Mechanistic and functional differentiation of tapentadol and tramadol

Abstract

Introduction: Many opioid analgesics share common structural elements; however, minor differences in structure can result in major differences in pharmacological activity, pharmacokinetic profile, and clinical efficacy and tolerability.

Areas covered: This review compares and contrasts the chemistry, pharmacodynamics, pharmacokinetics, and CNS ‘functional activity' of tapentadol and tramadol, responsible for their individual clinical utilities.

Expert opinion: The distinct properties of tapentadol and tramadol generate different CNS functional activities, making each drug the prototype of different classes of opioid/nonopioid analgesics. Tramadol's analgesia derives from relatively weak µ-opioid receptor (MOR) agonism, plus norepinephrine and serotonin reuptake inhibition, provided collectively by the enantiomers of the parent drug and a metabolite that is a stronger MOR agonist, but has lower CNS penetration. Tapentadol's MOR agonist activity is several-fold greater than tramadol's, with prominent norepinephrine reuptake inhibition and minimal serotonin effect. Accordingly, tramadol is well-suited for pain conditions for which a strong opioid component is not needed—and it has the benefit of a low abuse potential; whereas tapentadol, a schedule-II controlled substance, is well-suited for pain conditions requiring a strong opioid component—and it has the benefit of greater gastrointestinal tolerability compared to classical strong opioids. Both drugs offer distinct and complementary clinical options.

Keywords::

• analgesia
• efficacy
• MOR-NRI
• synergy
• tapentadol
• tramadol
• translational drug design

Notes

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