This newer atypical opioid is similar to tramadol in structure and mechanism of action: binding to opioid receptor is weak, and it acts mainly via monoaminergic pain mechanisms. Compared to tramadol, inhibition of norepinephrine transporter (NET) is more marked than that of SERT; thus, it primarily activates central noradrenergic pathways to elicit analgesia

Tapentadol is well absorbed orally, largely glucuronide conjugated, and the metabolite is excreted in urine. It is useful in the treatment of moderately severe pain conditions, and appears to be at least as effective as tramadol, but head-to-head comparative data is inadequate to establish relative efficacy. 

Tapentadol is a centrally-acting synthetic analgesic. Although their clinical relevance is unclear, tapentadol is believed to have two main mechanisms of action. Tapentadol is a selective mu-opioid receptor (MOR) agonist: it binds to MOR with an affinity greater than or equal to ten fold affinity compared to delta- and kappa-opioid receptors. Tapentadol also inhibits noradrenaline reuptake, thereby increasing noradrenaline levels and activating alpha-2 receptors to promote analgesia. Tapentadol is a weak serotonin reuptake inhibitor; however, this action does not contribute to its analgesic effect.

Tapentadol, in a single molecule, is a novel analgesic with a dual mode of action as an agonist of the opioid receptor (MOR), and as a norepinephrine reuptake inhibitor (NRI). Its analgesic merits begin quickly, at around 30 m for both acute nociceptive and chronic neuropathic pain. The drug has a representative default, with the tablet containing both an MOR agonist and an NRI. 

Tapentadol is used to help relieve moderate to severe short-term pain (such as pain from an injury or after surgery). It belongs to a class of drugs known as opioid analgesics. It works in the brain to change how your body feels and responds to pain.

Side effects are similar to tramadol, but nausea and vomiting appears to be less troublesome. However, it can trigger 'serotonin syndrome" in patients treated with SSRIs, and carries risk of precipitating seizures in predisposed patients. Thus, tapentadol is a useful alternative to tramadol for acute as well as chronic pain of moderate severity.

Suddenly stopping this medication may cause withdrawal, especially if patient have used it for a long time or in high doses. To prevent withdrawal, doctor may lower the dose slowly. Tell your doctor or pharmacist right away if you have any withdrawal symptoms such as restlessness, mental/mood changes (including anxiety, trouble sleeping, thoughts of suicide), watering eyes, runny nose, nausea, diarrhea, sweating, muscle aches, or sudden changes in behavior.

When this medication is used for a long time, it may not work as well. Do not use tapentadol if you have used a MAO inhibitor in the past 14 days. A dangerous drug interaction could occur. MAO inhibitors include isocarboxazid, linezolid, methylene blue injection, phenelzine, rasagiline, selegiline, or tranylcypromine.

Tapentadol may be habit-forming, even at regular doses. Patient should take this medicine exactly as prescribed by doctor. Never share the medicine with another person. Misuse of narcotic pain medication can cause addiction, overdose, or death, especially in a child or other person using the medicine without a prescription. Keeping the medication in a place where others cannot get to it.