This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: C.N.S, Subject name: Pharmacology
[{'content': 'Tramadol is \nSelect and explain. \nA. Antiflatulent, B. Antireflux drug, C. Beta-blocker, D. Opioid analgesic', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Ans. d (Opioid analgesic). (Ref. KD Tripathi, Pharmacology/6th. 453)# Tramadol is synthetic centrally acting opioid analgesic having modest affinity for ji receptors.# Unlike other opioids, it inhibits reuptake of NA and 5-HT and thus activates monoaminergic spinal inhibition of pain.# Its oral bioavailability is good and it has minimal hemodynamic effects and hence safer in patients with compromised CVS function.# It is indicated for medium intensity short lasting pain due to diagnostic procedures, injury, surgery, etc as well as for chronic cancer pain.', 'role': 'assistant'}]