Abstract
Tramadol is an opioid analgesic which is prescribed worldwide. Hydrochloride oral and injectable formulations have been approved for cancer pain and postoperative pain (injection only) in Japan. In addition, tablets combining tramadol with acetaminophen have been administrated for non-cancer pain and post-tooth-extraction pain. Tramadol acts as a μ-opioid receptor agonist and inhibits the reuptake of serotonin and norepinephrine. Regarding the management of cancer pain, it is placed on the second step of the World Health Organization analgesic ladder. Tramadol is gradually coming into use as a relatively safe and less addictive drug among opioid analgesics for both cancer and non-cancer pain.
