Brand named as Phenergan with Codeine or in generic form as promethazine with codeine. Opioids include substances such as heroin, morphine, fentanyl, codeine, oxycodone, and hydrocodone. Purdue Pharma makes pain medicines such as hydromorphone, oxycodone, fentanyl, codeine, and hydrocodone. It also has included 6 drugs namely Morphine, Fentanyl, Methadone, Oxycodone, Codeine and Hydrocodone. Those allergic to codeine may also be allergic to oxycodone. Compounded tablets with acetaminophen and codeine are also available. But cough syrup containing codeine and promethazine is banned, even with a prescription. The major psychoactive opiates are morphine, codeine, and thebaine. Morphine may also be metabolized into small amounts of normorphine, codeine, and hydromorphone. Opium can be manufactured into codeine and morphine, which are both legal pain-killers. CYP2D6 converts codeine into morphine, which then undergoes glucuronidation. Phenanthrenes such as morphine, codeine, and thebaine are the main psychoactive constituents. A combination of paracetamol, codeine, and the calmative doxylamine succinate is also available. Genetic differences between people give rise to differing rates of metabolism of codeine to morphine. A preparation of paracetamol and codeine is available in India.