Pain
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Thirty-five cancer patients, treated with chronic epidural morphine, were assayed for plasma and cerebrospinal fluid (CSF) minimum steady-state concentrations (Css min) of morphine (M), morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G) by high performance liquid chromatography (HPLC). A linear dose-concentration relationship was found for the 3 substances in plasma and for morphine and M3G in CSF. The mean +/- S. ⋯ CSF M6G concentrations were low and did not contribute to any detectable analgesia. We conclude that after epidural administration of morphine, the M3G and M6G metabolites in CSF are low compared to unchanged morphine and seem to have little influence on analgesia. However, the fact that a significant passage of the glucuronide metabolites occurs to the CSF may indicate a role in morphine analgesia after other routes of administration.
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Twenty pancreatic cancer patients were studied to assess the effectiveness and duration of celiac plexus block compared to traditional treatment with analgesics by considering the previous and subsequent consumption of narcotics until their death. After 1 week of therapy with NSAID-narcotic sequence according to the WHO method, 10 patients were continued on this treatment, while the other 10 patients underwent celiac plexus block. ⋯ Celiac plexus block made pain control possible with a reduction in opioid consumption for a mean survival period of about 51 days. Administration of only analgesics resulted in an equal reduction in VAS pain score until death, but with more unpleasant side effects than when using celiac plexus block.
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Methadone is a synthetic opiate receptor agonist that has been available for more than 40 years. Although its main use has been in the maintenance treatment of opioid addicts, it has excellent analgesic effects and low cost. ⋯ Methadone should be titrated carefully and individualized doses and intervals should be determined for each patient. Future research should attempt to determine the equi-analgesic dose for chronic use, its effectiveness and tolerance when used in high doses, and its absorption and tolerance using alternative routes, e.g., rectal and subcutaneous.
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Recently it has been shown that placement of 4 loose chromic gut sutures around the rat sciatic nerve produces hyperalgesia. A possible mechanism underlying this hyperalgesia is a preferential loss of large myelinated fibers. A difficulty, however, is that neuropathic symptoms are not static and the time course of the axon loss has not been determined. ⋯ In addition, at 28 days post surgery there are essentially no large myelinated axons in the distal segment, but the signs of hyperalgesia have almost resolved. These findings indicate that the onset of the hyperalgesia is accompanied by a preferential loss of large fibers and by a lesser but still substantial loss of small myelinated and unmyelinated axons. The subsequent course of the hyperalgesia, however, is not in any obvious way related to the proportions of large myelinated fibers in the affected nerve.
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Tenderness and pain thresholds in pericranial muscles were studied in a random sample of 735 adults aged 25-64 years. This study was a part of a multifaceted, epidemiological study of different headache disorders. Manual palpation and pressure pain threshold were performed by observers blinded to the persons' history of headache. ⋯ A significant relation of tenderness to the recency of last episode of headache was detected in both sexes after control for usual frequency and actual headache (males: P < 10(-3); females: P < 10(-4)). Pressure pain thresholds were largely normal indicating normal pain processing and contradicting the idea that tension-type headache mainly is due to generally increased pain sensitivity. This study supports the pathogenetic importance of muscular factors in tension-type headache, while muscular factors are of no primary importance in migraine.