Vicodin ER is an Extended-Release version of Vicodin tablets. And it consists of hydrocodone and acetaminophen as the main components of this drug. Order Vicodin ER online is an opioid that is used to treat pain. Be it severe or moderate. Acute or chronic. Vicodin comes under the category of opioid analgesics and thus, helps the person cope with pain. It helps in producing a calming effect on the body and mind of a person.