How long does Vicodin stay in your system? After using Vicodin, its effects can be felt from four to eight hours later. And the most commonly used drug test can detect Vicodin for two to four days following the previous consumption. Vicodin contains the opioid hydrocodone, a semi synthetic drug created from codeine to test for Vicodin. Or hydrocodone use in general, urine, hair, saliv... https://secondnewlife.com/how-long-does-vicodin-stay-in-your-system/