An analgesic 'X' acts through opioid as well as additional spinal monoaminergic mechanisms. Which of the following can be 'X'?: (A) Tramadol, (B) Etioheptazine, (C) Dextropropoxyphene, (D) Alfentanil
Answer is A. -Tramadol and tapendadol have additional analgesic mechanisms apa from activation of opioid receptors. -These drugs increase release of serotonin in spinal cord and strengthen the descending inhibitory pathway.