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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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 Comparative Study
Botulinum toxin injection for management of thoracic outlet syndrome: a double-blind, randomized, controlled trial.
We studied the effect of botulinum toxin type A (BTX-A) injections to the scalene muscles on pain in subjects with thoracic outlet syndrome (TOS) in this double-blind, randomized, parallel group trial with follow-up at 6 weeks, 3 months, and 6 months. Thirty-eight patients referred to physiatrists for management of TOS with BTX-A injection were included. One subject was lost to follow-up and all other subjects completed the trial. ⋯ For the primary outcome measure of VAS scores for pain at 6 weeks, the difference in the means adjusted for baseline VAS scores between placebo and BTX-A was 5.03 mm in favor of BTX-A (95% confidence interval -15.7 to 5.7, P=.36). Changes in secondary outcome measures were also not statistically significant. We conclude that BTX-A injections to the scalene muscles did not result in clinically or statistically significant improvements in pain, paresthesias, or function in this population of subjects with TOS.
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Comparative Study
Self-medication of a cannabinoid CB2 agonist in an animal model of neuropathic pain.
Drug self-administration methods were used to test the hypothesis that rats would self-medicate with a cannabinoid CB(2) agonist to attenuate a neuropathic pain state. Self-medication of the CB(2) agonist (R,S)-AM1241, but not vehicle, attenuated mechanical hypersensitivity produced by spared nerve injury. Switching rats from (R,S)-AM1241 to vehicle self-administration also decreased lever responding in an extinction paradigm. (R,S)-AM1241 self-administration did not alter paw withdrawal thresholds in sham-operated or naive animals. ⋯ Our results suggest that cannabinoid CB(2) agonists may be exploited to treat neuropathic pain with limited drug abuse liability and central nervous system side effects. These studies validate the use of drug self-administration methods for identifying nonpsychotropic analgesics possessing limited abuse potential. These methods offer potential to elucidate novel analgesics that suppress spontaneous neuropathic pain that is not measured by traditional assessments of evoked pain.