I-mask suggests 40mg/kg so it would depend on your weight (in kilograms). I don’t know about interactions with any prescription meds, but I have read that any zinc iodophores (HCQ, Quercetin, EGCG in green tea, Nigella sativa, and others) should not be taken at the same time. Multiple can be taken, but spread out in the day.
Do you happen to recall where you read about the timing of taking zinc ionospheres?