Expert opinion on pharmacotherapy
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Expert Opin Pharmacother · Jul 2012
Review Comparative StudyPregabalin for the treatment of fibromyalgia.
Fibromyalgia (FM) is the most common cause of chronic widespread body pain in humans. Co-morbidities include sleep disturbance, fatigue, impaired physical functioning, altered mood and negative effects on health-related quality of life. Pregabalin inhibits presynaptic release of pronociceptive neurotransmitters in the CNS; this likely underpins its therapeutic benefit in patients with FM. ⋯ At the approved dosages, oral pregabalin has at most a moderate therapeutic benefit above placebo with tolerable side-effects, in no more than 50% of patients with FM. Durability of clinically meaningful (≥ 30%) pain relief in pregabalin-responders has been demonstrated for at least 6-months, but longer-term studies are required as most patients have symptoms for decades. Exclusion of patients with common co-morbidities from the pregabalin RCTs in FM raises questions on the generalizability of the RCT findings to the typical patient seen in clinical practice and so additional investigation is required.
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Expert Opin Pharmacother · Jul 2012
ReviewMechanistic and functional differentiation of tapentadol and tramadol.
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. ⋯ 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.