Pain
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Case Reports Randomized Controlled Trial Comparative Study
Drug-induced liver injury following a repeated course of ketamine treatment for chronic pain in CRPS type 1 patients: a report of 3 cases.
Studies on the efficacy of ketamine in the treatment of chronic pain indicate that prolonged or repetitive infusions are required to ensure prolonged pain relief. Few studies address ketamine-induced toxicity. Here we present data on the occurrence of ketamine-induced liver injury during repeated administrations of S(+)-ketamine for treatment of chronic pain in patients with complex regional pain syndrome type 1 as part of a larger study exploring possible time frames for ketamine re-administration. ⋯ In all patients, the ketamine infusion was promptly terminated and the liver enzymes slowly returned to reference values within 2 months. Our data suggest an increased risk for development of ketamine-induced liver injury when the infusion is prolonged and/or repeated within a short time frame. Regular measurements of liver function are therefore required during such treatments.
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Comparative Study
Eugenol reverses mechanical allodynia after peripheral nerve injury by inhibiting hyperpolarization-activated cyclic nucleotide-gated (HCN) channels.
Mechanical allodynia is a common symptom found in neuropathic patients. Hyperpolarization-activated cyclic nucleotide-gated channels and their current, I(h), have been suggested to play an important role in neuropathic pain, especially in mechanical allodynia and spontaneous pain, by involvement in spontaneous ectopic discharges after peripheral nerve injury. Thus, I(h) blockers may hold therapeutic potential for the intervention of mechanical allodynia under diverse neuropathic conditions. ⋯ Eugenol-induced I(h) inhibition was not mediated by G(i/o)-protein activation, but was gradually diminished by an increase in intracellular cAMP concentration. Eugenol also inhibited I(h) from injured TG neurons which were identified by retrograde labeling with DiI and reversed mechanical allodynia in the orofacial area after chronic constriction injury of infraorbital nerve. We propose that eugenol could be potentially useful for reversing mechanical allodynia in neuropathic pain patients.
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Randomized Controlled Trial Comparative Study
Targeting temporomandibular disorder pain treatment to hormonal fluctuations: a randomized clinical trial.
Mounting evidence supports the importance of hormonal fluctuations in temporomandibular disorder (TMD) pain among women. Stabilizing influential hormones or having a plan and skills for coping with hormonally related increases in TMD pain, therefore, may be beneficial for women with TMD pain. This randomized clinical trial evaluated the short- and long-term efficacy of 3 interventions for women with TMD pain: (1) dental hygienist-delivered pain self-management training (SMT; n=59); (2) the same dental hygienist-delivered pain self-management training, but with a focus on menstrual cycle-related changes in pain and other symptoms (targeted SMT, or TSMT; n=55); and (3) continuous oral contraceptive therapy (6-month trial) aimed at stabilizing hormones believed to be influential in TMD pain (COCT; n=57). ⋯ The benefits of the self-management interventions relative to COCT for pain and activity interference were statistically significant at 12 months, but not at 6 months, whereas the benefits for the process measures generally were apparent at both time points. COCT was associated with multiple adverse events (none serious). The study provides further support for long-term benefits of a safe, low-intensity (2 in-person sessions and 6 brief telephone contacts), dental hygienist-delivered self-management treatment for TMD pain.
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Randomized Controlled Trial Multicenter Study Comparative Study
Efficacy of botulinum toxin type A for treatment of persistent myofascial TMD pain: a randomized, controlled, double-blind multicenter study.
Evidence of an effect by botulinum toxins is still lacking for most pain conditions. In the present randomized, placebo-controlled, crossover multicenter study, the efficacy of botulinum toxin type A (BTX-A) was investigated in patients with persistent myofascial temporomandibular disorders (TMD). Twenty-one patients with myofascial TMD without adequate pain relief after conventional treatment participated. ⋯ The number needed to treat was 11 after 1 month and 7 after 3 months. There were no significant changes after treatment in any other outcome measures, with the exception of pain on palpation, which decreased 3 months after saline injection (P<.05). These results do not indicate a clinical relevant effect of BTX-A in patients with persistent myofascial TMD pain.
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Comparative Study
Nerve growth factor selectively decreases activity-dependent conduction slowing in mechano-insensitive C-nociceptors.
Nerve growth factor (NGF) induces acute sensitization of nociceptive sensory endings and long-lasting hyperalgesia. NGF modulation of sodium channel expression might contribute to neurotrophin-induced hyperalgesia. Here, we investigated NGF-evoked changes of the activity-dependent slowing of conduction in porcine C-fibers. ⋯ Accordingly, the number of fibers with pronounced ADS decreased but more units with pronounced ADS were mechano-sensitive. Spontaneously active C-fibers were increased above the control level (1%) by NGF 8 μg (8%). The results demonstrate that NGF changes the functional axonal characteristics of mechano-insensitive C-fibers and enhances spontaneous activity thereby possibly contributing to hyperalgesia.