Tapentadol

Tapentadol is an atypical opioid. It activates m-opioid receptors in the central and peripheral nervous systems and, through Gi/o proteins, inhibits adenylyl cyclase, thereby reducing cAMP production. This in turn inhibits presynaptic voltage-gated Ca2+ channels, preventing calcium ions from entering the cell and reducing the release of pain-related neurotransmitters such as glutamate and substance P, thereby decreasing pain signal transmission. It also activates postsynaptic potassium channels, causing membrane hyperpolarization and reducing the likelihood of neuronal firing. In addition, tapentadol inhibits the norepinephrine transporter, increasing norepinephrine levels in the synaptic cleft and enhancing norepinephrine signaling.