Ultram is a brand name for the medication tramadol. Tramadol is an opioid analgesic, which means it is a pain reliever. It is used to treat moderate to moderately severe pain. Tramadol works by binding to opioid receptors in the brain and spinal cord, inhibiting the transmission of pain signals. Tramadol is considered an opioid, but its mechanism of action is different from traditional opioids like morphine. In addition to its opioid activity, it also has some weak inhibition of the reuptake of serotonin and norepinephrine.