You need to ask the. Doctor who prescribed it, or the pharmacist who filled the prescription. If it is not prescribed, the answer is easy - zero. The safe dose is not only limited by the amount of hydrocodone, but more so by the amount of Acetaminophen (apap). The current recommendation is no more than 2 grams/day for chronic users, and never more than 4 grams per day. If your pills have 325 mg, that is 6 pills/day.