Hydrocodone is a fairly common prescription-only painkiller medicine, which is used for the treatment of chronic and severe pain. The severe pain is caused by cancer, arthritis, and other problems in patients, which damages their body parts. It is also used to treat cough when combined with Antihistamine & Chlorpheniramine. But do you know, how long does Hydrocodone stay in your system for blood, saliva, and urine tests?