Pain
-
Clinical Trial
Lowering fear-avoidance and enhancing function through exposure in vivo. A multiple baseline study across six patients with back pain.
This study investigated the effects of an exposure in vivo treatment for chronic pain patients with high levels of fear and avoidance. The fear-avoidance model offers an enticing explanation of why some back pain patients develop persistent disability, stressing the role of catastrophic interpretations; largely fueled by beliefs and expectations that activity will cause injury and will worsen the pain problem. Recently, an exposure in vivo treatment was developed that aims to enhance function by directly addressing these fears and expectations. ⋯ These improvements were observed even though rated pain intensity actually decreased somewhat. Thus, the results replicate and extend the findings of previous studies to a new setting, with other therapists and a new research design. These results, together with the initial studies, provide a basis for pursuing and further developing the exposure technique and to test it in group designs with larger samples.
-
Intrathecal administration of serotonin type 2 (5-HT(2)) receptor agonists, alpha-methyl-5-hydroxytryptamine maleate (alpha-m-5-HT) or (+/-)-1-(4-iodo-2,5-dimethoxyphenyl)-2-aminopropane hydrochloride (DOI), produces antiallodynic effects in a rat model of neuropathic pain. In the present study, we examined the antiallodynic effects of intrathecally administered agents which are selective for 5-HT(2C) receptors. Allodynia was produced by tight ligation of the left L5 and L6 spinal nerves, and was measured by applying von Frey filaments to the left hindpaw. ⋯ The preferential 5-HT(2A) receptor antagonist ketanserin (30 microg) did not reverse the effects. In contrast to 5-HT(2C) receptor agonists, the antiallodynic effects of intrathecally administered alpha-m-5-HT (30 microg) and DOI (100 microg) were reversed by ketanserin, but not by RS-102221. These results indicate that 5-HT(2C) receptors have a role in spinal inhibition of neuropathic pain, and the effects produced by intrathecal administration of 5-HT(2C) receptor agonists are mediated by a mechanism different from that of alpha-m-5-HT or DOI, which seem to produce their effects through 5-HT(2A) receptors.
-
Wrist and ankle fractures are the most frequent causes of complex regional pain syndrome (CRPS type I). The current study examined the temporal development of vascular, nociceptive and bony changes after distal tibial fracture in rats and compared these changes to those observed after cast immobilization in intact normal rats. After baseline testing the right distal tibial was fractured and the hindlimb casted. ⋯ Postulating that facilitated substance P signaling may also contribute to the vascular and nociceptive abnormalities observed after tibial fracture or cast immobilization, we attempted to reverse these changes with LY303870. Hindpaw warmth, spontaneous extravasation, edema, and allodynia were inhibited by LY303870. Collectively, these data support the hypotheses that the distal tibial fracture model simulates CRPS, immobilization alone can generate a syndrome resembling CRPS, and substance P signaling contributes to the vascular and nociceptive changes observed in these models.
-
Randomized Controlled Trial Clinical Trial
Safety and efficacy of intranasal ketamine for the treatment of breakthrough pain in patients with chronic pain: a randomized, double-blind, placebo-controlled, crossover study.
Few placebo-controlled trials have investigated the treatment of breakthrough pain (BTP) in patients with chronic pain. We evaluated the efficacy and safety of intranasal ketamine for BTP in a randomized, double-blind, placebo-controlled, crossover trial. Twenty patients with chronic pain and at least two spontaneous BTP episodes daily self-administered up to five doses of intranasal ketamine or placebo at the onset of a spontaneous BTP episode (pain intensity > or =5 on a 0-10 scale). ⋯ After ketamine administration, four patients reported a transient change in taste, one patient reported rhinorrhea, one patient reported nasal passage irritation, and two patients experienced transient elevation in blood pressure. A side effect questionnaire administered 60 min and 24 h after drug or placebo administration elicited no reports of auditory or visual hallucinations. These data suggest that intranasal administration of ketamine provides rapid, safe and effective relief for BTP.
-
Randomized Controlled Trial Comparative Study Clinical Trial
Pain reducing effect of three types of transcutaneous electrical nerve stimulation in patients with chronic pain: a randomized crossover trial.
Transcutaneous electrical nerve stimulation (TENS) is a frequently applied therapy in chronic pain although evidence for effectiveness is inconclusive. Several types of TENS, based on different combinations of frequency, pulse duration and intensity, exist. The precise mechanism of action and the relevance of combinations of stimulus parameters are still unclear. ⋯ At 6 months, 42% of all patients still used TENS. We concluded that there were no differences in effectiveness for the three types of TENS used in this study. Because no placebo group was included, no definite conclusions on effectiveness of TENS in general in the treatment of chronic pain could be made.