Pain
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Randomized Controlled Trial
Lamotrigine for treatment of pain associated with diabetic neuropathy: results of two randomized, double-blind, placebo-controlled studies.
To assess the efficacy and tolerability of lamotrigine in pain associated with diabetic neuropathy, two replicate randomized, double-blind, placebo-controlled studies were conducted. Patients (n=360 per study) with painful diabetic neuropathy were randomized to receive lamotrigine 200, 300, or 400 mg daily or placebo during the 19-week treatment phase, including a 7-week dose-escalation phase and a 12-week, fixed-dose maintenance phase. The mean reduction in pain-intensity score from baseline to week 19 (primary endpoint) was greater (p < or = 0.05) in patients receiving lamotrigine 400 mg than placebo in Study 2 (observed scores, -2.7 versus -1.6 on a 0- to 10-point scale). ⋯ Adverse events were reported in 71-82% of lamotrigine-treated patients compared with 63-70% of placebo-treated patients. The most common adverse events with lamotrigine were headache and rash. Compared with placebo, lamotrigine (300 and 400 mg daily) was inconsistently effective for pain associated with diabetic neuropathy but was generally safe and well tolerated.
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We examined between and within-person variability, affective correlates, and diagnostic differences in daily fatigue in women with rheumatoid arthritis (RA), osteoarthritis (OA), and fibromyalgia syndrome (FMS). Two hundred and fifty-five female patients recruited from the community served as participants for this project. The patients had a physician-confirmed diagnosis of RA (n=89), OA (n=76), or FMS (n=90). ⋯ Daily pain was associated with increased fatigue in all groups, although OA patients showed less pain reactivity than either FMS or RA patients. These findings indicate that fatigue is a common feature of rheumatologic conditions. Nonetheless, there are important differences between RA, OA, and FM patients in both the everyday manifestations and the biopsychosocial correlates of fatigue.
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Previous neuroimaging studies have shown brain activity during not only the application of noxious stimuli, but also prior to stimulation. The functional significance of the anticipatory response, however, has yet to be explored. Two theoretical responses involve either a decrease or an increase in sensitivity of the nociceptive system. ⋯ Results of this regression analysis revealed that insula activity during receipt was predicted by activity in both the entorhinal cortex and VTA during anticipation. We suggest that activation in both regions before and during pain may underlie anticipation and subsequent pain modulatory responses, possibly involving the appraisal and control of attention necessary for pain modulation. Together, the results suggest a possible role of brainstem areas in anticipatory mechanisms involved in the maintenance of chronic pain.
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Randomized Controlled Trial
Classical conditioning and expectancy in placebo hypoalgesia: a randomized controlled study in patients with atopic dermatitis and persons with healthy skin.
The effectiveness of placebos is unchallenged. However, it is still not clear on which mechanisms the placebo effect is based. Besides expectancy theories, classical conditioning is discussed as a major explanatory model. ⋯ However, conditioning processes seem to be necessary for a longer lasting effect. The extent of this effect seemed to be greater in atopics than in healthy controls. Expectancy, achieved through verbal instruction, might also be seen as a conditioned stimulus that reactivates earlier stimulus associations.