This is a known effect, since the mid 50's due in part to actual events depicted in a somewhat dramatic fashion on M*A*S*H.
Chloroquine is still used almost exclusively to treat or prevent Malaria, either as Plaquenil or Primaquin, and in numerous rheumatological diseases as Plaquinil; however, it has hemolytic effects, especially in people with glucose-6-phosphate dehydrogenase deficiency (G6PD). The deficiency is found most prominently in those of African or Mediterrean descent.
Unfortunately, the medical approach seems to be try the medication regardless, and if symptoms develop, stop treatment. This is probably based on the fact that genetic testing prior to treatment, in order to discover the deficiency if it exists, is very expensive, and can't really be limited to specific patients for several reasons, one being the "medical racism" statement int he article you posted, and another being the possibility of the trait existing in just about anyone due to lost, unknown, or hidden genealogy records. I think the theory is, if symptoms develop, look to genetics as a possible cause, otherwise, be grateful that it's working.
Of course anyone with Sickle Cell Anemia, or with a first degree relative with it, should probably be considered at higher risk for the deficiency and more caution taken.
