text_1: A 100g dose of chloroquine chemoprophylactic regimen results in retinal toxicity after 1 year of weekly intake.
text_2: A number of strategies are used during long-term stays: discontinuation of chemoprophylaxis after the initial period, sequential regimens with different medications for chemoprophylaxis, stand-by emergency self-treatment, and seasonal chemoprophylaxis targeting high-incidence periods or locations.