In patients undergoing major abdominal surgery, alvimopan accelerated gastrointestinal recovery and time to the hospital discharge order written compared with placebo and was well tolerated.

Eicosanoids are biologically active lipid signaling molecules derived from polyunsaturated fatty acids. Many of the actions of eicosanoid metabolites formed by cyclooxygenase and lipoxygenase enzymes have been characterized, however, the epoxy-fatty acids (EpFAs) formed by cytochrome P450 enzymes are newly described by comparison. The EpFA metabolites modulate a diverse set of physiologic functions that include inflammation and nociception among others. Regulation of EpFAs occurs primarily via release, biosynthesis and enzymatic transformation by the soluble epoxide hydrolase (sEH). Targeting sEH with small molecule inhibitors has enabled observation of the biological activity of the EpFAs in vivo in animal models, greatly contributing to the overall understanding of their role in the inflammatory response. Their role in modulating inflammation has been demonstrated in disease models including cardiovascular pathology and inflammatory pain, but extends to neuroinflammation and neuroinflammatory disease. Moreover, while the EpFA demonstrate activity against inflammatory pain, interestingly, this action extends to blocking chronic neuropathic pain as well. This review outlines the role of modulating sEH and the biological action of EpFA in models of pain and inflammatory diseases.

Nalbuphine is a potent analgesic with a low side effect and dependence profile in animals and man. Nalbuphine is distinguished from other agonist/antagonist analgesics in having greater antagonist activity and fewer behavioral effects at analgesic doses than pentazocine, butorphanol or buprenorphine. At equi-analgesic doses, nalbuphine is quantitatively similar to nalorphine in regard to its large ratio of antagonist to analgetic activity. Clinical studies have confirmed this balance of strong antagonist to analgesic activity. Nalbuphine has been shown to effectively antagonize the respiratory depressant activity of narcotic analgesics while concomitantly adding to their analgetic responses. Unlike nalorphine or pentazocine, nalbuphine produces few overt behavioral or autonomic effects in animals at doses over 300 times its analgesic range. These findings are confirmed by clinical results which show that nalbuphine produces few psychotomimetic effects, even at elevated dose levels, in contrast to nalorphine or pentazocine. Nalbuphine produces limited respiratory depression in animals and in man. Significant cardiovascular effects have not been found. Nalbuphine was found to produce significantly less inhibition of gastrointestinal activity than any of the clinically useful narcotic or agonist/antagonist analgesics tested in animals. Nalbuphine's analgetic effects are reversed by naloxone doses similar to those which reverse nalorphine's agonist effects. Results in this and other tests suggest that nalbuphine is primarily a kappa-agonist/mu-antagonist analgesic. Unlike pentazocine or buprenorphine, nalbuphine does not suppress the narcotic abstinence syndrome in partly-withdrawn morphine-dependent animals or man. Rather, due to nalbuphine's strong antagonist activity, analgesic-range doses of nalbuphine severely exacerbate the withdrawal syndrome in partly-withdrawn mice, monkeys and humans. Nalbuphine also precipitates a strong abstinence response in non-withdrawn morphine-dependent animals and man. In post-addict humans, analgesic-range doses of nalbuphine are perceived as minimally morphine-like, but higher doses are judged to be progressively more nalorphine-like (i.e. dysphoric), which further limits nalbuphine's abuse potential in drug-seeking individuals. Primary dependence studies have demonstrated that physical dependence is possible at high dose levels that produce marked side effects. Other studies show that dependence is unlikely to be of significance within nalbuphine's usual analgesic range. Six-month studies in patients with chronic pain have confirmed that analgesic tolerance or physical dependence is uncommon.(ABSTRACT TRUNCATED AT 400 WORDS)

A length-dependent neuropathy with pain in the feet is a common complication of diabetes (painful diabetic neuropathy, PDN). It was hypothesized that pain may arise from sensitized-hyperactive cutaneous nociceptors, and that this abnormal signaling may be reduced by topical administration of the α2-adrenergic agonist, clonidine, to the painful area. This was a randomized, double-blind, placebo-controlled, parallel-group, multi-center trial. Nociceptor function was measured by determining the painfulness of 0.1% topical capsaicin applied to the pre-tibial area of each subject for 30 minutes during screening. Subjects were then randomized to receive 0.1% topical clonidine gel (n=89) or placebo gel (n=90) applied t.i.d. to their feet for 12 weeks. The difference in foot pain at week 12 in relation to baseline, rated on a 0-10 numerical pain rating scale (NPRS), was compared between groups. Baseline NPRS was imputed for missing data for subjects who terminated the study early. The subjects treated with clonidine showed a trend toward decreased foot pain compared to the placebo-treated group (the primary endpoint; p=0.07). In subjects who felt any level of pain to capsaicin, clonidine was superior to placebo (p<0.05). In subjects with a capsaicin pain rating ≥2 (0-10, NPRS), the mean decrease in foot pain was 2.6 for active compared to 1.4 for placebo (p=0.01). Topical clonidine gel significantly reduces the level of foot pain in PDN subjects with functional (and possibly sensitized) nociceptors in the affected skin as revealed by testing with topical capsaicin. Screening for cutaneous nociceptor function may help distinguish candidates for topical therapy for neuropathic pain.

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