On an average Hydrocodone do stays upto four days in the body. The pain relief effect of Hydrocodone will wear off within four to six hours. The presence of Hydrocodone can be detected in saliva for upto 36 hours, in urine for four days and in hair for around 90 days. Side effects of Hydrocodone If Hydrocodone is taken is in proper and prescribed manner then Hydrocodone gives best result otherwise improper intake shall lead to several side effects. In case of addiction it can become habit forming too. So caution is necessary. Hydrocodone may cause serious life threatening issues like breathing problems. Below are certain side effects of Hydrocodone : Nausea Yellowish eyes Sore throat Unusual bleeding Severe headache Constipation Lightheadness Dizziness Drowsiness Blurred vision Consult the doctor immediately in above such side effects to reduce the effects of same.