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
Tramadol is 
Select and explain. 
A. Antiflatulent, B. Antireflux drug, C. Beta-blocker, D. Opioid analgesic
D: Opioid analgesic
Answer: D: Opioid analgesic 
Explanation: 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.