Max dose recommended by doctors is 400 mg. I´ve read about cases where people were prescribed even more than that though on daily basis. Overdose depends on a lot of factors like age or weight. Find your limit of how much mg you can take until you get a headache, which is beginning of serotonin syndrome, afterwards triple the dose or go even higher if you want to fuck yourself up. Keep in mind that its not fatal though. I haven´t read about anyone dying from serotonin overdose yet, maybe if you take antiemetics with alcohol and go for like 2000 + mg it could be potentially fatal.