Pain
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The analgesic effectiveness and safety of oral tramadol were compared with standard analgesics using a meta-analysis of individual patient data from randomised controlled trials in patients with moderate or severe pain after surgery or dental extraction. Calculation of %maxTOTPAR from individual patient data, and the use of > 50%maxTOTPAR defined clinically acceptable pain relief. Number-needed-to-treat (NNT) for one patient to have > 50%maxTOTPAR compared with placebo was used to examine the effectiveness of different single oral doses of tramadol and comparator drugs. ⋯ There was a dose response with tramadol, tending towards higher incidences at higher doses. Single-patient meta-analysis using more than half pain relief provides a sensitive description of the analgesic properties of a drug, and NNT calculations allow comparisons to be made with standard analgesics. Absolute ranking of analgesic performance should be done separately for postsurgical and dental pain.
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Randomized Controlled Trial Clinical Trial
Pharmacokinetics and pharmacodynamics of twenty-four-hourly Kapanol compared to twelve-hourly MS Contin in the treatment of severe cancer pain.
Twenty-four patients with severe pain related to cancer completed a randomised, double-blind, double-dummy, crossover study examining morphine pharmacokinetics and pharmacodynamics when the same 24-h morphine dose was administered using two modified release oral morphine formulations; either one dose of Kapanol (a new sustained release polymer coated pellet formulation administered in capsule form, Glaxo Wellcome group of companies) per 24 h, or MS Contin (Purdue Frederick Company, Connecticut, USA) administered at 12-h intervals. The morphine dose was optimised for each patient using an immediate release morphine solution in the lead-in period to provide the most favourable balance between pain relief and side-effects. Patients were then randomly allocated to receive their 24-h morphine dose as either Kapanol or MS Contin in period 1. ⋯ Some of these pharmacokinetic differences (e.g., Cmin and fluctuation in plasma morphine concentration) were surprising given that the dosing interval for Kapanol (24 h) was double that of MS Contin (12 h). There was no significant difference between the Kapanol and MS Contin treatment phases in any of the pharmacodynamic parameters, morphine related side-effects, the percentage of patients taking rescue medication as well as the amount or time to the first dose of rescue analgesia on day 7 in periods 1 and 2, patient or investigator assessments of global efficacy at the end of periods 1 and 2, or patient treatment preference at the end of the study. Once a day Kapanol provided the same degree of pain relief and morphine related side-effects as 12-h MS Contin.
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The aim of this study was to examine whether mean data from categorical pain intensity and visual analogue scales for both pain intensity and relief could be used reliably to derive dichotomous outcome measures for meta-analysis. Individual patient data from randomised controlled trials of single-dose analgesics in acute postoperative pain were used. The methods used were as follows: data from 132 treatments with over 4700 patients were used to calculate mean %maxSPID (categorical pain intensity), %maxVAS-SPID (visual analogue pain intensity) and %maxVAS-TOTPAR (visual analogue pain relief); these were used to derive relationships with the number of patients who achieved at least 50% pain relief (%maxTOTPAR). ⋯ Reports of randomised trials of analgesics frequently describe results of studies in the form of mean derived indices, rather than using discontinuous events, such as number of proportion of patients obtaining at least 50% pain relief. Because mean data inadequately describe information with a non-normal distribution, combining such mean data in systematic reviews may compromise the results. Showing that dichotomous data can reliably be derived from mean SPID, VAS-SPID and VAS-TOTPAR as well as TOTPAR data in previously published acute pain studies makes much more information accessible for meta-analysis.
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Two studies that assess fear and avoidance in patients with chronic pain are presented. In the first study, 200 patients with chronic back pain were classified, using the Multidimensional Pain Inventory (Kerns et al., 1985) clustering procedure, as dysfunctional (n = 53), interpersonally distressed (n = 37), and adaptive copers (n = 62). Groups were compared on common measures of anxiety, fear and avoidance. ⋯ In the second study, pain-specific fear and avoidance measures were used in a discriminant function analysis to predict the MPI classification of an independent sample of 55 patients with chronic pain. The measures correctly classified 76.5% of the dysfunctional group and 71.1% of a composite group of interpersonally distressed and adaptive copers. The implications of these findings are discussed.
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Duration of acute herpetic pain (AHP) in 1431 patients for whom treatment was begun within 14 days after the onset of herpes zoster (HZ) was analyzed with respect to age, involved region, and severity of skin lesions. All patients were treated with repeated sympathetic nerve blocks until their pain was almost nil. Severity of the skin lesions at the worst phase was defined as mild when they covered less than one-quarter of the primary dermatome, as severe when they covered more than three-quarters of the primary dermatome, and moderate if they were between mild and severe. ⋯ Multiple stepwise regression analysis revealed that the most important factors influencing the duration of AHP were the severity of skin lesions of HZ at the worst phase (r = 0.412), age (r = 0.277) and the involved region (r = -0.101). Thus, AHP in the elderly and in cases of trigeminal involvement is longer because of higher frequencies of severe HZ in the elderly and in trigeminal involvement rather than "being aged' and "trigeminal involvement' itself. We propose that one needs to analyze the results of treatment of AHP with respect to the severity of skin lesions at the worst phase.