Pain
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Randomized Controlled Trial Clinical Trial
A placebo-controlled randomized clinical trial of nortriptyline for chronic low back pain.
To assess the efficacy of nortriptyline, a tricyclic antidepressant, as an analgesic in chronic back pain without depression, we conducted a randomized, double-blind, placebo-controlled, 8-week trial in 78 men recruited from primary care and general orthopedic settings, who had chronic low back pain (pain at T-6 or below on a daily basis for 6 months or longer). Of these 57 completed the trial; of the 21 who did not complete, four were withdrawn because of adverse effects. The intervention consisted of inert placebo or nortriptyline titrated to within the therapeutic range for treating major depression (50-150 ng/ml). ⋯ Also, completers with radicular pain on nortriptyline (n = 5) had significantly (P < 0.05) better analgesia and overall outcome than did those on placebo (n = 6). The results suggest noradrenergic mechanisms are relevant to analgesia in back pain. This modest reduction in pain intensity suggests that physicians should carefully weigh the risks and benefits of nortriptyline in chronic back pain without depression.
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Randomized Controlled Trial Clinical Trial
Effects of antihyperalgesic drugs on experimentally induced hyperalgesia in man.
In a double-blind, cross-over study, ibuprofen (600 mg), a peripherally-acting selective kappa-opioid receptor agonist (7.5 mg), or placebo were given orally in experiments on healthy volunteers 1 h before assessment of pain thresholds to radiant heat and of pain ratings to controlled mechanical impact stimuli. Mechanical and thermal hyperalgesia had been induced 24 h before by irradiating skin patches on the ventral side of the upper leg. UVB irradiation induced mechanical and thermal hyperalgesia at radiation dosages of three times the minimal erythema dose. ⋯ In contrast, the kappa-agonist showed no antihyperalgesic efficacy in the chosen models. It is concluded that the UVB model, as the pinch model, is suitable for establishing antihyperalgesic effects of NSAIDs, but probably not of kappa-receptor agonists, in healthy human volunteers. Compared to the pinch stimulus model, the UVB model offers additional advantages: (a) drugs may be tested after induction of the skin trauma by UV and this situation is more similar to the clinical use of antihyperalgesic drugs. (b) Since mechanical and thermal hyperalgesia is induced by UVB, drug effects can be tested upon both forms of hyperalgesia.
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Clinical Trial
Bedside application of the Neonatal Facial Coding System in pain assessment of premature neonates.
Assessment of infant pain is a pressing concern, especially within the context of neonatal intensive care where infants may be exposed to prolonged and repeated pain during lengthy hospitalization. In the present study the feasibility of carrying out the complete Neonatal Facial Coding System (NFCS) in real time at bedside, specifically reliability, construct and concurrent validity, was evaluated in a tertiary level Neonatal Intensive Care Unit (NICU). Heel lance was used as a model of procedural pain, and observed with n = 40 infants at 32 weeks gestational age. ⋯ Inter-observer reliability was high. Construct validity of the NFCS at bedside was demonstrated as invasive procedures were distinguished from tactile. While bedside coding of behavior does not permit raters to be blind to events, mechanical recording of heart rate allowed for an independent source of concurrent validation for bedside application of the NFCS scale.
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The aim of the study was to examine the presence of hyperalgesia to heat stimuli within the zone of secondary hyperalgesia to punctate mechanical stimuli. A burn was produced on the medial part of the non-dominant crus in 15 healthy volunteers with a 50 x 25 mm thermode (47 degrees C, 7 min), and assessments were made 70 min and 40 min before, and 0, 1, and 2 h after the burn injury. Hyperalgesia to mechanical and heat stimuli were examined by von Frey hairs and contact thermodes (3.75 and 12.5 cm2), and pain responses were rated with a visual analog scale (0-100). ⋯ Further, the heat pain response was more intense in the zone of primary hyperalgesia than in the zone of secondary hyperalgesia (P = 0.004), in contrast to the mechanical pain response, which was not significantly different between the two zones of hyperalgesia. In conclusion, secondary hyperalgesia in man is not restricted to mechanical stimuli, as significant hyperalgesia to heat developed within the zone of secondary hyperalgesia to punctate mechanical stimuli. The data, combined with other evidence, suggest differences in the mechanisms accounting for primary hyperalgesia to heat and mechanical stimuli, whereas secondary hyperalgesia to heat and mechanical stimuli may be explained by a common central mechanism.
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Randomized Controlled Trial Comparative Study Clinical Trial
The influence of film-induced mood on pain perception.
It has been shown that a person's mood can influence pain tolerance. Films have been used as a means of inducing a desired mood. The effect on pain perception of film type and film length to induce mood was investigated. ⋯ Each subject was given a baseline trial of cold-pressor pain, a trial immediately following the film and a trial 30 min later. Results indicated an advantage in increased pain tolerance for the humorous film and an increased pain tolerance for the longer film regardless of type only after the 30-min waiting period. Results were discussed from a pain theoretical perspective with emphasis placed on returning to psychological manipulations of the sensory aspects of pain and not just the cognitive/emotional/motivational dimensions.