Pain
-
Randomized Controlled Trial Clinical Trial
Lack of analgesic efficacy of oral delta-9-tetrahydrocannabinol in postoperative pain.
We have evaluated the efficacy of delta-9-tetrahydrocannabinol (delta-9-THC), the main psychoactive constituent of cannabis, in postoperative pain. In a randomized double-blind, placebo-controlled, single-dose trial, we investigated 40 women undergoing elective abdominal hysterectomy. Randomization took place when postoperative patient-controlled analgesia was discontinued on the second postoperative day. ⋯ Increased awareness of surroundings was reported more frequently in patients receiving delta-9-THC (40 vs 5%, P=0.04). There were no other significant differences with respect to adverse events. This study demonstrates no evidence of an analgesic effect of orally administered delta-9-THC 5 mg in postoperative pain in humans.
-
Emotions have been shown to alter pain perception, but the underlying mechanism is unclear since emotions also affect attention, which itself changes nociceptive transmission. We manipulated independently direction of attention and emotional state, using tasks involving heat pain and pleasant and unpleasant odors. Shifts in attention between the thermal and olfactory modalities did not alter mood or anxiety. ⋯ In contrast, odor valence altered mood, anxiety level, and pain unpleasantness, but did not change the perception of pain intensity. Pain unpleasantness ratings correlated with mood, but not with odor valence, suggesting that emotional changes underlie the selective modulation of pain affect. These results show that emotion and attention differentially alter pain perception and thus invoke at least partially separable neural modulatory circuits.
-
This paper reports upon: (1) the value of acceptance of pain in predicting well-being in patients suffering from chronic pain and (2) the construct validity of acceptance by comparing two questionnaires designed to measure acceptance (the Chronic Pain Acceptance Questionnaire, CPAQ, unpublished doctoral dissertation, University of Nevada, Reno, NV, 1992 and the Illness Cognitions Questionnaire, ICQ, J Consult Clin Psychol 69 (2001) 1026). The results of two independent cross-sectional studies are reported. Study 1 included 120 patients seeking help in tertiary care settings. ⋯ Acceptance in both instruments was strongly related to a cognitive control over pain. Study 2 further revealed that the correlation between the CPAQ and the ICQ is moderate, indicating that both instruments measured different aspects of acceptance. It is concluded that acceptance of chronic pain is best conceived of as the shift away from pain to non-pain aspects of life, and the shift away from a search for a cure with an acknowledgement that pain may not change.
-
The objective of this study was to adapt the concept of 'episode-free day', a metric for measuring symptom relief in daily units, to the clinical outcome literature for persistent pain. The episode-free day metric is widely used in other medical literature, but no analogous measure exists in pain literature. Prior focus groups with this population suggested that a 'Day of Manageable Pain Control' was an appropriate name for the metric. ⋯ For both patient samples, '5' was the cut-point that optimally distinguished groups on pain-related interference. '5-8' and '5-7' were double cut-point solutions that optimally divided LBP and OA samples into three categories (e.g. lowest, medium and highest average pain), respectively. Derived cut-points were confirmed using a variety of measures of functional disability. Together with research that showed that average pain ratings of approximately 5 and below permit increased function and quality of life in patients with moderate to severe low back pain and osteoarthritis, our findings provide support for the use of 0-5 on a 0-10 numeric average pain severity scale as one possible criterion for a Manageable Day.
-
Randomized Controlled Trial Multicenter Study Clinical Trial
Efficacy of lidocaine patch 5% in the treatment of focal peripheral neuropathic pain syndromes: a randomized, double-blind, placebo-controlled study.
Peripheral neuropathic pain syndromes (PNPS) are difficult to treat because commonly used analgesics are often ineffective when, for example, touch-evoked allodynia, hyperalgesia, and pain paroxysms are present. To investigate whether lidocaine patch 5% treatment is also effective in postherpetic neuropathy (PHN) and in other PNPS, 40 patients with various forms and localizations of PNPS completed a prospective, randomized, placebo-controlled, two-way, cross-over study in three medical hospitals. Patients suffering from pain in a localized skin area with intensity above 40 mm visual analog scale (VAS) and a stable consumption of pain medication were included in this study. ⋯ When, after the wash-out period, the pain intensity scores did not return to the pre-treatment values (+/-20%), these patients were excluded from the study. The present study revealed that, as an add-on therapy, the lidocaine patch 5% was clearly effective in reducing ongoing pain (P=0.017) and allodynia (P=0.023) during the first 8 h after application and that the patches also worked well over a period of 7 days (P=0.018) in diverse focal PNPS. Calculation of the numbers needed to treat (NNT) to obtain one patient with more than 50% relief of ongoing pain revealed that the NNT of 4.4 in the present study compared reasonably well with other studies of PHN, such as topically applied capsaicin (NNT: 5.3-infinity) or systemic treatment with gabapentin (NNT: 3.2-5.0).