Pregabalin for chronic pain: does one medication fit all?

BACKGROUND: Pregabalin is frequently prescribed for chronic non-cancer pain. No previous study has examined its off-label use. OBJECTIVES: Our primary aim was to assess the proportion of patients taking pregabalin for conditions approved by Health Canada ('on-label') and compare their perspectives on its use to those who use pregabalin for other conditions ('off-label'). METHODS: Patients who have used pregabalin within the past year were recruited from two registries of chronic non-cancer pain patients treated in tertiary care clinics: the Quebec Pain Registry and the Fibromyalgia Patients Registry. Data on the use of pregabalin and its perceived benefits were collected from the registries and from completed questionnaires. RESULTS: Out of 4339 screened chronic non-cancer pain patients, 355 (8.18%) met the study selection criteria. Three-quarters of them (268/355) used pregabalin for pain conditions not approved by Health Canada and were therefore regarded as off-label users. The most prevalent condition for pregabalin use was lumbar back pain (103/357; 28.85%). There were no significant differences between on- and off-label users in their perceived satisfaction from pregabalin therapy and its effect on function and quality of life. Among former users, the most prevalent reason for discontinuation was adverse effects, mainly dry mouth and weight gain. CONCLUSIONS: We conclude that despite specific indications for pregabalin prescription, it is mainly used off-label, notably for low back pain. Nevertheless, off-label users were equally satisfied with its clinical effects. Although formal exploration of the broader analgesic properties of pregabalin is warranted, treating heterogeneous chronic pain conditions with pregabalin may be legitimate. LIMITATIONS: The main limitations of the study are patients' low response rate, the recruitment of participants solely from a tertiary pain center and not from the general patient population and a possible recall bias that may have arisen from the retrospective nature of the study.

Rates and Correlates of Unemployment Across Four Common Chronic Pain Diagnostic Categories.

PURPOSE: To examine rates and correlates of unemployment across distinct common chronic pain diagnoses. METHODS: Data were analyzed from a sample of 2,382 patients with chronic pain in the Quebec Pain Registry (QPR). Patients were grouped into the following diagnostic categories based on their primary pain diagnosis recorded in the QPR: musculoskeletal pain; myofascial pain; neuropathic pain, and visceral pain. Analyses were performed to examine the associations between pain diagnosis, patient demographics, pain intensity, depressive symptoms, and unemployment status. RESULTS: Pain diagnosis, age, marital status, education, pain intensity, and depressive symptoms were each significant unique predictors of unemployment status in a hierarchical logistic regression analysis; the addition of depressive symptoms in this model contributed to the greatest increment of model fit. CONCLUSIONS: Depressive symptoms are associated with unemployment across a number of common chronic pain conditions, even when controlling for other factors that are associated with unemployment in these patients. Depressive symptoms, as a modifiable factor, may thus be an important target of intervention for unemployed patients with chronic pain.

Intradialytic clearance of opioids: methadone versus hydromorphone.

Opioids are commonly prescribed to patients with chronic pain associated with end-stage renal disease requiring hemodialysis. The stability of opioid analgesia during dialysis may vary among different opioids. No studies to date have corroborated this clinical observation by directly comparing plasma concentrations of different opioids during dialysis. We compared changes in peridialysis plasma concentrations of 2 pharmacokinetically distinct opioids, methadone and hydromorphone (HM). Fourteen dialysis patients with chronic pain received either methadone or HM for at least 2 weeks before beginning the study. Blood samples were obtained immediately before, during, and after hemodialysis in 2 separate dialysis sessions, 1 week apart, and were analyzed for opioid concentrations. Methadone plasma concentrations were more stable during hemodialysis compared to HM: the mean percent change of methadone plasma levels was 14.9% ± 8.2% (± SD) compared with 55.1% ± 8.1% in the HM treatment group, a difference of 40.2% (95% confidence interval 17.14 to 63.14). The mean plasma clearance of methadone was 19.9 ± 8.5 mL/min (± SD) compared with 105.7 ± 8.3 mL/min for HM, a difference of 85.7 mL/min (95% confidence interval 61.9 to 109.1). There were no differences between the 2 opioid groups in pain scores, side effect profile, and quality of life. Methadone therapy was not associated with an increased rate of adverse events. If confirmed by larger clinical studies, methadone could be considered as one of the opioids of choice in dialysis patients.

A rare complication of infective endocarditis: left main coronary artery embolization resulting in sudden death.

Whilst systemic septic embolization is a common complication of infective endocarditis, a second, less frequently reported, complication is the embolization of vegetative material to the coronary arteries that rarely results in acute myocardial infarction and sudden death. The case is presented of an acute cardiac death in a patient with aortic valve endocarditis, caused by acute occlusion of the left main coronary artery with vegetative material.

A rare case of enterobacter endocarditis superimposed on a mitral valve rheumatoid nodule.

We present the case of a 56-year-old man with longstanding seropositive active erosive and deforming rheumatoid arthritis with no peripheral rheumatoid nodules; he immigrated from the former Soviet Union (where he did not receive any disease-modifying antirheumatic drugs) to Israel in 1995. In February 2005, he had a buccogingival mucosal abscess on his lower lip, which was treated by surgical drainage, followed by prolonged antibiotic therapy. One and a half years later, he had 2 episodes of transient ischemic attacks characterized by speech difficulties and moderate weakness on his right side. Transesophageal echocardiogram revealed a mass on the anterior mitral valve leaflet. Repeated blood cultures were negative, and the patient was afebrile all the time. The patient underwent mitral valve replacement and the histologic findings of the mass were typical of both a rheumatoid nodule and bacterial endocarditis. The patient recovered fully after 6 weeks of antibiotic therapy. Emboli from a rheumatoid nodule should always be considered in patients with rheumatoid arthritis who present with transient ischemic attacks.

Analysis of RNA decay, processing, and polyadenylation in Escherichia coli and other prokaryotes.

This chapter provides detailed methodologies for isolating total RNA and polyadenylated RNA from E. coli and other prokaryotes, along with the procedures necessary to analyze the processing and decay of specific transcripts and determine their 3'- and 5'-ends. The RNA isolation methods described here facilitate isolating good-quality RNA in a very cost-effective way compared to the commercially available RNA isolation kits, without employing phenol and/or alcohol precipitation. We also discuss the limits associated with polyacrylamide and agarose gels for the separation of small and large RNAs. Methods useful for the analysis of post-transcriptionally modified transcripts and the processing of very large polycistronic transcripts are also presented.