Hydrocodone (hye” droe koe’ done) is a semisynthetic derivative of codeine or thebaine, natural alkaloids derived from the resin of poppy seeds (Papaver somniferum). It is well absorbed orally and has moderate opiate activity (approximately 6 times that of codeine), acting an agonist of the µ opiate receptor. The combination of hydrocodone with acetaminophen is effective in ameliorating moderate-to-moderately severe pain and is widely used for temporary as well as chronic management of pain states. The combination of hydrocodone with acetaminophen or other products helps to prevent its recreational use and administration by injection. Hydrocodone has been in use since shortly after its initial synthesis in the 1920’s, but was formally approved for use in combination with acetaminophen in the United States in 1998. Current indications are for treatment of moderate-to-moderately severe pain (combinations with acetaminophen or ibuprofen) or alleviation of cough and symptoms of upper respiratory tract infections (combined with chlorpheniramine or homatropine). It is currently one of the most commonly prescribed drugs in medical practice. Hydrocodone is available in multiple formulations (tablets, capsules, syrup) combined with other analgesics, antihistamines or anticholinergics in concentrations of 2.5, 5, 7.5 and 10 mg generically and (with acetaminophen) under brand names such as Vicodin, Norco, Lortab and Co-Gesic, among others. The preparations are generally taken every 4 to 6 hours. Importantly, the dose of acetaminophen in hydrocodone combinations varies from 300 to 1000 mg per tablet. The FDA, however, has recommended that physicians not use opioid combinations with concentrations of acetaminophen of more than 325 mg per unit dose. Side effects of hydrocodone include sedation, respiratory depression, mental clouding, euphoria, agitation, constipation, diarrhea, abdominal bloating, nausea, vomiting, headache and dizziness. Long term use can be followed by withdrawal symptoms. Hydrocodone is a controlled substances and classified as a Schedule III drug, indicating that it has medical usefulness, but also a potential for physical and psychological dependency and abuse.