Pain
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Clinical Trial
Methadone maintenance patients are cross-tolerant to the antinociceptive effects of morphine.
We have previously shown that methadone maintenance patients are hyperalgesic. Very little is known about the antinociceptive effects of additional opioids in these patients. This study (1) compared the intensity and duration of antinociceptive responses, at two pseudo-steady-state plasma morphine concentrations (C(SS1) and C(SS2)), between four patients on stable, once daily, doses of methadone and four matched control subjects; and (2) determined, in methadone patients, whether the antinociceptive effects of morphine are affected by changes in plasma R(-)-methadone concentration that occur during an inter-dosing interval. ⋯ The fluctuations that occurred in plasma R(-)-methadone concentration during an inter-dosing interval had little effect on patients' responses to morphine. Our findings suggest that methadone patients are cross-tolerant to the antinociceptive effects of morphine, and conventional doses of morphine are likely to be ineffective in managing episodes of acute pain amongst this patient group. Further research is needed to determine whether other drugs are more effective than morphine in managing acute pain in this patient population.
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Clinical Trial Controlled Clinical Trial
Osteoarthritis and its association with muscle hyperalgesia: an experimental controlled study.
Hypertonic saline effectively excites muscle nociceptors. Muscle hyperalgesia was assessed in osteoarthritis (OA) by intramuscular infusion of 0.5 ml hypertonic saline (6%) into the tibialis anterior muscle in humans. Patients (n=14) with OA in the lower extremities were compared with an equal number of age- and sex-matched healthy controls. ⋯ OA patients had increased pain intensity VAS after the infusion in the right leg compared with controls (P<0.05). Referred and radiating pain areas at 2 min post-infusion increased in OA patients and not in controls as compared with the local pain areas (P<0.05). It is concluded that muscle hyperalgesia and extended pain areas might be due to central sensitization caused by painful osteoarthritis.
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The purpose of this study was to investigate the prevalence of pain symptoms causing disabilities in every-day activities and their possible connection to depressive symptomatology. A representative sample of 12640 adults from the Hungarian population participated in a door-to-door survey about demographic variables, pain-associated disability, and depressive symptomatology. The overall prevalence of pain-associated disability was 32.7%, significantly lower in men, showing a significant increasing trend with age. ⋯ No significant gender difference was found in the co-occurrence of depressive symptoms. This survey concludes that pain symptoms constitute a substantial public health problem in the Hungarian population in forms of emerging disabilities and depression. Epidemiological studies offer a better understanding of sociodemographic differences in health status, and serve the better allocation of professional and economic resources.
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Randomized Controlled Trial Clinical Trial
Analgesic profile of peroral and topical ketoprofen upon low pH-induced muscle pain.
Topical analgesics are widely marketed for treatment of muscle and joint pain. We have recently developed a model of muscle pain and have used this model to evaluate the efficacy of commercially available topical and peroral ketoprofen in order to evaluate the time- and dose-dependence of analgesia. In the present study, we examined the dose- (0, 50, and 100 mg) and time-dependence (hourly to 8 h) of commercially available peroral and topical ketoprofen. ⋯ The apparent analgesia was rapid to develop but transient and pain ratings increased back to baseline values within 3 h for the 100 mg dose and within 2 h for the 50 mg dose. This data suggests that topical application of commercial gel-based systems does not provide long-lasting analgesia in the muscle when compared to perorally-dosed ketoprofen. In addition, the data show that even doses of 100 mg peroral ketoprofen do not provide complete relief of muscle pain.
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Irritable bowel syndrome (IBS) is one of the most common gastrointestinal illnesses and is characterized by altered visceral perception. Previous studies in IBS have failed to demonstrate altered somatic or cutaneous perception. The aims of the study were to determine whether IBS patients have visceral hypersensitivity and cutaneous heat-induced hyperalgesia restricted to lumbosacral dermatomes, consistent with a localized segmental mechanism. ⋯ However, they did not differ from controls on several personality trait measures. These results suggest that patients with IBS have visceral hyperalgesia and cutaneous hyperalgesia that is distributed over a considerable rostral-caudal distance yet optimally expressed in lumbosacral dermatomes. This distribution is consistent with patterns of spinal hyperexcitability observed in experimentally induced persistent pain conditions.