AIIMS PG Exam – 84928

Correct Answer » A Explanation

Ans. A. Serotonin and nor-adrenaline reuptake inhibition

* Tramadol differs from other traditional opioid medications in that it doesn’t just act as a μ-opioid agonist, but also affects monoamines by modulating the effects of neurotransmitters involved in the modulation of pain such as serotonin and norepinephrine which activate descending pain inhibitory pathways.

* Tramadol’s effects on serotonin and norepinephrine mimic the effects of other SNRI antidepressants such as duloxetine and venlafaxine.

* Tramadol exists as a racemic mixture consisting of two pharmacologically active enantiomers that both contribute to its analgesic property through different mechanisms and are also themselves metabolized into active metabolites: (+)-tramadol and its primary metabolite (+)-O-desmethyl-tramadol (M1) are agonists of the μ opioid receptor while (+)-tramadol inhibits serotonin reuptake and (-)-tramadol inhibits norepinephrine reuptake.

* These pathways are complementary and synergistic, improving tramadol’s ability to modulate the perception of and response to pain.