Generally, it takes between seven and 10 hours for a dog to digest food, but the many variables mean that only your vet can tell you how long it should be taking.
But how many days after Provera will your period start? When using Provera for amenorrhea (absence of menstrual periods) or abnormal vaginal bleeding, the medication is taken for 5 to 10 days. Menstrual-like vaginal bleeding usually occurs three to seven days after treatment ends.
Note: continued use of Depo-Provera may stop the menstrual cycle completely and it may take longer than average (9 months-1 year for the menstrual cycle to regulate after stopping it). Once you have gotten a shot of Depo-provera, side effects will not dissipate for 12-14 weeks.