Tramadol is a prescription opioid pain reliever used to treat moderate to severe pain. It is available in both immediate-release and extended-release formulations. Tramadol is typically taken orally, but it can also be administered rectally or intravenously. Tramadol works by binding to opioid receptors in the brain and spinal cord. This binding inhibits the transmission of pain signals and produces a euphoric effect. Tramadol is less potent than other opioids, such as morphine or oxycodone, and it is generally considered to be less addictive.