fentanyl + morphine + paracetamol + tramadol

This is a combination drug consisting of four active ingredients—fentanyl, morphine, paracetamol (acetaminophen), and tramadol. All four are analgesics but act via different mechanisms to provide multimodal pain relief. Fentanyl and morphine are potent opioid agonists primarily targeting the μ-opioid receptor to inhibit pain transmission in the central nervous system. Tramadol is a centrally acting synthetic opioid that not only acts as a μ-opioid receptor agonist but also inhibits serotonin and norepinephrine reuptake, contributing additional analgesic effects[1][6]. Paracetamol is an analgesic and antipyretic agent with a mechanism believed to involve inhibition of prostaglandin synthesis in the central nervous system. The combination aims for synergistic pain control by leveraging both opioid and non-opioid pathways.