Order Hydrocodone online for the pain relief. It is the combination of hydrocodone and acetaminophen that is used to relieve severe pain that requires opioid treatment and when other pain relievers are not working well enough or are not tolerated. Acetaminophen is used in a great way to relieve pain and reduce fever in patients. It does not become a habit if it is taken over a long period. However, when taken in large doses, acetaminophen can cause other side effects, including liver damage.