Pain
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Randomized Controlled Trial
Safety, Tolerability, Pharmacokinetics, and Effects on Human Experimental Pain of the Selective Ionotropic Glutamate Receptor 5 (iGluR5) Antagonist LY545694 in Healthy Volunteers.
The objective of this study was to establish in healthy volunteers the maximally tolerated multiple dose (MTMD) of the ionotropic glutamate receptor 5 antagonist LY545694 (part A), and to investigate whether that dose had analgesic or antihyperalgesic effects in the brief thermal stimulation (BTS) pain model (Part B). Part A was a double-blind, placebo-controlled study in 3 groups of 10 healthy men. To simulate an extended-release formulation, study drug was administered orally over 6hours (12 equally divided aliquots at 30-minute intervals). ⋯ Neither gabapentin nor LY545694 reduced the painfulness of skin heating during BTS model induction. The most common treatment-emergent adverse event was dizziness. The results of this study suggest that LY545694 should be explored further as a potential treatment for chronic pain involving neuronal sensitization.
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Randomized Controlled Trial
Adaptability To Pain Is Associated With Potency Of Local Pain Inhibition, But Not Conditioned Pain Modulation: A Healthy Human Study.
This study investigated the relationship between pain sensitivity, adaptability, and potency of endogenous pain inhibition, including conditioned pain modulation (CPM) and local pain inhibition. Forty-one healthy volunteers (20 male, 21 female) received conditioning stimulation (CS) over 2 sessions in a random order: tonic heat pain (46 °C) on the right leg for 7 minutes and cold pressor pain (1 °C to 4 °C) on the left hand for 5 minutes. Participants rated the intensity of pain continuously using a 0 to 10 electronic visual analogue scale. ⋯ However, increased homotopic PPTs measured 20 minutes after CS correlated with the amount of pain reduction during CS. These results suggest that individual sensitivity and adaptability to pain does not correlate with the potency of CPM. Adaptability to pain is associated with longer-lasting local pain inhibition.
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Randomized Controlled Trial
A randomized, double blind, double dummy comparison of short- and long-acting dihydrocodeine in chronic non-malignant pain.
Guidelines for opioid treatment of chronic non-malignant pain recommend long-acting over short-acting opioid formulations. The evidence for this recommendation is weak. This study is a randomized, double-blind, double-dummy, 8-week comparison of long-acting dihydrocodeine tablets (DHC-Continus) with short-acting dihydrocodeine tablets in 60 patients with chronic non-malignant pain who were referred to a multidisciplinary pain clinic. ⋯ Breakthrough pain was experienced in both groups during the trial. Long-acting dihydrocodeine was not observed to be superior for any of the outcomes in this trial. The results of this study do not support current guidelines recommending long-acting opioids.