The myotoxicity of chloroquine and hydroxychloroquine has been known for 
decades. Limb-girdle weakness due to a vacuolar myopathy may occur occasionally 
in a dose-dependent manner during the first 24 months on chloroquine. However, 
we report on a case in which muscular weakness developed after a daily intake of 
250 chloroquine phosphate (= 155 mg chloroquine base) for a period of 7 years. 
Even after long-term and apparently well-tolerated chloroquine treatment, the 
occurrence of severe side-effects is possible.