miércoles, 11 de enero de 2017

Metamizol / Metamizole

Enero 11, 2017. No. 2566

Eventos adversos asociados al metamizol. Revisión sistemática y meta-análisis
Metamizole-associated adverse events: a systematic review and meta-analysis.
PLoS One. 2015 Apr 13;10(4):e0122918. doi: 10.1371/journal.pone.0122918. eCollection 2015.
BACKGROUND: Metamizole is used to treat pain in many parts of the world. Information on the safety profile of metamizole is scarce; no conclusive summary of the literature exists. OBJECTIVE: To determine whether metamizole is clinically safe compared to placebo and other analgesics. METHODS: We searched CENTRAL, MEDLINE, EMBASE, CINAHL, and several clinical trial registries. We screened the reference lists of included trials and previous systematic reviews. We included randomized controlled trials that compared the effects of metamizole, administered to adults in any form and for any indication, to other analgesics or to placebo. Two authors extracted data regarding trial design and size, indications for pain medication, patient characteristics, treatment regimens, and methodological characteristics. Adverse events (AEs), serious adverse events (SAEs), and dropouts were assessed. We conducted separate meta-analyses for each metamizole comparator, using standard inverse-variance random effects meta-analysis to pool the estimates across trials, reported as risk ratios (RRs). We calculated the DerSimonian and Laird variance estimate T2 to measure heterogeneity between trials. The pre-specified primary end point was any AE during the trial period. RESULTS: Of the 696 potentially eligible trials, 79 trials including almost 4000 patients with short-term metamizole use of less than two weeks met our inclusion criteria. Fewer AEs were reported for metamizole compared to opioids, RR = 0.79 (confidence interval 0.79 to 0.96). We found no differences between metamizole and placebo, paracetamol and NSAIDs. Only a few SAEs were reported, with no difference between metamizole and other analgesics. No agranulocytosis or deaths were reported. Our results were limited by the mediocre overall quality of the reports. CONCLUSION: For short-term use in the hospital setting, metamizole seems to be a safe choice when compared to other widely used analgesics. High-quality, adequately sized trials assessing the intermediate- and long-term safety of metamizole are needed.
Dosis única de dipirona para dolor postoperatorio agudo
Single dose dipyrone for acute postoperative pain.
Cochrane Database Syst Rev. 2010 Sep 8;(9):CD003227. doi: 10.1002/14651858.CD003227.pub2.
BACKGROUND: Dipyrone (metamizole) is a non-steroidal anti-inflammatory drug used in some countries to treat pain (postoperative, colic, cancer, and migraine); it is banned in others because of an association with life-threatening blood agranulocytosis. This review updates a 2001 Cochrane review, and no relevant new studies were identified, but additional outcomes were sought. OBJECTIVES: To assess the efficacy and adverse events of single dose dipyrone in acute postoperative pain. SEARCH STRATEGY: The earlier review searched CENTRAL, MEDLINE, EMBASE, LILACS and the Oxford Pain Relief Database to December 1999. For the update we searched CENTRAL, MEDLINE,EMBASE and LILACS to February 2010.
SELECTION CRITERIA: Single dose, randomised, double-blind, placebo or active controlled trials of dipyrone for relief of established moderate to severe postoperative pain in adults. We included oral, rectal, intramuscular or intravenous administration of study drugs. DATA COLLECTION AND ANALYSIS: Studies were assessed for methodological quality and data extracted by two review authors independently. Summed total pain relief over six hours (TOTPAR) was used to calculate the number of participants achieving at least 50% pain relief. Derived results were used to calculate, with 95% confidence intervals, relative benefit compared to placebo, and the number needed to treat (NNT) for one participant to experience at least 50% pain relief over six hours. Use and time to use of rescue medication were additional measures of efficacy. Information on adverse events and withdrawals was collected. MAIN RESULTS: Fifteen studies tested mainly 500 mg oral dipyrone (173 participants), 2.5 g intravenous dipyrone (101), 2.5 g intramuscular dipyrone (99); fewer than 60 participants received any other dose. All studies used active controls (ibuprofen, paracetamol, aspirin, flurbiprofen, ketoprofen, dexketoprofen, ketorolac, pethidine, tramadol, suprofen); eight used placebo controls.Over 70% of participants experienced at least 50% pain relief over 4 to 6 hours with oral dipyrone 500 mg compared to 30% with placebo in five studies (288 participants; NNT 2.4 (1.9 to 3.2)). Fewer participants needed rescue medication with dipyrone (7%) than with placebo (34%; four studies, 248 participants). There was no difference in participants experiencing at least 50% pain relief with 2.5 g intravenous dipyrone and 100 mg intravenous tramadol (70% vs 65%; two studies, 200 participants). No serious adverse events were reported.
AUTHORS' CONCLUSIONS: Based on very limited information, single dose dipyrone 500 mg provides good pain relief to 70% of patients. For every five individuals given dipyrone 500 mg, two would experience this level of pain relief who would not have done with placebo, and fewer would need rescue medication, over 4 to 6 hours.

Metamizol/dipirona para el alivio de dolor por cáncer. Revisión sistemática y recomendaciones basadas en evidencias para la práctica clínica
Metamizole/dipyrone for the relief of cancer pain: A systematic review and evidence-based recommendations for clinical practice.
Palliat Med. 2017 Jan;31(1):26-34. doi: 10.1177/0269216316655746. Epub 2016 Jul 20.
BACKGROUND: Dipyrone (metamizole) is one of the most widely used non-opioid analgesics for the treatment of cancer pain. AIM: Because evidence-based recommendations are not yet available, a systematic review was conducted for the German Guideline Program in Oncology to provide recommendations for the use of dipyrone in cancer pain. DESIGN: First, a systematic review for clinical trials assessing dipyrone in adult patients with cancer pain was conducted. Endpoints were pain intensity, opioid-sparing effects, safety, and quality of life. ..... CONCLUSION: Dipyrone can be recommended for the treatment of cancer pain as an alternative to other non-opioids either alone or in combination with opioids. It can be preferred over non-steroidal anti-inflammatory drugs due to the presumably favorable side effect profile in long-term use, but comparative studies are not available for long-term use.
KEYWORDS: Dipyrone; neoplasms; non-steroidal anti-inflammatory agents; pain management; palliative care; review

Efectos de los alimentos sobre la farmacocinética de formulaciones de liberación rápida de aspirina, dipirona, paracetamol y AINES. Revisión sistemática
Effects of food on pharmacokinetics of immediate release oral formulations of aspirin, dipyrone, paracetamol and NSAIDs - a systematic review.
Br J Clin Pharmacol. 2015 Sep;80(3):381-8. doi: 10.1111/bcp.12628. Epub 2015 Jul 6.
AIMS: It is common to advise that analgesics, and especially non-steroidal anti-inflammatory drugs (NSAIDs), be taken with food to reduce unwanted gastrointestinal adverse effects. The efficacy of single dose analgesics depends on producing high, early, plasma concentrations; food may interfere with this. This review sought evidence from single dose pharmacokinetic studies on the extent and timing of peak plasma concentrations of analgesic drugs in the fed and fasting states..... CONCLUSION: There is evidence that high, early plasma concentrations produces better early pain relief, better overall pain relief, longer lasting pain relief and lower rates of remedication. Taking analgesics with food may make them less effective, resulting in greater population exposure. It may be time to rethink research priorities and advice to professionals, patients and the public.
KEYWORDS: analgesic; bioavailability; food; maximum plasma concentration; oral; pharmacokinetic
Metamizol versus ibuprofeno en casa después de cirugía ambulatoria. Protocolo de estudio randomizado controlado
Metamizole versus ibuprofen at home after day surgery: study protocol for a randomised controlled trial.
BACKGROUND: Postoperative pain and, in a more extended perspective, quality of recovery (QOR) should be considered the principal endpoints after day surgery. Non-steroidal anti-inflammatory drugs (NSAIDs) and paracetamol are a cornerstone of pain treatment after painful day surgery. Nevertheless, NSAIDs are not always sufficiently effective, have numerous contraindications, and consequently are not suitable in up to 25 % of all patients. Metamizole is a non-opioid compound with a favourable gastrointestinal, cardiovascular and cerebrovascular profile compared to NSAIDs. The aim of this study is to assess if a combination of metamizole and paracetamol is non-inferior to a combination of ibuprofen and paracetamol in the treatment of acute postoperative pain at home after painful day case surgery. In addition, we aim to assess and compare quality of recovery (QOR) profiles of both groups. METHODS/DESIGN: This is an investigator-initiated, double-blind, randomised controlled, non-inferiority trial. A total of 200 patients undergoing elective haemorrhoid surgery, arthroscopic shoulder or knee surgery, or inguinal hernia repair in a day care setting will be randomised to receive either a combination of metamizole and paracetamol (MP) or a combination of ibuprofen and paracetamol (IP). Participants will take study medication orally for 4 days. Primary endpoints are average postoperative pain intensity measured by an 11-point Numeric Rating Scale at postoperative day 1 and QOR profile measured by the Functional Recovery Index (FRI), the 1-item Global Surgical Recovery (GSR) index and the EuroQol (EQ-5D) questionnaire at days 1, 2, 3, 4, 7, 14 and 28 postoperatively. Secondary outcomes include compliance with study medication, adverse effects of study medication, use of rescue medication and satisfaction with study medication, surgery and hospital care and telephone follow-up. DISCUSSION: This study will provide clinical evidence on the analgesic efficacy and safety of a combination of metamizole and paracetamol in treating postoperative pain at home after painful day surgery. This study may also provide an insight into QOR profile after four different types of surgery and into the interrelationship between three different instruments used to assess QOR.
KEYWORDS: Acute pain; Ambulatory surgery; Day surgery; Dipyrone; EQ-5D; Functional Recovery Index; Metamizole; NSAID; Postoperative pain; Recovery

Neutropenia, agranulocitosis y dipirona
Neutropenia, agranulocytosis and dipyrone.
Sao Paulo Med J. 2005 Sep 1;123(5):247-9. Epub 2005 Dec 8.
CONTEXT: Neutropenia and agranulocytosis may be defined as granulocyte counts of less than 1,500/mm3 and 500/mm3, respectively. Agranulocytosis is a rare and serious disease often caused by drugs. Its mortality rate is around 10%. The most common manifestations are infections such as tonsillitis, pharyngitis, stomatitis or pneumonia. Although dipyrone is one of the drugs known to be associated with agranulocytosis, the strength of the association has been a matter of much debate. Moreover, alternative analgesic and antipyretic agents are not devoid of serious side effects. CONCLUSIONS: It is therefore necessary to establish the incidence of agranulocytosis in Latin America and the role of dipyrone. The ongoing LATIN Study is a multicenter international case-control study that will provide answers for these questions.
Regional Anesthesiology and Acute Pain Medicine Meeting
April 6-8, 2017, San Francisco, California, USA
ASRA American Society of Regional Anesthesia and Pain Medicine
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