Opiates are derived from the opium poppy plant and are highly addictive. Addiction can occur after just one use and withdrawal symptoms can be severe, including muscle pain, vomiting, and even coma or death. Prescription painkillers like morphine, oxycodone, and codeine work by blocking opioid receptors in the brain to dull pain, but carry risks of overdose and addiction. Heroin is made from morphine and causes euphoria and other effects, but can also lead to death from overdose or infections from injection.