How long are drugs detectable in a drug urine screen?

That all depends on the type of drug screen you are taking. If it is a general five panel, it tests for THC, cocaine, opiates, benzos (Xanax, Klonopin) methamphetamine and amphetamine. Only illicit...

Illegal drugs, not legal medical drugs.

It depends on the drug you are taking, how much of it, and how strong that specific amount was.

approximate detection periods for Urine drug test : Alcohol 3-7 days via Ethyl Gluconoride(EtG) Amphetamines (except meth) 1 to 5 days Methamphetamine 2 to 7 days Barbiturates (except phenobarbital)...

I know from experience that any urine drug screen can be passed by making an ultra concentrated tea made with a half box (9 bags) of Yogi Detox Tea and 4-5 cups water. Let it steep for a half hour....