Meptazinol hydrochloride is primarily used as an analgesic for the relief of moderate to severe pain. It is often administered in clinical settings for postoperative pain management, providing effective relief while minimizing side effects commonly associated with other opioids. Its unique mechanism of action, which involves partial agonism at opioid receptors and cholinergic activity, makes it a suitable option for patients who may not tolerate stronger opioids well. Additionally, it is used in obstetrics for pain relief during labor, as it has a favorable safety profile for both the mother and the newborn. Its rapid onset of action and relatively short duration make it particularly useful in acute pain scenarios.