https://www.ncbi.nlm.nih.gov/pubmed/8674334
You can overdose on it if you take more than 1.7 grams. The recommended dose is 400mg. For reference, you can overdose on tylenol and die if you take 4 times the recommended dosage.
The retinopathy happens after several years of taking the drug for rheumatoid arthritis. The course of treatment is six days for coronavirus.