Norco is an opioid pain reliever that contains both hydrocodone and paracetamol. It is used to treat moderate to severe chronic and acute pain. Paracetamol suppresses prostaglandin production whereas hydrocodone acts on opioid receptors. If you buy Norco without a prescription, you run the danger of overdosing and, eventually, dependence. Norco is available in tablet, extended-release tablet, and syrup forms. It is taken orally and provides pain relief for four to six hours. Norco has been a brand name for hydrocodone bitartrate, which is used to treat moderate to severe pain, since its debut in 1958.