustenburger Platz 1,

13353, Berlin. klaus.ruether@...

OBJECTIVE: The critical dose of chloroquine/hydroxychloroquine leading

to a maculopathy or generalised retinopathy remains undetermined. In

the literature, 100 g is considered the dose at which regular vision

checks should be performed. Generally, chloroquine is said to be more

toxic than hydroxychloroquine. A young patient presenting with toxic

maculopathy after 57 g of hydroxychloroquine and a daily dosage of 2

mg/kg body weight prompted us to retrospectively look at our patients

examined in this respect over about 1 year. METHODS: The data of

patients who were examined because of chloroquine/hydroxychloroquine

intake or a respective maculopathy/retinopathy were retrospectively

analysed. The time period was January 2005 until March 2006. Retinal

damage was defined by fundus changes and alteration of the multifocal

electroretinogram (ERG). RESULTS: Twenty-one patients--18 women and

three men--were examined. The mean age was 51 years (range 6-71). Five

of the nine chloroquine-treated patients developed a maculopathy, and

one of them developed an additional generalised retinopathy. Of the

patients treated by hydroxychloroquine, three of 12 suffered from a

maculopathy and one from an additional generalised retinopathy. The

cumulative doses leading to retinal damage ranged from 170 g to 1650 g

for chloroquine and from 57 g to 1190 g for hydroxychloroquine. The

highest cumulative doses without leading to signs of retinopathy were

790 g for chloroquine and 1200 g for hydroxychloroquine. CONCLUSIONS:

There is a high variability of cumulative doses of

chloroquine/hydroxychloroquine that lead to a toxic retinopathy.

Therefore, early and regular ophthalmologic examinations are

recommended. Electrophysiological testing should be performed once a

year, corresponding to about 60 g of base with one tablet a day. For

electrophysiology, the multifocal ERG has turned out to be the most

important test in this regard. However, visual acuity and funduscopy

should be performed more frequently.

PMID: 17653725

http://www.ncbi.nlm.nih.gov/pubmed/17653725

--

Not an MD