Yes, it's fine to cleans/ flush your liver while taking pharmaceuticals (antidepressants and other kinds).
There is the possibility that the level of drugs in your blood will be a bit higher during the flush and a bit lower afterward (since the liver will be busy flushing and not as active detoxing your blood during the flush, and then it'll be cleaner afterward and detoxing your blood more effectively)...but most folks don't notice much of a difference.