Utilization pattern of metamizole in northern Sweden and risk estimates of agranulocytosis

A Case Report on Metamizole-Induced Agranulocytosis: Is the Benefit Worth the Risk?

Metamizole is a drug with analgesic and antipyretic properties widely available in Portugal. Its use is highly controversial because of the risk of agranulocytosis, a rare but serious adverse event. A 70-year-old female patient with a recent history of treatment with metamizole for post-surgery fever and pain presented to the ED with sustained fever, diarrhea, and painful mouth ulcers. Laboratory tests revealed agranulocytosis. The patient was placed under protective isolation and started treatment with granulocyte-colony stimulating factor (G-CSF) and empiric antibiotic therapy with piperacillin/tazobactam and vancomycin for neutropenic fever. After an extensive workup, no source of infection was identified. During hospitalization, infectious and neoplastic causes of agranulocytosis were investigated, but the results were negative. Metamizole-induced agranulocytosis was suspected. The patient completed a total of three days of G-CSF and eight days of empiric antibiotic therapy with sustained clinical improvement. She was discharged completely asymptomatic and remained clinically stable during follow-up without a resurgence of agranulocytosis. This case report is intended to increase awareness of metamizole-induced agranulocytosis. While this is a well-known side effect, it is also often overlooked. It is paramount that both physicians and patients know how to correctly manage metamizole to prevent and promptly treat agranulocytosis.

[Adequacy of the safety of metamizole and agranulocytosis]

Objetivo

Analizar si la nota informativa de la Agencia Española de Medicamentos y Productos Sanitarios (AEMPS), de 30 de octubre del 2018, sobre agranulocitosis y metamizol contiene la información precisa y necesaria para proteger a los pacientes de la aparición de esta reacción adversa (RA) y si la documentación oficial de los medicamentos con metamizol para médicos, farmacéuticos y población general está adaptada a las directrices de la AEMPS para disminuir el riesgo.

Emplazamiento y participantes

Nota informativa, búsqueda bibliográfica, información sobre los medicamentos con metamizol comercializados en España en la Agencia Europea del Medicamento, fichas técnicas, prospectos, base de datos de información sanitaria Bot PLUS y Catálogo de Especialidades Farmacéuticas. Notificación de 4 casos de agranulocitosis por metamizol posteriores a la fecha de la nota informativa.

Intervenciones y mediciones principales

Comparación de los puntos clave de la nota informativa y de los documentos oficiales sobre metamizol con la bibliografía. Descripción de 4 casos de agranulocitosis por metamizol y aplicación del algoritmo de causalidad y gravedad.

Resultados

La nota informativa presenta ausencias y dudas respecto a la bibliografía y al uso de metamizol en la práctica asistencial. Los documentos oficiales presentan faltas de actualización, indicaciones no aprobadas y dosis superiores a las recomendadas. La nota informativa no ha frenado la presentación de casos de agranulocitosis por metamizol.

Conclusiones

La nota informativa de la AEMPS es mejorable y es necesario actualizar los documentos oficiales de información sobre el metamizol para profesionales sanitarios y pacientes para disminuir el riesgo de agranulocitosis.

Paediatric Agranulocytosis Associated with Metamizole Treatment

PURPOSE

Metamizole, which has antipyretic and pain-relieving properties, is generally used to treat fever in children who do not respond to paracetamol treatment. The most remarkable side effect of metamizole is that it causes myelotoxicity independently of dose. In this study, we aimed to present the clinical features of paediatric patients who developed agranulocytosis after the use of metamizole and draw attention to this side effect.

METHODS

The patients who were admitted to Eskişehir Osmangazi University Faculty of Medicine Hospital, Pediatric Infectious Diseases and Pediatric Hematology Service, between January 1, 2015, and December 31, 2018, with a diagnosis of secondary agranulocytosis to metamizole use were examined retrospectively.

RESULTS

In all, 12 patients were included in the study; oral metamizole was used in these patients for fever reduction. The mean absolute neutrophil count was 225/mm³ ± 226 (0-600/mm³) at admission, and the neutrophil value of 11 patients was < 500/mm³. The mean length of hospitalisation of the patients was 9.92 ± 8 (3-28) days. Eight patients received intravenous antibiotic therapy and four patients received at least one of the following treatments: intravenous immunoglobulin, granulocyte colony-stimulating factor and methylprednisolone. Bone marrow aspiration examination showed neutrophil/band maturation delaying in the myeloid series with normocellular bone marrow in three patients. Hypocellularity in the bone marrow and decrease in myeloid precursors were observed in three patients. There were no fatal cases.

CONCLUSION

The development of agranulocytosis after the use of metamizole causes long-term hospitalisation and may require the use of medications in treatment management. Considering the availability of alternative options to treat fever and pain, and given the side-effect profile of metamizole, it should not be the preferred, first-line antipyretic treatment in children.

Regional Differences in Prescribing Patterns of Metamizole in Germany Based on Data from 70 Million Persons

The non-opioid analgesic metamizole (dipyrone) is commonly used in Germany despite its narrow indications and market withdrawal from several countries. In this study we analyzed prescribing patterns of metamizole focusing on regional differences. The source of data was the “Information system for health care data” which includes data from the statutory health insurance funds for about 70 million Germans. We received aggregated data of individuals with at least one metamizole prescription in 2010 as well as the number of prescribed packages by age, sex, state and district along with the number of insured persons in each stratum. We calculated prescription prevalence stratified by age, sex, state and district. Among 68.4 million insured persons (mean age: 43.6 years; 53.0% female) 5.5 million received at least one metamizole prescription (8.1%, overall 12.2 million packages). Prevalence increased with age, and women received metamizole more often than men. In adults (total prevalence: 9.4%), levels varied between 7.0% (Saxony) and 11.1% (Schleswig-Holstein), whereas on a district level use ranged from 4.3% to 14.3%. In 2010, one of 12 individuals received metamizole at least once. Noticeable were the large regional variations which certainly cannot be explained by patient-related factors.

Agranulocytosis attributed to metamizole: An analysis of spontaneous reports in EudraVigilance 1985-2017

Despite ongoing debates about its safety, the use of metamizole (dipyrone) is still increasing in many countries. In this study, we analysed spontaneous reports of suspected metamizole-associated agranulocytosis recorded in EudraVigilance database from 1985 to 2017 with regard to patient and treatment characteristics as well as fatal vs non-fatal outcomes and compared these findings among countries. A total of 1448 reports from 31 different countries were included (Germany 42.0%; Spain 29.6%; Switzerland 13.1%; other countries 15.3%). Mean age of patients was 53.6 years (63.4% females). Differences among countries were observed, for example with respect to patient age, route of administration and daily doses. Overall, median time between starting metamizole and developing an agranulocytosis was 13 days with 34.7% of cases occurring up to 7 days. This time was much shorter in patients who had already received metamizole before (median: 6 vs 15 days). About 16% of cases ended fatally. Patients with fatal outcomes were older and more often had also received methotrexate compared to those with non-fatal outcomes. When adjusting for age and sex in a multivariable logistic regression, methotrexate was associated with an increased risk of fatal outcomes (odds ratio: 5.18; 95% confidence interval: 3.06-8.78). In conclusion, metamizole-associated agranulocytosis is still a life-threatening condition, especially in the elderly and those also receiving methotrexate. As agranulocytosis can develop weeks after last administration and independently of dose and duration of treatment, prescribers and patients should be aware of its signs and symptoms.

[Current aspects of pain management during and after dermatologic surgery]

The project "Pain-free Hospital" was the first attempt to improve the level of postoperative care by standardizing pain therapy standards (concepts) in the individual surgical disciplines. Dermatosurgery is no exception. In addition to drug therapy, it is also important to consider biopsychosocial aspects of the symptom pain, as this is the only way to prevent chronification of acute pain in the further course of a disease. Drug therapy should not only be adapted to the classic WHO system (only considering pain intensity), but should also address aspects of pain quality. In this article, we discuss these aspects in more detail and present our treatment concept for dermatosurgery.

Pain-Prescription Differences - An Analysis of 500,000 Discharge Summaries

BACKGROUND

Pain-relief prescriptions have led to an alarming increase in drug-related abuse.

OBJECTIVE

In this study, we estimate the pain reliever prescription rates at a major German academic hospital center and compare with the nationwide trends from Germany and prescription reports from the USA.

METHODS

We analysed >500,000 discharge summaries from Charité, encompassing the years 2006 to 2015, and extracted the medications and diagnoses from each discharge summary. Prescription reports from the USA and Germany were collected and compared with the trends at Charité to identify the frequently prescribed pain relievers and their world-wide utilization trends. The average costs of pain therapy were also calculated and compared between the three regions.

RESULTS

Metamizole (dipyrone), a non-opioid analgesic, was the most commonly prescribed pain reliever at Charité (59%) and in Germany (23%) while oxycodone (29%), a semi-synthetic opioid, was most commonly ordered in the USA. Surprisingly, metamizole was prescribed to nearly 20% of all patients at Charité, a drug that has been banned for safety reasons (agranulocytosis) in most developed countries including Canada, United Kingdom, and USA. A large number of prospective cases with high risk for agranulocytosis and other side effects were found. The average cost of pain therapy greatly varied between the USA (125.3 EUR) and Charité (17.2 EUR).

CONCLUSION

The choice of pain relievers varies regionally and is often in disagreement with approved indications and regulatory guidelines. A pronounced East-West gradient was observed with metamizole use and the opposite with prescription opioids.

Pre- and perioperative aspects of dermatosurgery

Dermatosurgery occupies an exceptional position among all surgical disciplines. Above all, this includes the fact that, with very few exceptions, the vast majority of surgical interventions can be performed under local or regional anesthesia, usually in smaller procedure rooms that are spatially separated from larger operating suites. Thus, peri- and postinterventional patient monitoring is the responsibility of the dermatosurgeon and his team. Though inherently smaller, this team still has to observe numerous perioperative requirements that - in larger surgical specialties - would be attended to by a host of various specialists working in concert. Said requirements include hygienic aspects, knowledge concerning pre- and intraoperative patient monitoring, managing surgical site infections, adequate postsurgical pain management, as well as detailed pharmacological knowledge with respect to common local anesthetics and the toxic and allergic reactions associated therewith. Not only does this require interdisciplinary collaboration and shared responsibility for the patient. It also necessitates the development and implementation of quality-oriented and evidence-based guidelines that, in the dermatosurgical setting, usually extend far beyond the scope of the specialty per se. The objective of the present CME article is the condensed presentation of interdisciplinary aspects relating to the most important perioperative issues.

Prä- und perioperative Aspekte der Versorgung dermatochirurgischer Patienten

Die Dermatochirurgie nimmt hinsichtlich vieler Punkte eine Sonderstellung unter den operativen Fächern ein. Hierzu gehört in erster Linie die Tatsache, dass bis auf wenige Ausnahmen fast alle Eingriffe traditionell in Lokal- bzw. Regionalanästhesie und oft auch in räumlich-infrastruktureller Trennung von den großen Zentral-Operationssälen stattfinden können. Die peri- und postoperative Überwachung obliegt dabei dem dermatochirurgischen Operationsteam. Das sui generis kleinere OP-Team hat somit eine ganze Reihe perioperativer Notwendigkeiten zu beachten, um die sich in den "großen" chirurgischen Fächern eine Vielzahl verschiedener beteiligter Fachgruppen gemeinsam kümmern. Hierzu gehören neben Hygieneaspekten, Kenntnissen in der Überwachung der Patienten sowie dem Aspekt der surgical site infections auch Fragen zur postoperativen Schmerztherapie sowie detailliertes pharmakologisches Wissen über die zur Anwendung kommenden Lokalanästhetika und das Handling der damit assoziierten toxischen und allergischen Reaktionen. Eine interdisziplinäre Zusammenarbeit und Verantwortung für den Patienten ist notwendig und erfordert die Erarbeitung und Umsetzung qualitätsorientierter und evidenzbasierter Handlungsanweisungen, die im dermatochirurgischen OP-Setting meist weit über das eigentliche Fach hinausgehen. Ziel dieses Weiterbildungsartikels soll die komprimierte Darstellung der genannten fachübergreifenden Standpunkte bezüglich der wichtigsten perioperativen Aspekte sein.

Safety of metamizole: a systematic review of the literature

WHAT IS KNOWN AND OBJECTIVE

Metamizole was withdrawn from the market in the United States and several European countries following reports of fatal agranulocytosis among users, but is still available in many countries in Europe, South America and Asia. Over the past several decades, a number of epidemiologic studies have been conducted to quantify the risk of agranulocytosis and other adverse effects associated with metamizole and other non-narcotic analgesics. The objective of this study was to perform a systematic review of the safety of metamizole.

METHODS

Epidemiologic studies published between 1 January 1980 and 15 December 2014 were identified through systematic searches of PubMed and Google Scholar; the reference sections of selected articles were also reviewed to identify potentially relevant studies. Studies included in this review focused on the safety of metamizole, that is on outcomes such as haematologic abnormalities, gastrointestinal bleeding, anaphylaxis and hepatotoxicity. Two study investigators independently reviewed the abstracts and articles to determine relevant studies according to prespecified criteria.

RESULTS AND DISCUSSION

A total of 22 articles met the criteria for evaluation. The majority of studies that evaluated agranulocytosis indicated an increased risk associated with metamizole, with relative risk (RR) estimates ranging from 1·5 (95% CI, 0·8-2·7) to 40·2 (95% CI, 14·7-113·3). Findings of three case-control studies do not suggest an association between metamizole and aplastic anaemia. Of the five case-control studies that evaluated the risk of upper gastrointestinal bleeding, four found a statistically significant increased risk associated with metamizole (RR estimates ranging from 1·4 to 2·7). There is insufficient evidence to determine whether metamizole increases the risk of other outcomes (e.g. hepatic effects, anaphylaxis, congenital anomalies). Few studies evaluated the effects of dose, route of administration or duration of therapy.

WHAT IS NEW AND CONCLUSION

Published studies reported differences in the magnitude of risk of adverse outcomes associated with metamizole use and often had small sample sizes and a number of other limitations that may have biased the results. Further research is needed to better quantify the potential risks associated with metamizole compared to other non-narcotic analgesics.

[Pediatric perioperative systemic pain therapy: Austrian interdisciplinary recommendations on pediatric perioperative pain management]

BACKGROUND

Many analgesics used in adult medicine are not licensed for pediatric use. Licensing limitations do not, however, justify that children are deprived of a sufficient pain therapy particularly in perioperative pain therapy. The treatment is principally oriented to the strength of the pain. Due to the degree of pain caused, intramuscular and subcutaneous injections should be avoided generally.

NON-OPIOIDS

The basis of systemic pain therapy for children are non-opioids and primarily non-steroidal anti-inflammatory drugs (NSAIDs). They should be used prophylactically. The NSAIDs are clearly more effective than paracetamol for acute posttraumatic and postoperative pain and additionally allow economization of opioids. Severe side effects are rare in children but administration should be carefully considered especially in cases of hepatic and renal dysfunction or coagulation disorders. Paracetamol should only be taken in pregnancy and by children when there are appropriate indications because a possible causal connection with bronchial asthma exists. To ensure a safe dosing the age, body weight, duration of therapy, maximum daily dose and dosing intervals must be taken into account. Dipyrone is used in children for treatment of visceral pain and cholic. According to the current state of knowledge the rare but severe side effect of agranulocytosis does not justify a general rejection for short-term perioperative administration.

OPIOIDS

In cases of insufficient analgesia with non-opioid analgesics, the complementary use of opioids is also appropriate for children of all age groups. They are the medication of choice for episodes of medium to strong pain and are administered in a titrated form oriented to effectiveness. If severe pain is expected to last for more than 24 h, patient-controlled anesthesia should be implemented but requires a comprehensive surveillance by nursing personnel.

KETAMINE

Ketamine is used as an adjuvant in postoperative pain therapy and is recommended for use in pediatric sedation and analgosedation.

Who gets dipyrone (metamizole) in Germany? Prescribing by age, sex and region

WHAT IS KNOWN AND OBJECTIVE

Metamizole (dipyrone) is an analgesic that has been the focus of considerable controversy regarding its safety. Because of potentially life-threatening blood disorders such as agranulocytosis, it has been withdrawn in many countries but not in Germany, where prescribing even increased over recent years. We aimed to evaluate prescribing of metamizole in Germany with respect to age, sex and regional variations.

METHODS

Using data of a statutory health insurance, we analysed a cohort of 1·7 million persons who were insured at least 1 day in each quarter of 2009. Outcome of interest was the outpatient prescription prevalence, for example the proportion of persons receiving at least one prescription of metamizole.

RESULTS AND DISCUSSION

A total of 6·8% received metamizole with a higher prescribing prevalence in females (7·8% vs. 6·0%). The prevalence increased with age up to 26·7% in persons ≥85 years (men: 21·1%; and women: 30·4%). We found large regional variations with higher prevalences in the northern part of Germany. Most of the prescriptions were issued by general practitioners (78·9%). 58·3% were liquid oral formulations with considerable regional variations ranging between 32·3% in Mecklenburg-West Pomerania and 67·3% in North Rhine-Westphalia. Overall, liquid oral forms are much more often prescribed in the western than in the eastern part of Germany.

WHAT IS NEW AND CONCLUSION

Metamizole - a drug with a relatively narrow indication - is often prescribed in Germany with relevant differences by age, sex and region. Qualitative studies should clarify reasons for this. Further quantitative research should investigate small-area variations, indications and treatment durations.

Metamizole-induced agranulocytosis revisited: results from the prospective Berlin Case-Control Surveillance Study

PURPOSE

Treatment with metamizole (dipyrone) has steadily increased in Germany over the last decade. The consequences of this increase for metamizole-induced agranulocytosis (MIA) are unclear. The present study addressed this topic using data from the Berlin Case-Control Surveillance Study.

METHODS

Adult patients (≥18 years of age) with acute nonchemotherapy-induced agranulocytosis were identified by active surveillance in all 51 Berlin hospitals between 2000 and 2010. Cases related to metamizole were ascertained applying the drug causality criteria of the World Health Organization. The incidence rate of MIA was calculated and standardised by age and sex based on the German standard population in 2010.

RESULTS

Twenty-six MIA cases out of 88 (30 %) patients with validated agranulocytosis were ascertained. The incidence of MIA was 0.96 (95 % confidence interval (CI) 0.95-0.97) cases per million per year. The median age of MIA cases was 50 years (quartile (Q)1 31 years; Q3 68 years) and 19 (73 %) of them were women. In 17 (65 %) cases, neutrophil granulocytes dropped below the value of 0.1 × 10(9) cells/L with three patients suffering from sepsis. Headache and postoperative pain were the most frequent indications for metamizole in outpatients (n = 16) and inpatients (n = 10), respectively. The median treatment duration was 6 days (Q1 4 days; Q3 19 days).

CONCLUSIONS

MIA persists as a severe condition in current pharmacotherapy. The continuous increase of metamizole applications should be critically assessed, especially in regard to indications in the outpatient setting and with respect to metamizole treatment duration.

WITHDRAWN: Dipyrone for acute primary headaches

The original authors of this review are unable to update it. The Cochrane Pain, Palliative and Supportive Care Review Group (PaPaS) is seeking new authors to update and split the review into two separate reviews on migraine and tension‐type headache. If you are interested, please contact the Managing Editor of PaPaS (contact details provided under 'Contact Person').

At July 2014, this review has been withdrawn. This review is out of date although it is correct as of the date of publication. The latest version is available in the ‘Other versions’ tab on The Cochrane Library, and may still be useful to readers.

The editorial group responsible for this previously published document have withdrawn it from publication.

Treatment of postoperative pain after total hip arthroplasty: comparison between metamizol and paracetamol as adjunctive to opioid analgesics-prospective, double-blind, randomised study

INTRODUCTION

Metamizole use has been limited because of its risk of agranulocytosis. However, more recent literature seems to support its safety. This prospective, randomised, double-blind study was conducted to compare the analgesic effects of intravenous metamizole or intravenous paracetamol in combination with morphine PCA during the first 24 h following total hip arthroplasty.

MATERIALS AND METHODS

One hundred ten consecutive patients were selected for study. The two study groups were (A) metamizole, (B) paracetamol. Postoperative pain therapy was provided by Morphine PCA pump. In the first treatment group (A group), all patients received intravenous metamizole 1.5 g every 8 h during the first 24 postoperative hours. In the second treatment group (B group), all patients received intravenous paracetamol 1 g every 8 h during the first 24 postoperative hours. Postoperative pain intensity was measured 1, 2, 3, 4, 6, 8, 10, 14, 18, 22 h after the end of surgery by a VAS.

RESULTS

Statistically significant differences in VAS pain values favoring metamizole were reported at 6-h (p = 0.038), 8-h (p = 0.036), 14-h (p = 0.011), 18-h (p < 0.001) and 22-h (p = 0.025) post-baseline. Mean cumulative pain values were 17.9 for metamizole and 30.6 for paracetamol.

CONCLUSIONS

In this study, we have also shown excellent efficacy of paracetamol and metamizole combined with opioids, but metamizole proved to be a better analgesic than paracetamol. It is also necessary to mention the financial aspect considering that intravenous paracetamol is about ten times more expensive than an equivalent analgesic doses of intravenous metamizole.

Analgésicos, antipiréticos e anti-inflamatórios não esteroides em prescrições pediátricas

O uso de analgésicos, antipiréticos e anti-inflamatórios não esteroides por crianças muitas vezes não tem aprovação das agências reguladoras, nem respaldo das evidências científicas. Prescrições pediátricas podem ser influenciadas por fatores que não favorecem o uso racional dos medicamentos desta classe. O objetivo deste trabalho foi avaliar a utilização de analgésicos, antipiréticos e anti-inflamatórios não esteroides em crianças, considerando os setores público (SUS) e privado (N-SUS). A amostra foi composta por 150 prescrições (101 SUS e 49 N-SUS) seguidas de entrevista aos cuidadores, em dezoito locais (nove drogarias privadas e nove Unidades de Saúde do SUS). Os medicamentos foram prescritos de forma apropriada, segundo faixa etária, somente em 21,8% (SUS) e 29,6% (N-SUS) das prescrições. Mais de 95% das receitas, independente da origem, não atenderam aos critérios estabelecidos para avaliação do uso racional, com erros de dose, frequência e duração do tratamento. A análise das prescrições de analgésicos, antipiréticos e anti-inflamatórios não esteroides para crianças não apresentou diferenças significantes nos setores público e privado.

Off-label and unlicensed drug utilization in hospitalized children in Fortaleza, Brazil

OBJECTIVES

To investigate the use of drugs, the extent and pattern of unlicensed and off-label use, and the potential relationship between off-label drug use and adverse drug reactions in northeastern Brazil.

METHODS

A follow-up study of drug utilization in a general ward of a pediatric reference hospital, involving patients hospitalized for more than 24 h. Prescriptions and medical records were reviewed daily from August to December 2001. Drug licensing status of all prescriptions given to these patients was determined.

RESULTS

A total of 272 patients were admitted during the study, 265 (97.4%) of whom received one or more drugs. The median number of drugs/patient was 6 (1-18), and the most frequent diagnosis was pneumonia (29.4% of patients). The therapeutic class most prescribed was anti-infectives for systemic use (68.8% of all children). In all, 82.6% of children received at least one unlicensed or off-label drug, and 17% received both an unlicensed and an off-label drug. Dose/frequency was the most common form of off-label drug use. Off-label drug use was significantly associated with adverse drug reactions (relative risk 2.44; 95% CI 2.12, 2.89).

CONCLUSIONS

Although off-label drug use is a complex issue and is not synonymous with inappropriate drug use, a high rate of unlicensed/off-label drug use was found and was also associated with an increased risk of adverse drug reactions. More efforts are needed to increase rational drug use in children.

Adjunct dipyrone in association with oral morphine for cancer-related pain: the sooner the better

INTRODUCTION

Adjunct nonopioid analgesics may improve pain control in patients with cancer needing morphine or its derivates. Dipyrone is a cheap nonopioid analgesic widely used in many countries.

OBJECTIVE

The objective of the study was to evaluate, whenever morphine was started, if associating dipyrone with it would improve pain control and if this effect was time dependent.

MATERIALS AND METHODS

This is a double-blind placebo-controlled randomized crossover study. Thirty-four ambulatory cancer patients experiencing cancer-related pain for which oral morphine was to be started at the dose of 10 mg orally (PO) every 4 h were randomized to take either dipyrone 500 mg PO every 6 h or placebo. After 48 h, patients would be switched from dipyrone to placebo and vice versa. Pain was the primary outcome and was measured using a visual analogue scale before starting medications, at 48 and 96 h.

RESULTS

We randomized 16 patients to start with placebo (group 1) and 18 with dipyrone (group 2). Pain scores for groups 1 and 2 were at baseline: 7.31 +/- 0.29 vs 6.88 +/- 0.28 (p = 0.3), at 48 h: 7.06 +/- 0.32 vs 5.5 +/- 0.31 (p = 0.001), and at 96 h: 3.18 +/- 0.39 vs 1.94 +/- 0.37 (p = 0.03). Both groups had significant improvements in pain scores after introducing dipyrone (p < 0.001, for both). Main toxicities were nausea, vomiting, epigastric pain, and myalgias. Twenty-eight patients chose dipyrone, four placebo, and two were indifferent.

CONCLUSIONS

We conclude that dipyrone adds significantly to the analgesic effect of morphine and, when given at the time of starting morphine, results in better pain scores even after dipyrone is discontinued.

Effects of parecoxib and dipyrone on platelet aggregation in patients undergoing meniscectomy: a double-blind, randomized, parallel-group study

BACKGROUND

Based on a PubMed search of the literature using the terms parecoxib, platelets, thromboxane, bleeding, and platelet aggregation, the effects of parecoxib on platelet function have not fully been established under clinical conditions.

OBJECTIVE

The aim of this study was to determine platelet aggregation, thromboxane B(2) (TxB(2)) formation, and plasma concentrations with the use of parecoxib in postoperative pain management.

METHODS

This double-blind, randomized, parallel-group trial was conducted at the University Hospital for Orthopedic Surgery, Friedrichsheim, Frankfurt, Germany. Male and female patients aged 18 to 55 years and scheduled to undergo routine partial meniscectomy (or a similar arthroscopic procedure) were eligible. All patients received dose-adjusted enoxaparin before surgery and parecoxib 40 mg BID or dipyrone 1000 mg QID. Blood samples were drawn before first injection (predose) and at 0.5, 2, and 6 hours after injection. Platelet aggregation (expressed as percentage of the maximal light transmittance [A(max)]) was induced with arachidonic acid (A(max)AA) and collagen (A(max)CO). TxB(2) formation was determined using enzyme-linked immunosorbent assay.

RESULTS

This study included 26 patients. In both treatment groups, 8 males and 5 females, all white, were enrolled. In the dipyrone group, the mean age was 48 years (range, 32-61 years) and the mean weight was 85 kg (range, 63-122 kg); in the parecoxib group, the mean age was 47 years (range, 31-61 years) and the mean weight was 81 kg (range, 57-100 kg). Median (interquartile range [IQR]) predose values for A(max)AA were 76% (65%-83%) in the parecoxib group and 87% (80%-89%) in the dipyrone group. At 0.5 hour after injection, A(max)AA was 52% (5%-77%) with parecoxib and 8% (0%-11%) with dipyrone (P=0.004). At 2 hours after injection, A(max)AA was 78% (72%-80%) in the parecoxib group versus 7% (5%-11%) in the dipyrone group (P<0.001). At 6 hours after study drug administration, no treatment differences were found. For A(max)CO, no statistically significant differences were found. Consistent with the stronger inhibition of aggregation, patients who received dipyrone had lower TxB(2) formation values. Six hours after parecoxib administration, mean TxB(2) formation was significantly enhanced compared with predose values (132 ng/mL [IQR, 62-228 ng/mL] vs 185 ng/mL [IQR, 135-239 ng/mL]; P=0.05).

CONCLUSIONS

Platelet aggregation and TxB(2) formation were significantly lower for 6 hours in dipyronetreated patients compared with parecoxib-treated patients. In contrast, TxB(2) formation was increased with parecoxib 6 hours after administration compared with pretreatment values. In this small study, parecoxib did not affect platelet aggregation in a population of patients undergoing routine partial meniscectomy (or a similar arthroscopic procedure) under clinical conditions.

Dipyrone for acute primary headaches

BACKGROUND

Dipyrone is used to treat headaches in many countries, but is not available in others (particularly the USA and UK) because of its association with potentially life-threatening blood dyscrasias such as agranulocytosis.

OBJECTIVES

To determine the effectiveness and safety of dipyrone for acute primary headaches in adults and children.

SEARCH STRATEGY

We searched the Cochrane Pain, Palliative & Supportive Care Group's Trials Register; the Cochrane Central Register of Controlled Trials; MEDLINE; EMBASE; LILACS, and the reference lists of included studies.

SELECTION CRITERIA

Double-blind randomised controlled trials of dipyrone for the symptomatic relief of acute primary headaches in adults and children.

DATA COLLECTION AND ANALYSIS

Three authors independently screened articles, extracted data, assessed trial quality and analysed results. Relative risks (RRs), risk differences (RDs), weighted mean differences (WMDs), and numbers-needed-to-treat (NNTs) were calculated as appropriate.

MAIN RESULTS

Four trials involving a total of 636 adult subjects were included. Methodological quality was generally high. One study each evaluated oral and intravenous dipyrone for episodic tension-type headache (ETTH); two trials evaluated intravenous dipyrone for migraine, but only one of these described pain outcomes. No pediatric trials were identified. The largest trial (n = 356) evaluated two doses (0.5 g, 1 g) of oral dipyrone for ETTH, which were significantly better than placebo for pain relief. The 1 g dose was also significantly better than acetylsalicylic acid (ASA) 1 g . A smaller trial (n = 60) evaluated intravenous dipyrone 1 g versus placebo for ETTH. RRs were statistically significant favouring dipyrone for pain-free and headache improvement outcomes. Finally, one trial (n = 134) evaluated intravenous dipyrone 1 g versus placebo for pain outcomes in patients with migraine. RRs were again statistically significant favouring dipyrone for pain-free and headache improvement outcomes. Two of the four trials assessed adverse events. No serious adverse events were reported, and no significant differences in adverse events were detected between dipyrone and comparators (placebo and ASA).

AUTHORS' CONCLUSIONS

Evidence from a small number of trials suggests that dipyrone is effective for ETTH and migraine. No serious adverse events were observed in the included trials, but agranulocytosis is rare and would probably not be observed in such a relatively small sample. A study now ongoing in Latin America may clarify the true risk of agranulocytosis associated with dipyrone use.

A population-based case-control teratologic study of oral dipyrone treatment during pregnancy

OBJECTIVE

To study the possible human teratogenic effect of oral dipyrone, an antipyretic and analgesic drug treatment during pregnancy.

DESIGN AND SETTING

The analysis of cases with different congenital abnormalities and their matched population controls without congenital abnormalities, in addition to a comparison between cases and malformation controls (Down's syndrome) in the population-based, large data set of the Hungarian Case-Control Surveillance of Congenital Abnormalities, 1980-1996.

STUDY PARTICIPANTS

22 843 neonates or fetuses with congenital abnormalities (cases), 38 151 matched newborns without congenital abnormalities (population controls) and 834 neonates or fetuses with Down's syndrome (malformation controls).

MAIN OUTCOME MEASURES

25 congenital abnormality groups.

RESULTS

1382 (6%) cases, 1911 (5%) population controls and 74 (8.9%) malformation controls were born to mothers treated with dipyrone during pregnancy. The case-matched population control analysis showed a higher rate of diaphragmatic defect (adjusted prevalence odds ratio [POR] 2.7; 95% CI 1.0, 6.8), cardiovascular malformations (POR 1.3; 95% CI 1.0, 1.7) and other isolated congenital abnormalities (POR 1.8; 95% CI 1.1, 2.9) after oral dipyrone treatment during the second and third months of gestation, i.e. in the critical period for most major congenital abnormalities. However, the evaluation of only medically recorded dipyrone use did not confirm these possible associations. The comparison of dipyrone treatment between 25 congenital abnormalities groups and malformation controls as the referent group also did not show any difference in the dipyrone use during the second and third months of gestation.

CONCLUSIONS

The higher occurrence of dipyrone treatment in the case mothers compared with population control mothers can be explained by recall bias and/or chance. However, the higher rate of diaphragmatic congenital abnormalities can be considered as a signal and merits further investigation.

[Effectiveness of early dipyrone administration on severity of dengue virus infection in a prospective cohort]

OBJECTIVE

To evaluate the impact of dipyrone administration in the first days of the disease on the severity of dengue infection.

MATERIALS AND METHODS

Prospective cohort study in adults (> 12 years) with dengue virus infection, confirmed by specific IgM titers in paired samples or isolation of the virus. The patients were enrolled in the first 96 hours of the disease. Basic demographic details, symptoms, drugs received and examination findings were recorded at admittance. A detailed clinical examination and hematocrit determination were done every day by a member of the study team until day 7 of disease. Platelet count was performed at baseline and with the development of spontaneous bleeding or evidence of plasma leakage. The association between dipyrone use in the first 96 hours of disease and the risk of dengue hemorrhagic fever (DHF) was evaluated.

RESULTS

Seven of the 110 patients enrolled developed DHF. At admission, 17 patients had received dipyrone and administration of this drug was not related to the clinical manifestations of dengue, or the use of other medication. Dipyrone was associated with an increased risk of presenting DHF (RR = 7.29; 95% CI: 1.79-29.34; P = 0.0016). Minimum platelet count in the dipyrone group (median: 105,588.2 plat/microl), was significantly smaller than that of the control group (median: 145,698.9 plat/microl): difference = 40,110.69 plat/microl; 95% CI: 1597.36-78,624.02; P = 0.0414.

CONCLUSIONS

Our data suggest that early administration of dipyrone in patients with disease caused by dengue virus is associated with lower platelet counts and an increased risk of developing DHF.

Perioperative Schmerztherapie in der Kniegelenkendoprothetik

Total knee arthroplasty (TKA) is associated with significant postoperative pain. Adequate analgesics and techniques are required for early mobilization, continuous passive motion and intensified physical therapy as well as for high-quality postoperative analgesia.However, in the immediate postoperative setting the excessive nociceptive input can be blocked by using doses which are most frequently associated with adverse effects like dizziness, nausea and vomiting, sedation and risk of respiratory depression. The use of peripheral nerve blocks is recommended after orthopaedic surgery. After TKA, the continuous "3 in 1 nerve block" has been proven to be more effective than conventional patient controlled intravenous opioid therapy as well as than epidural analgesia accompanied by side effects. Postoperative analgesic techniques influence surgical outcome, duration of hospitalization and re-convalescence. The use of regional analgesia after TKA may initially lead to higher costs but it is counterbalanced by a reduction in morbidity and mortality, decrease in hospitalization, improved re-convalescence and a better functional outcome.

Metamizol (dipyrone, optalgin) in pregnancy, is it safe? A prospective comparative study

AIM

To assess the teratogenic effect of metamizol when used during the first trimester of pregnancy.

METHODS

One hundred and eight women who used metamizol during the first trimester of pregnancy were recruited from 4 teratogen information centers in Israel (3) and in Italy (1). The study group was paired for age, smoking habits and alcohol consumption with a comparative group exposed to acetaminophen.

RESULTS

Maternal demographics and history, birth weight, gestational age at delivery, rate of live births, spontaneous abortions and fetal distress were comparable in both groups. The rate of major malformations in the metamizol group (3%) did not differ significantly from the rate in the comparative group (2%) (P = 0.57, relative risk = 1.55, 95% confidence interval 0.26-9.05).

CONCLUSIONS

Our data may suggest that exposure to metamizol during the first trimester of pregnancy is probably not associated with a significantly increased risk for malformations or spontaneous abortions.

Agranulocytosis associated with dipyrone (metamizol)

OBJECTIVES

Reported estimates of the risk of agranulocytosis associated with metamizol have varied by several orders of magnitude. We assessed this association in a large database for the surveillance of blood dyscrasias.

METHODS

Since 1980, all laboratory units of haematology in a defined area (3.3-4.1x10(6) inhabitants) contribute to the ascertainment of all cases of agranulocytosis meeting strict diagnostic criteria. These cases of patients with agranulocytosis and sex-, age-, hospital- and date-matched controls were interviewed using a structured questionnaire about previous drug exposures, and relative risks were calculated for several categories of exposure to metamizol.

RESULTS

After a total follow-up of 78.73x10(6) person-years, 273 community cases of agranulocytosis had been found--of which 96 were excluded for various reasons and 177 were included in the case-control analysis--and were compared with 586 matched controls. Thirty cases of agranulocytosis (16.9%) and nine controls (1.5%) had been exposed to metamizol during the week before the index day. The adjusted relative risk was 25.8 [95% confidence interval (CI), 8.4-79.1], and the attributable incidence was 0.56 (0.4-0.8) cases per million inhabitants and per year. The risk disappeared after more than 10 days since the last dose of metamizol, and it increased with duration of use. Those with agranulocytosis exposed to metamizol had taken the drug for longer periods than the exposed controls. Compared with the cases recently reported from Sweden, the duration of use of metamizol by our exposed cases was substantially shorter, and the use of concomitant medications potentially causing agranulocytosis was lower.

DISCUSSION

In our milieu, agranulocytosis attributable to metamizol is rare. Geographical disparities in its risk estimate can be partly explained by differences in its patterns of use, in terms of dose, duration and concomitant medications.

[Postoperative pain therapy in orthopedics]

Postoperative pain management adheres to the principles of a three-step routine according to the WHO recommendations. This routine suggests the combination of a basic non-opioid (step I) with an opioid of low potency (step II) or high potency (step III). Non-opioids are routinely administered prior to an opioid. While i.v. application is the treatment of choice in the immediate postoperative course, a switch to oral pain medication is preferred as early as possible. With oral opioid therapy preference should be given to slow release drugs. Intramuscular application of pain medication has little place in postoperative pain management. In order to lower the need for systemic pain medication, postoperative pain management is supplemented by regional anesthesia administered pre- or intraoperatively. Requirement for pain medication beyond normal or increasing with postoperative time is suggestive of a postsurgical complication. Among the numerous drugs available for postoperative pain management, the physician is advised to confine his selection of pain medication to a limited number in order to gain superior knowledge of effects and side effects of the drugs administered.

Safety of Calcium Dobesilate in Chronic Venous Disease, Diabetic Retinopathy and Haemorrhoids

The aim of the present review is to consider the adverse effects and the safety profile of calcium dobesilate. Calcium dobesilate (Doxium) is a veno-tonic drug, which is widely prescribed in more than 60 countries from Europe, Latin America, Asia and the Middle East for three main indications: chronic venous disease, diabetic retinopathy and the symptoms of haemorrhoidal attack. Data sources used for this review comprise the international literature (1970-2003), a postmarketing surveillance (PMS) report for calcium dobesilate from OM Pharma (Geneva, Switzerland) covering the period 1974-1998, and periodic safety update reports (PSUR) covering the period 1995-2003 from the French Regulatory authorities pharmacovigilance database and OM Pharma. Data from the PMS report for 1974-1998 indicated that adverse events with calcium dobesilate did not occur very frequently and had the following distribution in terms of frequency: fever (26%), gastrointestinal disorders (12.5%), skin reactions (8.2%), arthralgia (4.3%), and agranulocytosis (4.3%). No deaths were attributed to calcium dobesilate in the PMS report. Using data on product use in the Swiss Compendium we estimated the prevalence of agranulocytosis to be 0.32 cases/million treated patients, i.e. ten times less than the calculated prevalence of agranulocytosis in the general population. Most adverse events are type B, i.e. rare and unrelated to the pharmacological properties of calcium dobesilate. This review concludes that the risk of an adverse effect with calcium dobesilate 500-1500 mg/day is low and constant over time. The recently raised problem of agranulocytosis (a total of 13 known cases drawn from all data sources) appears to be related to methodological bias. Such a review reinforces the need for a strong international pharmacovigilance organisation using similar methods to detect and analyse the adverse effects of drugs.