HYDROcodone Bitartrate (Antitussive) reference guide for safe and effective use from the American Society of Health-System Pharmacists (AHFS DI). Norco (hydrocodone bitartrate and acetaminophen) is an opioid analgesic and antitussive (cough suppressant) combined with a pain reliever (analgesic) used to treat moderate to fairly severe pain. Long-acting opioid pain medicines, such as hydrocodone bitartrate ER tablets, can put you at risk for overdose and death. Even if you take your dose correctly as prescribed, you are at risk for opioid addiction, abuse, and misuse that can lead to death. Hydrocodone is an opioid that binds to specific receptors in your body to give you pain relief. Common side effects may include constipation, dizziness, drowsiness, headache, and stomach pain. Hydrocodone bitartrate is a phenanthrene-derivative opiate agonist that is used as an analgesic and antitussive agent. Hydrocodone Bitartrate prescription and dosage information for physicians and health care professionals. Pharmacology, adverse reactions, warnings, and Hydrocodone Bitartrateside effects. Hydrocodone belongs to the group of medicines called opioid analgesics (pain medicines). It acts on the central nervous system (CNS) to relieve pain. When hydrocodone is used for a long time, it may become habit-forming, causing mental or physical dependence.