How can i pass a drug test with slo niacin?

You can't: I would no more tell anybody how to falsify a drug test, than I would tell someone how to fake their blood sugar. You are responsible for the consequences of your actions, including drug use. Drug tests have become very sophisticated, and both the tests and those using them have become quite good at detecting methods to falsify results. Consider getting help for drug problem rather than passing.

Don't take drugs.: Taking Niacin alone would be fine for a drug test, of course.