opioid drug pathway hydrocodone drug pathway 2016-01-26T10:01:04Z PW:0002450 The pharmacokinetics and pharmacodynamics pathway of hydrocodone, a narcotic analgesic synthesized from codeine and used for relief of moderate to severe pain. It is also used as an antitussive to treat cough. Genetic variations can result in changes in drug availability and can cause differences in the response of the organism to the drug. pathway vpetri