Tramadol is a synthetic opioid analgesic, meaning it is a type of pain medication. It is used to treat moderate to moderately severe pain. Tramadol works by binding to the opioid receptors in the brain and spinal cord, inhibiting the transmission of pain signals. In addition to its opioid effects, tramadol also has some weak effects on the reuptake of norepinephrine and serotonin, which may contribute to its analgesic properties.