Metamizole-associated adverse events: a systematic review and meta-analysis

Use of dipyrone during pregnancy and risk of congenital anomalies: a systematic review

PURPOSE

This study aimed to summarize the evidence on the teratogenic effects of dipyrone used during pregnancy.

METHODS

Databases (MEDLINE, EMBASE, Cochrane Library, CINAHL, Web of Science, Lilacs, SciELO, SCOPUS, OasisBR, and OpenGray) were reviewed until September 2023. We included studies that compared pregnant women who used dipyrone during any gestational period with those who used other analgesics or did not use any analgesics during the same gestational period. The outcome assessed was the presence of any congenital anomaly. Two reviewers independently conducted the review process, and a third reviewer resolved any disagreements. The risk of bias was assessed using the Joanna Briggs Institute tool for observational studies. The reviewed data synthesis is presented in narrative form.

RESULTS

The search retrieved 2045 results, of which seven studies were included in the review, four were case‒control studies, and three were cohort studies involving 153,562 participants. The congenital anomalies evaluated varied across studies, with unspecified congenital anomalies predominating. Five of seven studies found no association between dipyrone and congenital anomalies. In a case‒control study, a positive association was found between dipyrone use and isolated congenital cataracts compared to two control groups; in another study, a positive association for unspecified congenital anomalies was observed in only one of the two control groups analyzed. In all studies, a high risk of bias was identified, especially regarding measuring the exposure, outcome, and assessment of confounding factors.

CONCLUSION

There is not enough evidence to define the risk of congenital anomalies associated with dipyrone use during pregnancy.

REGISTRATION

CRD 42022333041.

Adverse effects of metamizole on heart, lung, liver, kidney, and stomach in rats

BACKGROUND

Metamizole is banned in some countries because of its toxicity, although it is widely used in some European countries. In addition, there is limited information on its safety profile, and it is still debated whether it is toxic to the heart, lungs, liver, kidneys, and stomach.

AIMS

Our study investigated the effects of metamizole on the heart, lung, liver, kidney, and stomach tissues of rats.

METHODS

Eighteen rats were divided into three groups, wassix healthy (HG), 500 mg/kg metamizole (MT-500), and 1000 mg/kg metamizole (MT-1000). Metamizole was administered orally twice daily for 14 days. Meanwhile, the HG group received pure water orally. Biochemical, histopathologic, and macroscopic examinations were performed on blood samples and tissues.

RESULTS

Malondialdehyde (MDA), total glutathione (tGSH), superoxide dismutase (SOD), and catalase (CAT) in the lung and gastric tissues of MT-500 and MT-1000 groups were almost the same as those of the HG (p > 0.05). However, MDA levels in the heart and liver tissues of MT-500 and MT-1000 groups were higher (p < 0.05) compared to the HG, while tGSH levels and SOD, and CAT activities were lower (p < 0.05). MDA levels of MT-500 and MT-1000 groups in the kidney tissue increased the most (p < 0.001), and tGSH levels and SOD and CAT activities decreased the most (p < 0.001) compared to HG. Metamizole did not cause oxidative damage in the lung and gastric tissue. While metamizole did not change troponin levels, it significantly increased alanine aminotransferase (ALT), aspartate aminotransferase (AST), blood urea nitrogen (BUN), and creatinine levels compared to HG. Histopathologically, mild damage was detected in heart tissue, moderate damage in liver tissue, and severe damage in renal tissue. However, no histopathologic damage was found in any groups' lung and gastric tissues.

CONCLUSION

Metamizole should be used under strict control in patients with cardiac and liver diseases and it would be more appropriate not to use it in patients with renal disease.

Metamizole in the Management of Musculoskeletal Disorders: Current Concept Review

Metamizole, or dipyrone, has been used for decades as a non-narcotic analgesic, providing pain relief from musculoskeletal disorders and antipyretic and antispasmolytic properties. Despite being in use since the 1920s, its mechanism of action still needs to be discovered. Despite causing fewer adverse effects when compared to other analgesics, its harmful effects on the blood and lack of evidence regarding its teratogenicity make the usage of the drug questionable, which has led to it being removed from the drug market of various countries. This narrative review aims to provide a detailed insight into the mechanism of action and efficacy, comparing its effectiveness and safety with other classes of drugs and the safety profile of metamizole.

Pharmacologic Interventions to Immunologic and Immune-Mediated Conditions in Horses

Immunomodulators can stimulate, suppress, or regulate one or many aspects of the immune response. Use of a variety of immunostimulants, immunosuppressors, and anti-inflammatory drugs are described in horses, but the evidence supporting their efficacy is variable. Corticosteroids and nonsteroidal anti-inflammatory drugs are the best characterized immunomodulators in horses, but further study is needed to fully define their ideal dosing protocols and indications and to characterize the efficacy of other immunomodulators in equine medicine.

Discovering interactions in polypharmacy: Impact of metamizole on the metabolism of quetiapine

AIMS

Metamizole is quite an old drug with analgesic, antipyretic and spasmolytic properties. Recent findings have shown that it may induce several cytochrome P450 (CYP) enzymes, especially CYP3A4 and CYP2B6. The clinical relevance of these properties is uncertain. We aimed to unravel potential pharmacokinetic interactions between metamizole and the CYP3A4 substrate quetiapine.

METHODS

Plasma concentrations of quetiapine from a large therapeutic drug monitoring database were analysed. Two groups of 33 patients, either receiving quetiapine as a monotherapy (without CYP modulating comedications) or with concomitantly applied metamizole, were compared addressing a potential impact of metamizole on the metabolism of quetiapine being reflected in differences of plasma concentrations of quetiapine and dose-adjusted plasma concentrations.

RESULTS

Patients comedicated with metamizole showed >50% lower plasma concentrations of quetiapine (median 45.2 ng/mL, Q1 = 15.5; Q3 = 90.5 vs. 92.0 ng/mL, Q1 = 52.3; Q3 = 203.8, P = .003). The dose-adjusted plasma concentrations were 69% lower in the comedication group (P = .001). Subgroup analyses did not suggest a dose dependency of the metamizole effect or an influence of quetiapine formulation (immediate vs. extended release). Finally, the comedication group exhibited a significantly higher proportion of patients whose quetiapine concentrations were below the therapeutic reference range (78.8% in the metamizole group vs. 54.4% in the control group, P = .037) indicating therapeutically insufficient drug concentrations.

CONCLUSION

The combination of metamizole and quetiapine leads to significantly lower drug concentrations of quetiapine, probably via an induction of CYP3A4. Clinicians must consider the risk of adverse drug reactions, especially treatment failure under quetiapine when adding metamizole.

Safety of metamizole (dipyrone) for the treatment of mild to moderate pain-an overview of systematic reviews

Metamizole, as known as dipyrone or novaminsulfone is widely used, especially in Latin America, for its analgesic and antipyretic function. However, several countries have banned it due to the risk of agranulocytosis, skin necrosis, and other serious adverse effects. To assess the safety of metamizole compared to other commonly used non-opioid analgesics (paracetamol, ibuprofen, and acetylsalicylic acid). An overview of systematic reviews. The searches were performed in the PubMed, Cochrane Library, Embase, Scopus and LILACS databases. Systematic reviews of randomized and nonrandomized clinical trials with adult patients with mild to moderate pain that assessed the adverse effects of metamizole were included. A methodological quality assessment was performed through ROBIS. The protocol of this systematic review was submitted to the International Prospective Register of Systematic Reviews (Prospero, CRD42021295272). Of 387 identified studies, four were included, with a total of 20,643 participants, all submitted to a single dose by oral, intramuscular, or intravenous route. No study reported a serious adverse effect. However, 60 of 778 patients (7.7%) who used metamizole; 120/828 (14.5%) who used acetylsalicylic acid; 56/443 (12.6%) who used paracetamol; and 27/213 (12.7%) who used ibuprofen had mild adverse effects. A complementary statistical analysis showed that metamizole, at any dose, has a 38.8% lower chance of adverse effects compared to paracetamol and 46.8% compared to acetylsalicylic acid. The results shows that metamizole is a safe drug with evidence of a lower incidence of adverse effects compared to paracetamol and acetylsalicylic acid.

Management of analgesia in acute pancreatitis: Results of a national survey

INTRODUCTION

Acute pancreatitis is one of the main reasons for digestive admissions. Adequate pain treatment is crucial in its management. However, there are hardly any descriptions of the analgesic guidelines used in our setting.

METHODS

On-line survey on analgesic management in acute pancreatitis, aimed at attending physicians and residents practising in Spain.

RESULTS

Two hundred and nine physicians from 88 centres responded to the survey. Ninety percent were specialists in gastrointestinal medicine and 69% worked in a tertiary centre. The majority (64.4%) do not routinely use scales to measure pain. When choosing a drug, experience in its use was the most important factor. The most commonly prescribed initial treatments are: combination of paracetamol and metamizole (53.5%), paracetamol alone (19.1%) and metamizole alone (17.4%). As rescue: meperidine (54.8%), tramadol (17.8%), morphine chloride (17.8%) and metamizole (11.5%). Continuous perfusion is used in 8.2% of initial treatments. Physicians with >10 years of service use more metamizole as monotherapy (50%), while residents and attending physicians with <10 years of service prescribe it in combination with paracetamol (85%). If progression is needed, morphine chloride and meperidine are mainly used. The speciality of the respondent, the size of the work centre and the unit/service where the patients were admitted did not influence the analgesia prescribed. Satisfaction with pain management reached 7.8/10 (SD 0.98).

CONCLUSION

In our setting, metamizole and paracetamol are the most commonly used analgesics as initial pain treatment in acute pancreatitis, and meperidine is the most commonly used rescue analgesic.

The Adequacy of Anesthesia Guidance for Vitreoretinal Surgeries with Preemptive Paracetamol/Metamizole

Despite the possibility of postoperative pain occurrence, in some patients, vitreoretinal surgeries (VRSs) require performance of general anesthesia (GA). The administration of intraoperative intravenous rescue opioid analgesics (IROA) during GA constitutes a risk of perioperative adverse events. The Adequacy of Anesthesia (AoA) concept consists of an entropy electroencephalogram to guide the depth of GA and surgical pleth index (SPI) to optimize the titration of IROA. Preemptive analgesia (PA) using cyclooxygenase-3 (COX-3) inhibitors is added to GA to minimize the demand for IROA and reduce postoperative pain. The current analysis evaluated the advantage of PA using COX-3 inhibitors added to GA with AoA-guided administration of IROA on the rate of postoperative pain and hemodynamic stability in patients undergoing VRS. A total of 165 patients undergoing VRS were randomly allocated to receive either GA with AoA-guided IROA administration with intravenous paracetamol/metamizole or with preemptive paracetamol or metamizole. Preemptive paracetamol resulted in a reduction in the IROA requirement; both preemptive metamizole/paracetamol resulted in a reduced rate of postoperative pain as compared to metamizole alone. We recommend using intraoperative AOA-guided IROA administration during VRS to ensure hemodynamic stability alongside PA using both paracetamol/metamizole to reduce postoperative pain.

Analysis of Pain Management after Anatomic VATS Resection in Austrian Thoracic Surgery Units

BACKGROUND

Postoperative pain influences rehabilitation, postoperative complications and quality of life. Despite its impact, there are no uniform treatment guidelines. Different centers seem to use various strategies. This study aims to analyze pain management regimens used after anatomic VATS resections in Austrian thoracic surgery units, with a special interest in opioid usage and strategies to avoid opioids.

METHODS

A questionnaire was designed to assess the use of regional anesthesia, postoperative pain medication and characteristics of individual pain management regimens. The questionnaire was sent to all thoracic surgery units in Austria, with nine out of twelve departments returning them.

RESULTS

All departments use regional anesthesia during the procedure. Four out of nine centers use epidural analgesia or an intercostal catheter for postoperative regional anesthesia in at least 50% of patients. Two departments follow an opioid restrictive regimen, five depend on the visual analogue scale (VAS) and two administer opioids on a fixed schedule. Three out of nine departments use NSAIDs on a fixed schedule. The most used medication is metamizole (eight out of nine centers; six on a fixed schedule, two depending on VAS) followed by piritramide (six out of nine centers; none as a fixed prescription).

CONCLUSIONS

This study reflects the heterogeneity in postoperative pain treatment after VATS anatomic lung resections. All departments use some form of regional anesthesia in the perioperative period; prolonged regional anesthesia is not utilized uniformly to reduce opioid consumption, as suggested in enhanced recovery after surgery programs. More evidence is needed to optimize and standardize postoperative pain treatment.

Pharmacotherapeutic monitoring of dipyrone in northeastern Brazilian donkeys (Equus asinus)

This study aimed to monitor the effects of dipyrone following multiple administrations in northeastern donkeys. Ten castrated male donkeys, aged 6.4 ± 3 years and weighing 130.6 ± 9.8 kg, were administered dipyrone (25 mg/kg IV) every 12 h, resulting in six administrations (D1 to D6) per animal. Blood samples were collected over a 72 h monitoring period. A validated UHPLC-MS/MS method was employed to determine the plasma concentrations of the 4- methylaminoantipyrine (4-MAA) and 4-aminoantipyrine (4-AA). The calculated pharmacokinetic variables of 4-MAA after D1 and D6 were, respectively: Cmax (μg/mL) = 163.60 ± 179.72 and 178.79 ± 196.94; T1/2beta (h) = 2.65 ± 0.65 and 3.37 ± 1.03; and AUC0-t (μg/mL × h) = 240.38 ± 130.87 and 373.52 ± 78.85. The same variables for 4-AA were: Cmax, (μg/mL) = 0.44 ± 0.27 and 0.90 ± 0.31, T1/2beta (h) = 14.77 ± 13.13 and 35.97 and AUC0-t (μg/mL × h) = 3.20 ± 0.43 and 27.73 ± 11.99. Concentrations of 4-MAA exceeded the minimum concentration required for 50% inhibition of cyclooxygenases 1 and 2. However, an accumulation of 4-AA, was observed. Further clinical studies are necessary to ascertain the implications of these findings on the pharmacodynamic response to dipyrone in northeastern donkeys.

Dental Pain Medication Prescriptions in Minas Gerais, Brazil (2011-2021): A Time-Series Analysis

To describe trends of dentist-prescribed non-steroidal anti-inflammatory drugs (NSAIDs) and analgesics, from January 2011 to December 2021, as well as to examine the relationship between these trends and characteristics of public oral health services in Minas Gerais, Brazil. In this time-series analysis, all drugs were classified according to the Anatomical Therapeutic Chemical classification system. Drugs categorized as NSAIDs (M01A), and other analgesics and antipyretics (N02B) were included for analysis. The outcome was the number of Defined Daily Doses (DDDs)/1000 inhabitants/year for NSAIDs and analgesics in each town. Covariates referred to characteristics of public oral health services, such as coverage, estimates of dental procedures, and frequency of toothache. Linear time-series regression models were used to determine the influence of covariates on the outcome. Overall, there were 58,482 prescriptions of NSAIDs recorded in thirty-eight towns, while 47,499 prescriptions of analgesics in forty-three towns. For each year, there was a 0.38 (p < 0.001), and 0.28 (p < 0.001) increase in the average log of DDD/1000 inhabitants/year for NSAIDs and analgesics, respectively. A positive association was detected between toothache (p < 0.001) and the prescription of NSAIDs. Over the eleven years, there was a general rising trend in the prescriptions. Toothache was the only characteristic of public oral health services associated with the prescription rates of NSAIDs, implying that as the frequency of toothaches increase, so do the prescriptions of NSAIDs in the studied towns.

Opioid versus non-opioid postoperative pain management in otolaryngology

BACKGROUND

The opioid epidemic in the United States has had devastating consequences, with many opioid-related deaths and a significant economic toll. Opioids have a significant role in postoperative pain management. Here we aim to analyze differences in postoperative opioid and non-opioid pain medications regimens following common otolaryngological surgeries between two large tertiary care medical centers: the Milton S. Hershey Medical Center, USA (HMC) and The Chaim Sheba Medical center, Israel (SMC).

METHODS

A retrospective chart review of patients undergoing common otolaryngological procedures during the years 2017-2019 was conducted at two tertiary care centers, one in the U.S. and the other in Israel. Types and doses of postoperative pain medications ordered and administered during admission were analyzed. Average doses ordered and administered in 24 h were calculated. Opioid medications were converted to a standardized unit of morphine milliequivalents (MME). Chi-square test and Wilcoxon rank-sum test were used to compare the groups.

RESULTS

The study included 204 patients (103 U.S., 101 Israel). Patient demographics were similar except for a longer length of stay in Israel (p < 0.01). In the U.S., 95% of patients were ordered opioids compared to 70% in Israel (P < 0.01). In the U.S., 68.9% of patients ordered opioids received the medications compared to 29.7% in Israel. The median opioid dose ordered in the U.S. was 45MME/24 h compared to 30MME/24 h in Israel (P < 0.01), while median dose received in the U.S. was 15MME/24 h compared to 3.8MME/24 h in Israel (P < 0.01). Opioid prescriptions at discharge were given to 92% of patients in the U.S. compared to 4% of patients in Israel (p < 0.01). A significantly higher number of patients in the U.S. were prescribed acetaminophen and ibuprofen (p < 0.0001). Dipyrone was prescribed to 78% of patients in Israel.

CONCLUSIONS

HMC demonstrated a significantly more permissive approach to both prescribing and consuming opioid medications for postoperative pain management than SMC for similar, common otolaryngological surgeries. Non-opioid alternatives and examining the cultural and medical practice-based differences contributing to the opioid epidemic should be discussed and reevaluated.

The Pain Management of Trauma Patients in the Emergency Department

The vast majority of injured patients suffer from pain. Systematic assessment of pain on admission to the emergency department (ED) is a cornerstone of translating the best treatment strategies for patient care into practice. Pain must be measured with severity scales that are validated in clinical practice, including for specific populations (such as children and older adults). Although primary care ED of trauma patients focuses on resuscitation, diagnosis and treatment, pain assessment and management remains a critical element as professionals are not prepared to provide effective and early therapy. To date, most EDs have pain assessment and management protocols that take into account the patient's hemodynamic status and clinical condition and give preference to non-pharmacological approaches where possible. When selecting medications, the focus is on those that are least disruptive to hemodynamic status. Pain relief may still be necessary in hemodynamically unstable patients, but caution should be exercised, especially when using opioids, as absorption may be impaired or shock may be exacerbated. The analgesic dose of ketamine is certainly an attractive option. Fentanyl is clearly superior to other opioids in initial resuscitation and treatment as it has minimal effects on hemodynamic status and does not cause central nervous system depression. Inhaled analgesia techniques and ultrasound-guided nerve blocks are also increasingly effective solutions. A multimodal pain approach, which involves the use of two or more drugs with different mechanisms of action, plays an important role in the relief of trauma pain. All EDs must have policies and promote the adoption of procedures that use multimodal strategies for effective pain management in all injured patients.

Real-world evidence for beneficial effects of dipyrone in 4,278 patients with pulmonary hypertension - Analysis of the risk of ventilation, hospitalization, and agranulocytosis

INTRODUCTION

Dipyrone has been used as an analgesic for a century, but recently was proposed as a novel therapeutic strategy for the prevention and therapy of pulmonary hypertension (PH). The aim of this study was to analyze whether the risk for ventilation procedures and hospitalization was lower among patients with PH who used dipyrone compared to subjects who did not use dipyrone.

MATERIALS AND METHODS

Initially, patients with PH were retrieved from the TriNetX database, whereby subjects who used dipyrone were assigned to cohort I, and cohort II was formed by those individuals who did not use dipyrone. Both cohorts were matched for several variables. The outcomes were requirement for ventilation procedures and hospital admission, whereby the time window to record events was 5 years after diagnosis of PH. Subsequently, risk analysis was carried out, and risk ratio (RR) and odds ratio (OR) were calculated. In addition, the risk of agranulocytosis was determined for both cohorts.

RESULTS

Out of 741,875 individuals diagnosed with PH 4,282 and 737,593 patients were assigned to the cohorts I and II. After matching, each cohort accounted for 4,278 individuals. Among the cohorts I and II 10 and 187 individuals required ventilation procedures. The according risks of 0.2% vs. 4.4% were significantly different (p < 0.0001; Log-Rank test). RR and OR were 0.053 and 0.051. Within the cohorts I and II 10 and 1,195 subjects required hospital admission. The risks of hospitalization of 0,4% vs. 27.9% differed significantly (p < 0.0001). RR and OR were 0.016 and 0.012. Among the cohorts I and II 47 and 66 individuals were diagnosed with agranulocytosis, whereby no significance was found (p > 0.05).

CONCLUSIONS

The risk for ventilation measures and hospitalization among patients with PH was found to be significantly lower when dipyrone was used. Even though the underlying mechanisms remain unknown to date, they are supposedly mediated by an active metabolite of dipyrone. The obtained results appear to be promising for patients suffering from PH. Hence, the present study may encourage further research.

Symptom management in people dying with COVID-19: multinational observational study

OBJECTIVES

To describe multinational prescribing practices by palliative care services for symptom management in patients dying with COVID-19 and the perceived effectiveness of medicines.

METHODS

We surveyed specialist palliative care services, contacted via relevant organisations between April and July 2020. Descriptive statistics for categorical variables were expressed as counts and percentages. Content analysis explored free text responses about symptom management in COVID-19. Medicines were classified using British National Formulary categories. Perceptions on effectiveness of medicines were grouped into five categories; effective, some, limited or unclear effectiveness, no effect.

RESULTS

458 services responded; 277 UK, 85 rest of Europe, 95 rest of the world, 1 missing country. 358 services had managed patients with confirmed or suspected COVID-19. 289 services had protocols for symptom management in COVID-19. Services tended to prescribe medicines for symptom control comparable to medicines used in people without COVID-19; mainly opioids and benzodiazepines for breathlessness, benzodiazepines and antipsychotics for agitation, opioids and cough linctus for cough, paracetamol and non-steroidal anti-inflammatory drugs for fever, and opioids and paracetamol for pain. Medicines were considered to be mostly effective but varied by patient's condition, route of administration and dose.

CONCLUSIONS

Services were largely consistent in prescribing for symptom management in people dying with COVID-19. Medicines used prior to COVID-19 were mostly considered effective in controlling common symptoms.

[The challenges of managing thoracic pain in cystic fibrosis (CF)]

BACKGROUND

Cystic fibrosis (CF) is a rare genetic multisystemic disorder with progressive abdominal and pulmonary involvement. Pain is still an underestimated symptom in CF patients.

METHODS

A comprehensive review of guidelines and scientific literature on the topic was performed and combined with findings from pain management in a young CF patient with progressive thoracic pain.

RESULTS

German CF guidelines do not cover diagnosis and management of pain in these patients. Studies from Europe and the United States report interactions between intensity of pain and mortality in CF, but do not include data on the efficacy of pain management. These data and clinical observations of a CF patient with episodes of intense thoracic pain are used to illustrate the specific challenges in pain relief.

CONCLUSION

Pain management in CF requires meticulous monitoring as well as an interdisciplinary approach and should be implemented in the German CF guidelines. The authors also want to suggest recommendations for the treatment of thoracic pain in CF. The range and severity of organ involvement complicates the use both of opioids and non-opioids. Especially opioid treatment carries the risk of hypoxia and opioid-induced constipation (OIC) and needs close medical supervision.

Supramuscular upper blepharoplasty approach to orbital roof and/or lower anterior table frontal sinus fractures: A meta-narrative review

BACKGROUND

An approach to orbital roof fractures (ORFs) and/or lower anterior table frontal sinus fractures (LATFSFs) is a challenging task. The conventional coronal approach (CCA) appears to suit multiple/complex fractures of the upper face, while periorbital transcutaneous incisions (PTIs), e.g. gull wing, open sky, butterfly, and Lynch incisions, often impair aesthetic outcomes. The aims of this paper were to provide an overview of the supramuscular upper blepharoplasty approach (SUBA) to ORFs/LATFSFs.

METHODS

Using a meta-narrative review study design, the investigators enrolled published data extracted from PubMed/Medline, Embase, Cochrane Library, and Google Scholar concerning SUBA to ORFs/LATFSFs. Only publications with the highest and most recent level of evidence (LoE) in English, French or German available until 6 May 2022 were included. The LoE were evaluated using the 2011 Oxford Centre for Evidence-Based Medicine (OCEBM)'s classification.

RESULTS

In total, 70 articles were included; however, most contained low LoE. Under general and local anaesthesia, SUBA to ORFs/LATFSFs can be performed safely and appeared to be superior to its submuscular counterpart in terms of fewer risks of adjacent tissue injuries, and speedy operative time (maximal 5 min. in experienced hands).

CONCLUSIONS

In contrast to CCA and PTIs, the SUBA is a minimally invasive approach to the ORF/LATFSF with favourable aesthetic outcomes, direct visualisation of the fracture, quick operative time, rare complications, and easy learning.

Metamizole-Associated Risks in Decompensated Hepatic Cirrhosis

BACKGROUND

Because of the increased risk of acute renal failure (ARF), the use of cyclooxygenase (COX) inhibitors is not recommended in patients with decompensated hepatic cirrhosis. Metamizole is not a classic COX inhibitor, but there are insufficient data to support its safe use. In this study, we investigate the effect of metamizole on the risk of ARF in these patients.

METHODS

Metamizole use, ARF incidence, and patient mortality were examined in a large, retrospective, exploratory cohort and validated with data from a prospective registry.

RESULTS

523 patients were evaluated in the exploratory cohort. Metamizole use at baseline was documented in 110 cases (21%) and was independently associated with the development of ARF, severe (grade 3) ARF, and lower survival without liver transplantation at follow-up on day 28 (HR: 2.2, p < 0.001; HR: 2.8, p < 0.001; and HR: 2.6, p < 0.001, respectively). Interestingly, the risk of ARF depended on the dose of metamizole administered (HR: 1.038, p < 0.001). Compared to patients who were treated with opioids, the rate of ARF was higher in the metamizole group (49% vs. 79%, p = 0.014). An increased risk of ARF with metamizole use was also demonstrated in the independent validation cohort (p < 0.001).

CONCLUSION

Metamizole therapy, especially at high doses, should only be used with a high level of caution in patients with decompensated cirrhosis.

Liver Transplantation and the Use of Metamizole to Treat Drug-induced Liver Injury

Metamizole, or dipyrone, is a frequently prescribed analgetic drug that can cause drug-induced liver injury (DILI). Still, there are only a few metamizole-associated DILI cases (n = 61, including our study) described in the literature. So far liver transplantation has been reported in 6 patients with metamizole-induced acute liver failure. In 2020, a German group described a bigger cohort (n = 23) of metamizole-related DILI. Shortly thereafter, this issue gained wider attention as the German Federal Institute for Drugs and Medical Devices published a Direct Healthcare Professional Communication, emphasizing DILI as a potential adverse event caused by metamizole. We herein report 2 patients that were admitted to our liver transplant center due to acute liver failure (ALF) in April and May 2021. Both patients reported intake of metamizole as pain medication over a few weeks. After ruling out alternative reasons for ALF and fulfilling the King's College criteria both patients received emergency liver transplantations in our center. Pathology assessment of both explants were consistent with metamizole-associated DILI. As illustrated by our 2 cases of metamizole-induced liver failure with subsequent liver transplantation, this rare but presumably often overlooked adverse drug effect of metamizole should be considered as differential diagnosis in cases of cryptogenic liver failure.

Real world evidence of the use of metamizole (dipyrone) by the Brazilian population. A retrospective cohort with over 380,000 patients

Objective

To determine under which health conditions metamizole (dipyrone) is used as a single drug or as fixed-dose combination.

Methods

Two retrospective cohorts of Brazilian patients treated with metamizole between January 2015 and December 2017 were analyzed: a metamizole-based cohort (Cohort 1) and a symptoms-based cohort (Cohort 2). Anonymized patient data was obtained from Amil Clinical Data Warehouse. The number of patients with symptoms was described by age and sex.

Results

The sample size of the two cohorts consisted of 384,668 patients. In patients using metamizole (Cohort 1), the most common reason for medication was the treatment of some form of pain (81%), followed by fever (19%). Headache was the most common (19%) specified pain class, followed by sore throat (8%), muscular pain (6%), and abdominal pain (5%). In adult patients (n=276,279; 71.8%), metamizole was used as a monotherapy or associated with another drug, for any sort of pain, in over 88% of the patients. General pain was the main reason for metamizole use in children (61%).

Conclusion

Real world evidence to evaluate Brazilian patients’ therapeutic options is unusual and yet to be more explored using digital tools enabling better data registration. The present study confirmed that metamizole is widely used as a non-anti-inflammatory drug, and also showed the management of pain and fever as the most frequent indications in all age groups studied.

Registry in Clinical Trials Database: REBEC Database: 10507

Analgesic benefit of metamizole and ibuprofen vs. either medication alone: a randomized clinical trial

BACKGROUND

Postoperative pain relief remains a key problem after surgery. Multimodal pain therapy has proven beneficial in alleviating pain to a certain extent. However, when combining non-opioids, the focus has been on NSAIDs and paracetamol, but effects of combined use are only moderate. Metamizole could be a potent adjunct, due to its preclusion in several countries, data on its combined use are sparse, despite its common use in many countries. The aim of this study was to examine whether the combination of metamizole and ibuprofen is superior in relieving postoperative pain to either drug alone.

METHODS

For this randomized, placebo-controlled, cross-over study, 35 patients undergoing bilateral lower third molar extraction were randomized. Each patient received three applications of 1000mg metamizole + 400mg ibuprofen for surgery on one side and either 1000mg metamizole + placebo or 400mg ibuprofen + placebo on the other side. Pain ratings, rescue-medication (tramadol), and sleep were assessed for 18 hours.

RESULTS

The combined treatment of metamizole and ibuprofen showed lower mean pain scores over 12 hours than ibuprofen (2.4±1.3 vs 3.8±1.6; P=0.005)). Further, combined treatment showed lower mean pain scores over 6 hours than ibuprofen (2.0±1.2 vs. 3.1±1.6; P=0.022) or metamizole alone (2.0±1.2 vs. 3.3±1.7; P=0.015). Consumption of rescue medication was lowest in the combination-group (25% vs. 46%-metamizole; 50%-ibuprofen). The trial was stopped prematurely as the COVID-pandemic halted elective surgeries.

CONCLUSIONS

Combined use enables superior pain control compared to ibuprofen after molar extraction and tends to be superior to metamizole alone. The premature study-termination may overestimate this effect.

The antipyretic effectiveness of dipyrone in the intensive care unit: A retrospective cohort study

Introduction

Dipyrone (metamizol) is regularly used in critical care for pain and fever treatment, especially in Germany and Spain. However, indication for antipyretic therapy in critically ill patients is currently unclear and data for both the risk and benefit of dipyrone treatment in the intensive care environment are scarce. We hypothesized that antipyretic efficiency of dipyrone would not exceed antipyretic efficiency of acetaminophen. We therefore aimed to compare temperature courses in critically ill patients receiving either intravenous dipyrone, acetaminophen or no antipyretic medication.

Material and methods

We included 937 intensive care unit (ICU) patients with body temperature recordings of at least 37.5°C. We investigated temperature decrease associated with dipyrone or acetaminophen and additionally compared it to an untreated control group.

Results

Within the eight-hour study interval, maximum body temperature decrease in patients without antipyretic medication was -0.6°C (IQR: -1.0 to -0.4°C; n = 315). Maximal decrease in body temperature was higher both with dipyrone (-0.8°C (IQR: -1.2 to -0.4°C); p = 0.016; n = 341) and acetaminophen (-0.9°C (IQR: -1.6 to -0.6°C); p<0.001; n = 71), but did not differ between dipyrone and acetaminophen (p = 0.066). As compared to untreated patients, dipyrone only led to a marginal additional decrease in body temperature of only -0.1°C. Maximum of antipyretic effectiveness was reached four hours after administration.

Conclusion

Antipyretic effectiveness of dipyrone in ICU patients may be overestimated. Given the lack of prospective data, clinical evidence for antipyretic dipyrone therapy in the ICU is insufficient and warrants further critical evaluation.

Comparison between metamizole and triptans for migraine treatment: a systematic review and network meta-analysis

Objective The aim of this systematic review was to evaluate the efficacy of metamizole and triptans for the treatment of migraine. MethodsRandomized controlled trials including people who received metamizole or triptan by multiple routes of administration and at all doses as treatment compared to subjects who received another treatment or placebo were included in the systematic review. The primary outcomes were freedom from pain at 2 hours; pain relief at 2 hours; sustained headache response at 24 hours; sustained freedom from pain at 24 hours. The statistical analysis of all interventions of interest were based on random effect models compared through a network meta-analysis. Results 209 studies meeting the inclusion and exclusion criteria were analyzed. Of these, 130 had data that could be analyzed statistically. Only 3.0% provided enough information and were judged to have a low overall risk of bias for all categories evaluated; approximately 50% of the studies presented a low risk of selection bias. More than 75% of the studies presented a low risk of performance bias, and around 75% showed a low risk of detection and attrition bias. ConclusionThere is no evidence of a difference between dipyrone and any triptan for pain freedom after 2 hours of medication. Our study suggests that metamizole may be equally effective as triptans in acute migraine treatment.

Nonopioid analgesics for analgesia in critically ill patients: Friends, enemies, or collaborators

Patients in intensive care units (ICUs) experience pain, which they describe as a significant cause of stress during treatment. It can progress to chronic pain and significantly affect the quality of life. Opioids have long been the backbone of ICU pain therapy. The consequences of their long-term use are known today, such as prolonged ICU stay and mechanical ventilation, resulting in increased treatment costs. Additionally, abstinence syndrome is a consequence of abrupt opioid withdrawal. Also, there is a risk of tolerance and hyperalgesia after prolonged opioid use. Globally, opioid dependence after hospital opioid treatment is alarming, although there is still a lack of data on its incidence after ICU. Multimodal analgesia enables comfort to the patient, opioid-sparing, and avoidance of side effects of non-opioid analgesics. Nonsteroidal anti-inflammatory drugs (NSAIDs) are a broad group of drugs recommended with paracetamol to treat mild to moderate acute postoperative pain. Although often prescribed by intensivists, their use in treating painful conditions in ICU is controversial due to the possible consequences on the organs of critically ill patients. Due to the inhibition of cyclooxygenases, NSAIDs indirectly cause vasoconstriction of the renal arteries and arterioles, leading to kidney damage. NSAIDs inhibit platelet aggregation and may predispose to bleeding. Analgesia of a critically ill patient is a important part of their treatment, however it can be challenging in certain patients. Numerous combinations of pharmacological and non-pharmacological approaches can be adapted to the patient's current characteristics.

Metamizole Use in Children: Analysis of Drug Utilisation and Adverse Drug Reactions at a German University Hospital between 2015 and 2020

BACKGROUND

Metamizole use is controversially discussed due to its potentially serious adverse drug reactions (ADRs). In Germany, however, it remains a popular analgesic and antipyretic drug.

OBJECTIVE

The aim of this study was to discuss the safety profile of metamizole in children by analysing the inpatient prescription patterns and presenting the metamizole-related ADRs at a paediatric hospital between 2015 and 2020.

METHODS

Metamizole utilisation data were retrospectively analysed from electronic medical records. ADRs were prospectively recorded via the hospital's stimulated reporting system and analysed accordingly. Patients aged < 18 years admitted to one of the general wards of the department of paediatrics and adolescent medicine of a German university hospital between June 2015 and May 2020 who received at least one drug therapy within their inpatient stay were included in the analysis. Causality of ADRs was rated according to the World Health Organisation causality assessment.

RESULTS

In 31.7% (3759/11,857) of the inpatient stays of 7809 patients, metamizole was administered. Metamizole exposure was highest in adolescents (37.9%) and lowest in newborns (9.9%). Overall, metamizole was administered parenterally in about 90%. Three cases of agranulocytosis, one allergic shock and one rash with possible or higher causality to metamizole treatment were reported. Three of these occurred prior to hospitalisation. All patients recovered without remaining harm.

DISCUSSION

Metamizole is commonly used in paediatric inpatients in Germany. Serious ADRs occur but rarely. Continuous monitoring of drug therapy through, for example, stimulated reporting systems ensures that serious ADRs are detected, and appropriate interventions can be introduced.

Excess Mortality in Aspirin and Dipyrone (Metamizole) Co-Medicated in Patients With Cardiovascular Disease: A Nationwide Study

Background

Pain is a major issue in our aging society. Dipyrone (metamizole) is one of the most frequently used analgesics. Additionally, it has been shown to impair pharmacodynamic response to aspirin as measured by platelet function tests. However, it is not known how this laboratory effect translates to clinical outcome.

Methods and Results

We conducted a nationwide analysis of a health insurance database in Germany comprising 9.2 million patients. All patients with a cardiovascular event in 2014 and subsequent secondary prevention with aspirin were followed up for 36 months. Inverse probability of treatment weighting analysis was conducted to investigate the rate of mortality, myocardial infarction, and stroke/transient ischemic attack between patients on aspirin‐dipyrone co‐medication compared with aspirin‐alone medication. Permanent aspirin‐alone medication was given to 26,200 patients, and 5946 patients received aspirin–dipyrone co‐medication. In the inverse probability of treatment weighted sample, excess mortality in aspirin–dipyrone co‐medicated patients was observed (15.6% in aspirin‐only group versus 24.4% in the co‐medicated group, hazard ratio [HR], 1.66 [95% CI, 1.56–1.76], P<0.0001). Myocardial infarction and stroke/transient ischemic attack were increased as well (myocardial infarction: 1370 [5.2%] versus 355 [5.9%] in aspirin‐only and co‐medicated groups, respectively; HR, 1.18 [95% CI, 1.05–1.32]; P=0.0066, relative risk [RR], 1.14; number needed to harm, 140. Stroke/transient ischemic attack, 1901 [7.3%] versus 506 [8.5%] in aspirin‐only and co‐medicated groups, respectively; HR, 1.22 [95% CI, 1.11–1.35]; P<0.0001, RR, 1.17, number needed to harm, 82).

Conclusions

In this observational, nationwide analysis, aspirin and dipyrone co‐medication was associated with excess mortality. This was in part driven by ischemic events (myocardial infarction and stroke), which occurred more frequently in co‐medicated patients as well. Hence, dipyrone should be used with caution in aspirin‐treated patients for secondary prevention.

Grade 4 Neutropenia Secondary to Immune Checkpoint Inhibition - A Descriptive Observational Retrospective Multicenter Analysis

Introduction

Immune checkpoint inhibitors (ICI) are increasingly being used to treat numerous cancer types. Together with improved recognition of toxicities, this has led to more frequent identification of rare immune-related adverse events (irAE), for which specific treatment strategies are needed. Neutropenia is a rare hematological irAE that has a potential for a high mortality rate because of its associated risk of sepsis. Prompt recognition and timely treatment of this life-threatening irAE are therefore critical to the outcome of patients with immune-related neutropenia.

Methods

This multicenter international retrospective study was conducted at 17 melanoma centers to evaluate the clinical characteristics, diagnostics, treatment, and outcomes of melanoma patients with grade 4 neutropenia (<500 neutrophils/µl blood) treated with ICI between 2014 and 2020. Some of these patients received metamizole in addition to ICI (ICI+/met+). Bone marrow biopsies (BMB) of these patients were compared to BMB from non-ICI treated patients with metamizole-induced grade 4 neutropenia (ICI-/met+).

Results

In total, 10 patients (median age at neutropenia onset: 66 years; seven men) with neutropenia were identified, equating to an incidence of 0.14%. Median onset of neutropenia was 6.4 weeks after starting ICI (range 1.4–49.1 weeks). Six patients showed inflammatory symptoms, including fever (n=3), erysipelas (n=1), pharyngeal abscess (n=1), and mucositis (n=1). Neutropenia was diagnosed in all patients by a differential blood count and additionally performed procedures including BMB (n=5). Nine of 10 patients received granulocyte colony-stimulating factors (G-CSF) to treat their grade 4 neutropenia. Four patients received systemic steroids (including two in combination with G-CSF, and one in combination with G-CSF and additional ciclosporin A). Four patients were treated with one or more antibiotic treatment lines, two with antimycotic treatment, and one with additional antiviral therapy. Five patients received metamizole concomitantly with ICI. One fatal outcome was reported. BMB indicated a numerically lower CD4+ to CD8+ T cells ratio in patients with irNeutropenia than in those with metamizole-induced neutropenia.

Conclusion

Grade 4 neutropenia is a rare but potentially life-threatening side effect of ICI treatment. Most cases were sufficiently managed using G-CSF; however, adequate empiric antibiotic, antiviral, and antimycotic treatments should be administered if neutropenic infections are suspected. Immunosuppression using corticosteroids may be considered after other causes of neutropenia have been excluded.

Oxidative damage of canine erythrocytes after treatment with non-steroidal anti-inflammatory drugs

OBJECTIVE

To investigate oxidative erythrocyte damage in dogs treated with different non-steroidal anti-inflammatory drugs.

MATERIAL AND METHODS

Case-controlled prospective observational study using blood obtained from dogs presenting for lameness examinations or standard surgical procedures to a private referral clinic. Sampling was performed from April 2018 to July 2019. Groups comprised dogs receiving either metamizole (dipyrone) (22 dogs), carprofen (20 dogs) or meloxicam (20 dogs) for a minimum of 10 days. Dogs with gastrointestinal hemorrhage were excluded from the study. A complete hematological, as well as a basic biochemical profile were performed in every dog. Pappenheim stained blood smears were evaluated for eccentrocytes and brilliant cresyl blue stained smears for Heinz bodies. EDTA blood was frozen at -80°C immediately after sampling for measurement of superoxide dismutase and gluthathione peroxidase activity at an external laboratory. Hemoglobin concentration, superoxide dismutase and gluthathione peroxidase activities, reticulocyte count, eccentrocyte and Heinz body numbers were determined prospectively as key parameters for further statistical assessment with Kruskal-Wallis test and Dunn's multiple comparisons test.

RESULTS

Dogs receiving metamizole showed a significant increase in eccentrocyte (median 14.5/500 cells vs. 0/500 cells in the other groups, p < 0.0001) and reticulocyte number (median 191.4 × 10⁹/l vs. 31.6-37.9 × 10⁹/l, p < 0.0001) and a significant decrease in hemoglobin concentration (median 8.4 mmol/l vs. 10.1-10.5 mmol/l, p < 0.0003). No significant difference in superoxide dismutase and gluthathione peroxidase activities was observed between dogs receiving metamizole and the other groups. Heinz bodies were not found in any of the dogs.

CONCLUSION

Treatment with metamizole for 10 or more days resulted in decreased hemoglobin concentration, eccentrocytosis and reticulocytosis in dogs in this study. This might be a sign of increased oxidative damage caused by this drug.

CLINICAL SIGNIFICANCE

Prolonged metamizole therapy should be evaluated critically in patients already affected by severe illness or underlying anaemia.

Efficacy of metamizole versus ibuprofen and a short educational intervention versus standard care in acute and subacute low back pain: a study protocol of a randomised, multicentre, factorial trial (EMISI trial)

INTRODUCTION

Low back pain (LBP) is among the top three most common diseases worldwide, resulting in a life with pain-related disability. To date, no study has assessed the efficacy of metamizole (dipyrone), a non-opioid analgesic and antipyretic prodrug compared with the conventional non-steroidal anti-inflammatory drug ibuprofen, in patients with an acute LBP episode. Further, it is unclear, whether a short educational intervention is superior to usual care alone.

OBJECTIVES

The objective of this study is to assess first, whether metamizole is non-inferior to ibuprofen in a new episode of acute or subacute LBP. Second, we aim to assess whether a short educational intervention including evidence-based patient information on the nature of LBP is superior to usual care alone.

METHODS AND ANALYSIS

An investigator-initiated multicentre, randomised, double blind trial using a factorial design will be performed. A total of 120 participants with a new episode of LBP will be recruited from GP practices, outpatient clinics and from emergency departments, and randomised into four different treatment groups: ibuprofen alone, ibuprofen and short intervention, metamizole alone, metamizole and short intervention. The primary endpoint for the medical treatment will be change in pain assessed on an 11-point Numeric Rating Scale after 14 days. The primary outcome for the short intervention will be change in the Core Outcome Measures Index assessed after 42 days.

ETHICS, DISSEMINATION AND FUNDING

This study has been approved by the responsible Ethics Board (Ethikkommission Bern/2018-01986) and the Swiss Agency for Therapeutic Products (Swissmedic/2019DR4002). Results will be published in open access policy peer-reviewed journals. The study is funded by the Swiss National Science Foundation (grant number 32 003B-179346).

TRIAL REGISTRATION NUMBER

NCT04111315.

Pain management in hemophilia: expert recommendations

INTRODUCTION

As a typical consequence of bleeding into muscles and joints, patients with severe hemophilia suffer from acute and chronic pain. In spite of its high prevalence, pain in this patient group is not always sufficiently considered or treated in an effective manner.

AIM

The recommendations presented in this paper address possible improvements in pain management in hemophilia patients and particularities that have to be taken into account in this patient group.

METHOD

The manifold aspects of pain management in hemophilia patients were discussed within the framework of an expert meeting. Based on the available literature and the experts' clinical experience, the participants developed a set of recommendations presented in this paper.

RESULTS

Pain management in patients with hemophilia is often insufficient, a fact that not only influences the patients' quality of life but also implies the risk of difficult to manage chronic pain. Both the prevalent polypharmacy (due to comorbidities) as well as the underlying disease itself present special challenges to pain therapy in this patient group. The present review and recommendations are intended to support medical professionals in recognising the risks of pain chronicity, applying basic principles of multimodal pain therapy, including the options of psychological intervention and modalities of physical medicine in therapy concepts, and reaching a comprehensive understanding of the range of analgesic options available.

Assessment of the cytoprotective effect of the homeopathic compound Canova® on African green monkey kidney (VERO) cell line exposed to the drug dipyrone sodium

Dipyrone or metamizole is one of the most frequently used analgesic worldwide. Despite its widespread use, this drug may exert genotoxic and cytotoxic effects on lymphocytes. Therefore, studies with therapeutic agents that may provide protection against these effects are important. The homeopathic compound Canova® (CA) appears to be a beneficial candidate for preventing DNA damage and cellular lethality, since this compound acts as an immunomodulator associated with cytoprotective actions. Hence, the aim of the present investigation was to determine the potential cytoprotective effects of CA using cell line VERO as a model. VERO cells were incubated with sodium dipyrone and subsequently subject to the comet, apoptosis and immunocytochemistry assays. Data demonstrated that sodium dipyrone induced an increase in DNA damage index (DI) employing the comet assay. However, when VERO cells were co-treated with CA at the three concentrations studied, a significant reduction in DI was observed, indicating an antigenotoxic effect attributed to CA. Further dipyrone induced an elevation in %apoptosis at 24 and 48 hr. However, when dipyrone was co-incubated with CA, a significant reduction in %apoptosis was noted at the three concentrations of CA employed. Results from immunocytochemical analysis showed a rise in the expression of caspase 8 and cytochrome C when cells were exposed to dipyrone. In contrast, co-treatment of dipyrone and CA significantly reduced the effect of dipyrone. Therefore, evidence indicated that CA acted as an anticytotoxic and antigenotoxic agent counteracting damage induced by dipyrone.

Comprehensive management of adults with chronic migraine: Clinical practice guidelines in Mexico

Introduction:

Migraine is a polygenic multifactorial disorder with a neuronal initiation of a cascade of neurochemical processes leading to incapacitating headaches. Headaches are generally unilateral, throbbing, 4–72 h in duration, and associated with nausea, vomiting, photophobia, and sonophobia. Chronic migraine (CM) is the presence of a headache at least 15 days per month for ≥3 months and has a high global impact on health and economy, and therapeutic guidelines are lacking.

Methods:

Using the Grading of Recommendations, Assessment, Development, and Evaluations system, we conducted a search in MEDLINE and Cochrane to investigate the current evidence and generate recommendations of clinical practice on the identification of risk factors and treatment of CM in adults.

Results:

We recommend avoiding overmedication of non-steroidal anti-inflammatory drugs (NSAIDs); ergotamine; caffeine; opioids; barbiturates; and initiating individualized prophylactic treatment with topiramate eptinezumab, galcanezumab, erenumab, fremanezumab, or botulinum toxin. We highlight the necessity of managing comorbidities initially. In the acute management, we recommend NSAIDs, triptans, lasmiditan, and gepants alone or with metoclopramide if nausea or vomiting. Non-pharmacological measures include neurostimulation.

Conclusions:

We have identified the risk factors and treatments available for the management of CM based on a grading system, which facilitates selection for individualized management.

[Acute Abdominal Pain in the Emergency Department]

Abdominal pain is a common leading symptom in emergency medicine. This symptom complex includes a variety of different causes, ranging from intra-abdominal to extra-abdominal and retroperitoneal pathologies, which can affect all age groups. Abdominal complaints can include diseases ranging from trivialities to life-threatening emergencies. The acute abdominal condition is an interdisciplinary emergency in which interdisciplinary teamwork is mandatory. A rapid initial assessment and risk stratification is necessary in order to detect critically ill patients with an acute need for intervention at an early stage and to provide them with a suitable emergency therapy. A structured approach can identify the most important differential diagnoses.

Tilidine and dipyrone (metamizole) in cold pressor pain: A pooled analysis of efficacy, tolerability, and safety in healthy volunteers

The cold pressor test (CPT) is widely implemented and offers a simple, experimental acute pain model utilizing cold pain. Previous trials have frequently paired the CPT with opioids in order to investigate the mechanisms underlying pharmacological analgesia, due to their known analgesic efficacy. However, opioid side effects may lead to unblinding and raise concerns about the safety of the experimental setting. Despite the established clinical efficacy of dipyrone (metamizole), its efficacy, tolerability, and safety in cold pressor pain has not been systematically addressed to date. This pooled analysis included data of 260 healthy volunteers from three randomized, placebo‐controlled, double‐blind substudies using the CPT following a pre‐test‐post‐test‐design. These substudies allow for comparing a single dose of 800 mg dipyrone with two different doses of the opioid tilidine/naloxone (50/4 mg and 100/8 mg, respectively). Outcomes included pain intensity ratings, pain tolerance, medication‐attributed side effects, as well as changes of blood pressure and heart rate. We demonstrate that both opioid doses and dipyrone had a comparable, significant analgesic effect on cold pressor pain. However, dipyrone was associated with significantly less self‐reported adverse effects and these were not significantly different from those under placebo. These results indicate that the combination of dipyrone and the CPT provides a safe, tolerable, and effective experimental model for the study of pharmacological analgesia. In combination with a CPT, dipyrone may be useful as a positive control, or baseline medication for the study of analgesic modulation.

Drug dosing using estimated glomerular filtration rate: Misclassification due to metamizole interference in a creatinine assay

BACKGROUND

The estimated glomerular filtration rate is a rather important measurement for patients under intensive care, since they often receive several drugs, and impaired renal function may result in misleading dosing. The estimated glomerular filtration is derived from mathematical models using serum creatinine, a measurement that suffers interference of some drugs, such as metamizole. This study intended to evaluate the impact on patient stratification for dose adjustment of two antimicrobials (meropenem and vancomycin) caused by metamizole interference in creatinine measurement by dry chemistry.

METHODS

A cross-sectional study was conducted with a group of 108 hospitalized patients under metamizole prescriptions at fixed intervals. Serum creatinine concentrations were determined by enzymatic dry chemistry and Jaffé assays, and the estimated glomerular filtration rate was calculated through the CKD-EPI equation. Patients were stratified in groups according to their estimated glomerular filtration rate for drug dosing of vancomycin and meropenem.

RESULTS

Creatinine values were significantly lower in measurements performed by the dry chemistry method in comparison to Jaffé assay (P < 0.0001) when patients are under metamizole treatment. A significant bias (-40.3%) was observed between those two methods, leading to a significant difference (P < 0.0001) in patient classification according to renal function using the CKD-EPI equation for dosing adjustment.

CONCLUSIONS

During the validity of metamizole treatment, the stratification for drug dosing by the estimated glomerular filtration rate is not reliable if the creatinine measurement is done through dry chemistry. Clinical and laboratory staff must be aware of these limitations and cooperate to optimize pharmacotherapy.

Metamizole-Induced Type I Kounis Syndrome

Kounis syndrome (KS) is defined as acute coronary syndrome (ACS) triggered by mast cell and platelet activation in the setting of allergic or anaphylactic insults. KS is a unique and complex cause of ACS and many cases may be missed due to its highly variable clinical manifestations. In this report, we present a case of KS type I triggered by metamizole in the absence of a previous history of allergy to this drug. Following the administration of metamizole, the patient developed generalized acute urticaria, chest pain and diaphoresis. Electrocardiography (ECG) showed ST-segment elevation suggestive of myocardial infarction complicated by ventricular tachycardia. No coronary disease was observed on coronary angiography. The cardiac manifestations of KS may be life-threatening, and so it is important to appropriately recognize and treat this condition.

LEARNING POINTS

Kounis syndrome (KS) diagnosis requires a high index of suspicion and should be considered in patients who present with acute coronary syndrome (ACS) soon after the administration of a new medication or possible allergic stimulus.Treatment should be administered carefully, since some drugs used to treat the cardiac manifestations of KS can worsen the allergic reaction.The prognosis is generally good with appropriate treatment, but some complications may occur, such as malignant arrhythmia.

Dipyrone as pre-emptive measure in postoperative analgesia after tonsillectomy in children: a systematic review

INTRODUCTION

Tonsillectomy is the 2nd most common outpatient surgery performed on children in the United States of America. Its main complication is pain, which varies in intensity from moderate to severe. Dipyrone is one of the most widely used painkillers in the postoperative period in children. Its use, however, is controversial in the literature, to the point that it is banned in many countries due to its potential severe adverse effects. Because of this controversy, reviewing the analgesic use of dipyrone in the postoperative period of tonsillectomy in children is essential.

OBJECTIVE

The aim of this study was to review the analgesic use of dipyrone in the postoperative period of tonsillectomy in children.

METHODS

Systematic review of the literature, involving an evaluation of the quality of articles in the databases MEDLINE/Pubmed, EMBASE and Virtual Health Library, selected with a preestablished search strategy. Only studies with a randomised clinical trial design evaluating the use of dipyrone in the postoperative period of tonsillectomy in children were included.

RESULTS AND CONCLUSION

Only 2 randomised clinical trials were found. Both compared dipyrone, paracetamol, and placebo. We were unable to carry out a metanalysis because the studies were too heterogenous (dipyrone was used as pre-emptive analgesic in one and only postoperatively in another). The analgesic effect of dipyrone, measured by validated pain scales in childhood, was shown to be superior to placebo and similar to paracetamol. It appears that dipyrone exhibits a profile suitable for use in children. However, the scarcity of randomised clinical trials evaluating its analgesic effect in this age group leads to the conclusion that more well-designed studies are still needed to establish the role of dipyrone in the postoperative period of tonsillectomy in children.

[Analgesia for trauma patients in emergency medicine]

Adequate analgesia is one of the most important measures of emergency care in addition to treatment of vital function disorders and, if indicated, should be promptly undertaken; however, a large proportion of emergency patients receive no or only inadequate pain therapy. The numeric rating scale (NRS) is recommended for pain assessment but is not applicable to every group of patients; therefore, vital signs and body language should be included in the assessment. Pain therapy should reduce the NPRS to <5 points. Ketamine and fentanyl, which have an especially rapid onset of action, and also morphine are suitable for analgesia in spontaneously breathing patients. Basic prerequisites for safe and effective analgesia by healthcare professionals are the use of adequate monitoring, the provision of well-defined emergency equipment, and the mastery of emergency procedures. In a structured competence system, paramedics and nursing personnel can perform safe and effective analgesia.

Antinociceptive Synergy Between Metamizole and Hesperidin in a Model of Visceral Pain in Mice

BACKGROUND

Metamizole is used to relieve the visceral pain but its adverse effects limit its use. An alternative to improve its efficacy with lower doses is to combine it with a natural product as hesperidin.

AIM OF THE STUDY

The aim of this study was to evaluate the antinociceptive interaction between metamizole and hesperidin in a visceral pain model using an isobolographic analysis.

METHODS

Antinociception was evaluated in the writhing model using acetic acid (1%) to induce writhes in mice. Metamizole (1-316 mg/kg), hesperidin (3-300 mg/kg), or combinations with a fixed-dose ratio of 1:1 were administered intraperitoneally 30 min before the acetic acid and the number of writhes was counted for 30 min. Isobolographic analysis was employed to define the nature of the compound interaction.

RESULTS

Metamizole and hesperidin in individual administration induced dose-dependent antinociceptive effects, reached an efficacy of 84.2 ± 5.9% and 66.3 ± 7.4%, respectively. The ED₅₀ values calculated from their dose-response curves were 84.5 ± 22.7 and 108.9 ± 17.9 mg/kg, respectively. The analysis of DRC for the metamizole + hesperidin combination, in a ratio 1:1 showed a ED_{50 COMB} value lower than the ED_{50 ADD} estimated from the additivity line from the isobologram (46.7 ± 6.3 vs. 96.7 ± 11.9 mg/kg, respectively). In addition, the pharmacological interaction calculated was of 0.48. These results suggest a synergistic interaction for the antinociceptive activity of metamizole + hesperidin combination.

CONCLUSION

These data suggest that metamizole + hesperidin combination could be useful in treating visceral pain as it can interact synergistically using low dose of both drugs with the possibility of reducing the risk of adverse effects.

Triazol-phenyl antipyretic derivatives inhibit mPGES-1 mRNA levels in LPS-Induced RAW 264.7 macrophage cells

BACKGROUND

Microsomal prostaglandin E synthase-1 (mPGES-1) catalyzes the terminal step of prostaglandin E2 (PGE2) production, which plays an important role in the regulation of febrile response. In our previous work, ligand-based pharmacophore models, built with mPGES-1 inhibitors, were employed to identify a novel series of compounds that reduce the febrile response in rats.

OBJECTIVES

Evaluate the mechanism of action of the most active compound (1).

METHODS

For in vivo assays, rats were pretreated with the antipyretic compounds 1-8, 30 min before LPS injection. For in vitro assays, RAW 264.7 macrophage cells were incubated with the antipyretic compounds 1-8 for 1 hour before LPS stimu-lus. After 16 h, quantitative real-time PCR was carried out. Additionally, the PGE2 concentration in hypothalamus was quantified by ELISA and the inhibitory effect of N-cyclopentyl-N'-[3-(3-cyclopropyl-1H-1,2,4-triazol-5-yl)phenyl]ethanediamide (1) over human COX-2 enzymatic activity was determined with a COX Colorimetric Inhibitor Screening Assay Kit.

RESULTS

Compound 1 and CAY10526 have comparable efficacy to reduce the febrile response when injected i.v. (com-pound 1: 63.10%, CAY10526: 70.20%). Moreover, compound 1 significantly reduces the mPGES-1 mRNA levels, in RAW264.7 cells, under inflammatory conditions. A chemically-similar compound (8- ) also significantly reduces the mRNA levels of the gene target. On the other hand, compounds 6 and 7, which are also somewhat similar to compound 1, do not, significantly, impact mPGES-1 mRNA levels.

CONCLUSIONS

PGE2 concentration reduction in hypothalamus, due to compound 1 central injection, is related to decreased mPGES-1 mRNA levels but not to COX-2 inhibition (IC50> 50 μM). Therefore, compound 1 is a promising lead for inno-vative antipyretic drug development.

Cyclooxygenases 1 and 2 inhibition and analgesic efficacy of dipyrone at different doses or meloxicam in cats after ovariohysterectomy

OBJECTIVE

To evaluate the cyclooxygenases (COX) inhibition, adverse effects and analgesic efficacy of dipyrone or meloxicam in cats undergoing elective ovariohysterectomy.

STUDY DESIGN

Prospective, blinded, randomized, clinical study.

ANIMALS

A total of 30 healthy young cats.

METHODS

The cats were randomly assigned to three postoperative groups: D25 (dipyrone 25 mg kg^-1 every 24 hours), D12.5 (dipyrone 12.5 mg kg^-1 every 12 hours) and M (meloxicam 0.1 mg kg^-1 every 24 hours). In the first 24 hours, the drugs were administered intravenously (IV), and then orally for 6 (dipyrone) or 3 days (meloxicam). Prostanoids thromboxane B₂ and prostaglandin E₂ concentrations served as indicators of COX activity and, with physiological variables and pain and sedation scores, were measured for 24 hours after first analgesic administration. Rescue analgesia (tramadol, 2 mg kg^-1 IV) was provided if Glasgow feline composite measure pain scale (CMPS-Feline) ≥5. Laboratory tests included symmetric dimethylarginine and adverse effects were evaluated regularly up to 7 and 10 days after surgery, respectively. Parametric and nonparametric data were analyzed with two-way anova and Kruskal-Wallis tests, respectively (p < 0.05).

RESULTS

In the first half hour after analgesic administration, COX-1 activity was close to zero and remained significantly lower than before drug administration for 24 hours in all groups. The inhibition of COX-2 activity was significant for 30 minutes in all groups and up to 4 hours in group M. No alterations in laboratory tests or significant adverse effects were observed. Pain scores and need for rescue analgesia did not differ statistically among groups.

CONCLUSIONS

Dipyrone at both doses and meloxicam provided a nonselective inhibition of COX-1 and -2 activities and effective analgesia without causing significant adverse effects or laboratory tests alterations.

CLINICAL RELEVANCE

Dipyrone at both doses provides equally effective analgesia without causing adverse effects in cats undergoing ovariohysterectomy.

[Considerations concerning the perioperative use of metamizole]

BACKGROUND

The non-opioid analgesic metamizole (dipyrone) is approved for the treatment of severe pain and is often used in the perioperative period. As it can cause agranulocytosis, a severe adverse event, its perioperative administration is controversially discussed.

OBJECTIVE

Is there enough evidence for a high risk of metamizol-induced agranulocytosis (MIA)? What are the consequences of its perioperative use with respect to the risk profiles of alternative analgesics?

MATERIAL AND METHODS

Rapid review of the literature on the risk of MIA and adverse effects of non-opioid analgesics.

RESULTS

The incidence of MIA is estimated to be one case per million inhabitants per year. The risk seems low compared to other drugs associated with a risk of agranulocytosis, such as antithyroid drugs and ticlopidine. The risk profile of metamizole concerning hepatotoxicity, nephrotoxicity, bleeding and cardiovascular adverse effects is favorable compared to other non-opioid analgesics. None of the non-opioid analgesics are licensed to be administered intraoperatively.

CONCLUSION

The perioperative use of metamizole is possible after a thorough evaluation of the indications as it provides good analgesia with a generally favorable side effect profile and is administered intravenously. The risk of agranulocytosis is small but needs to be mentioned during patient informed consent in order to optimize early recognition. Intraoperative administration aims at reducing the expected severe postoperative pain. A documentation and justification for the evaluation of the indications are recommended.

[Pain and pain management in old age: special features and recommendations]

INTRODUCTION

Pain is highly prevalent in older persons and has a variety of causes. In geriatric patients, especially in patients with dementia, pain is often not sufficiently recognized and therefore frequently remains untreated. For the affected patient group this can have far-reaching consequences for their functional and cognitive abilities and may consequently lead to loss of autonomy.

OBJECTIVE

Existing deficits of pain assessment for geriatric patients are described, with a primary focus on those patients suffering from cognitive impairments and pain. In addition, the influence of multimorbidity on pain management in old age is considered in detail.

METHODS

The diagnostics and measurement of pain in older individuals are described based on recent literature and corresponding instruments used in the assessment of pain are outloned. The authors pay special attention to the possibilities of pain measurement in patients with higher grade cognitive impairments and non-communicative patients.

CONCLUSION

A standardized pain assessment should be an integral component in the care and treatment of geriatric patients and individuals suffering from dementia. Validated instruments for pain measurement exist for both groups and should be integrated into daily clinical practice.

Development of electroanalytical procedure for monitoring of metamizole in organic fertilizers (human urine and struvite) associated with portable equipment

Urine and struvite are promising organic fertilizers that can replace conventional fertilizers. However, these fertilizers can have some emerging contaminants, such as dipyrone. This drug is one of the main painkillers consumed in the world and its continuous and indiscriminate intake can promote the camouflage of symptoms of other diseases, anaphylactic shock and even death. Thus, a fast, sensitive, inexpensive and portable method for metamizole (dipyrone) determination in several matrices, applied as organic fertilizers, has been successfully developed using portable equipment and bare carbon screen-printed electrodes in conjunction with square wave voltammetry (SWV). The main SWV operating parameters were optimized (equilibrium time (60 s), step potential (6 mV), modulation amplitude (50 mV) and frequency (10 Hz)) using univariate experiments. The proposed method presented a limit of detection of 0.097 ± 0.002 μmol L^-1 (RSD = 2.72%, n = 3) for dipyrone in 0.1 mol L^-1 HCl and R² equal to 0.993. The determination in the struvite sample presented a concentration of 0.47 μmol L^-1 of dipyrone. Urine sample used in the production of struvite and urine collected from an individual 10h after ingestion of 500 mg dipyrone tablet showed concentrations of 15.2 and 590 μmol L^-1 of dipyrone, respectively. The recovery test in fortified struvite sample showed values between 91 and 102% (RSD = 3.1%, n = 3) and of 102% (SD = 3.7%, n = 3) in human urine, indicating that there is no matrix effect. These results reinforce the possibility of applying the proposed method on-site in a practical and fast way, without the need of significant amounts of sample promoting a more sustainable chemistry.

Pain severity and analgesics use in the community-dwelling older population: a drug utilization study from Germany

Purpose

Chronic pain is common in the older population and a significant public health concern. However, comprehensive studies on analgesics use in this age group from Germany are scarce. This study aims to give a comprehensive overview on the use of the most common therapeutic groups of analgesics in community-dwelling older adults from Germany.

Methods

A cross-sectional study was carried out using data from a German cohort of 2038 community-dwelling adults aged 63–89 years. Descriptive statistics and logistic regression models were applied to assess the utilization of analgesics by age, sex, pain severity, pain duration, and locations.

Results

One out of four study participants was suffering from high-intensity or disabling pain. Approximately half of those taking analgesics still reported to suffer from high-intensity or disabling pain. Among analgesics users, occasional non-steroidal anti-inflammatory drugs (NSAIDs) use was the most frequent pain therapy (in 43.6% of users), followed by metamizole (dipyrone) use (16.1%), regular NSAIDs use (12.9%), strong opioids use (12.7%), and weak opioids use (12.0%). In multivariate logistic regression models, higher age, higher pain severity, longer pain duration, abdominal pain, and back pain were statistically significantly associated with opioids use. Metamizole use was also statistically significantly associated with higher pain severity but inversely associated with pain duration.

Conclusions

A significant number of older German adults are affected by high-intensity and disabling chronic pain despite receiving analgesics. Long-term studies are needed to compare the effectiveness and safety of different treatments for chronic pain in older adults.

Electronic supplementary material

The online version of this article (10.1007/s00228-020-02954-5) contains supplementary material, which is available to authorized users.

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.

Analgesia in acute ischemic chest pain

Analgesics, particularly opioids, have been routinely used in the emergency treatment of ischemic chest pain for a long time. In the past two decades; however, several studies have raised the possibility of the harmful effects of opioid administration. In 2014, the American Heart Association (AHA)/American College of Cardiology Foundation (ACCF) changed the guidelines regarding the use of opioids from class IC to class IIb for non-ST elevation acute coronary syndrome. And in 2015, the European Society of Cardiology (ESC) guidelines incidentally noted the side effects of opioids. In ST-segment elevation myocardial infarction, both ESC and AHA/ACCF still recommend the use of opioids. Given the need for adequate pain relief in ischemic chest pain in the emergency setting, it is necessary to understand the adverse effects of analgesia, while still providing sufficiently potent options for analgesia. The primary purpose of this review is to quantify the effects of analgesics commonly used in the prehospital and emergency department in patients with ischemic chest pain.

Metamizole: An underrated agent causing severe idiosyncratic drug-induced liver injury

Aims

Drug‐induced liver injury (DILI) is a heterogenous entity leading to liver damage. We have analysed the frequency, biochemical and histological patterns and clinical courses of DILI cases due to metamizole at our tertiary care centre in Hamburg, Germany.

Methods

Consecutive patients with DILI who presented to our clinic were analysed retrospectively. Causes of acute hepatitis other than DILI were excluded.

Results

In total, 154 DILI cases were admitted to our centre from 2008 to 2017. After phenprocoumon, metamizole was the second most frequent putative agent causing DILI (23 of all 154 DILI cases, 14,9%). The biochemical pattern on admission of metamizole‐induced DILI cases was hepatocellular with median levels of alanine transaminase (779 U/L, 64–3532 U/L) by far exceeding median alkaline phosphatase levels (131 U/L, 42–578 U/L). In 17 of the 23 cases (74%) liver biopsy was performed. Moderate to severe inflammatory histological activity and severe centrilobular necrosis (>30%) was present in 76.5 and 35.3%, respectively. Metamizole was involved in 2 DILI cases progressing to acute liver failure, then receiving liver transplantation and still alive at time of assessment. Our data were supported by re‐exposure in 4 patients. Furthermore, a database search for metamizole‐induced liver injury in the European Medicines Agency's database identified about 300 reports on suspected metamizole‐induced DILI in Europe.

Conclusion

Elevation of liver enzymes or acute liver failure are not mentioned in the German drug label of metamizole as potential side effects. Our study reveals that in Germany and Europe, metamizole is a frequent and underrated agent causing DILI.

Metamizole and the risk of drug-induced agranulocytosis and neutropenia in statutory health insurance data

The non-opioid analgesic metamizole (dipyrone) is used for the treatment of acute and chronic pain and fever. Agranulocytosis is known as a serious adverse drug reaction of metamizole with potentially fatal outcome. However, its frequency is controversially discussed. The aim of our study was to determine the risk of metamizole-associated agranulocytosis and neutropenia using statutory health insurance data. We analyzed data from a large German health insurance fund in the period from 2010 to 2013. Metamizole-exposed subjects were identified and compared to a propensity score-matched control cohort. A total of 630,285 metamizole-treated subjects and 390,830 matched control subjects were included. In the metamizole cohort, ICD codes for agranulocytosis and neutropenia appeared more often than in non-users. The relative risk for drug-induced agranulocytosis and neutropenia (D70.1) was 3.03 (95% confidence interval, 2.49 to 3.69). The risk for developing drug-induced agranulocytosis and neutropenia after metamizole prescription was 1: 1602 (CI 95%, 1:1926 to 1:1371). Our results confirm the risk estimation of previous studies. However, the outcome of our study may be confounded by an association of metamizole treatment and chemotherapy. Therefore, consequences for treatment have to be drawn with care.