For hydroxychloroquine, Wikipedia has the following summary, with citation (and figures confirmed in the abstract): > The therapeutic, toxic and lethal ranges

For hydroxychloroquine, Wikipedia has the following summary, with citation (and figures confirmed in the abstract): > The therapeutic, toxic and lethal ranges are usually considered to be 0.03 to 15 mg/l, 3.0 to 26 mg/l and 20 to 104 mg/l, respectively. However, nontoxic cases have been reported up to 39 mg/l, suggesting individual tolerance to this agent may be more variable than previously recognised. For chloroquine, it just says it is "known to be small" (with citation, though I can't see the full PDF to see what "small" means).