Opiates, naturally occurring alkaloids, are found in opium poppy plants, and relieve pain symptoms. Drugs in this family include heroin, opium, morphine and codeine, reports opium.com.
The American Society of Addiction Medicine classifies opioids, which are at least partially synthetically produced, in two categories: illicit, which is where heroin falls; and licit, which are prescription pain relievers that include oxycodone, hydrocodone, codeine, morphine and fentanyl.
These drugs are chemically related and interact with opioid receptors on nerve cells in the brain and nervous system to produce pleasurable effects and relieve pain.