How long does cocaine stay in your system?

That depends on the individual and other drugs that may be used at the same time (and slow breakdown) and the site used for testing. The time for 1/2 to be broken down/leave is 30-90 min if used alone. (the half life) 4 half lives is the usual time a drug is expected to be gone. However, trace amounts may be found in hair or other sites sampled by some testing programs.

A bit complex as a one-time dose does not last as long as chronic dosing. Serum levels can be detected for about 4 hrs., saliva about 8 hrs. In some chronic abusers, serum levels have been noted at over 50 hrs. Therefore, potential toxicity to brain or heart can last for a few days, even if discontinued.