Tramadol is a prescription medication used to treat moderate to moderately severe pain. It is classified as an opioid analgesic, although its mechanism of action differs from that of traditional opioids. Tramadol works by binding to mu-opioid receptors in the brain and spinal cord, blocking the transmission of pain signals. It also inhibits the reuptake of serotonin and norepinephrine, which may contribute to its analgesic effects.