Tramadol 100mg is a prescription opioid analgesic used to treat moderate to moderately severe pain. It works by binding to opioid receptors in the brain and inhibiting the reuptake of serotonin and norepinephrine, enhancing pain relief. Tramadol 100mg is available in both immediate-release (IR) and extended-release (ER) formulations. The IR version provides pain relief for 4-6 hours, while the ER version is designed for chronic pain management, lasting up to 24 hours.