Fatal pulmonary hemorrhage, pneumothorax and skin necrosis caused by IRIS to an Aspergillus flavus infection in a young patient with metamizole associated agranulocytosis.

We report the case of a young female with steroid-dependent ulcerative colitis (UC) who developed a complex systemic infection with Aspergillus flavus. This occurred following a UC relapse while vacationing in the Middle East, leading to extended use of metamizole and subsequent agranulocytosis. On her return to Germany, she was hospitalized for neutropenic sepsis and later transferred to our hospital due to persistent cytopenia and suspected Hemophagocytic Lymphohistiocytosis (HLH). Despite initial stabilization with targeted treatment for pulmonary Aspergillus flavus infection, her condition rapidly deteriorated following the onset of an Immune Reconstitution Inflammatory Syndrome (IRIS), which manifested as skin necrosis and pneumothorax after the replenishment of neutrophil granulocytes. The patient eventually died from an unmanageable pulmonary hemorrhage. Microscopy of skin necroses showed a massive presence of Aspergillus flavus, but tissue culture remained negative, suggesting effective antifungal treatment yet delayed phagocytosis due to agranulocytosis. This case underscores the need to consider IRIS in immunosuppressed patients who worsen despite aggressive and appropriately targeted treatment, highlighting its potential beyond the commonly recognized context in HIV-positive patients.

Risk of agranulocytosis with metamizole in comparison with alternative medications based on health records in Spain.

PURPOSE: We aimed to estimate the absolute (incidence) and relative (hazard ratio; HR) risk of agranulocytosis associated with metamizole in comparison with non-steroidal antiinflammatory drugs (NSAIDs). METHODS: A cohort study of new users of metamizole versus NSAIDs was performed with BIFAP (Pharmacoepidemiologic Research Database in Public Health Systems; Spain). Patients aged ≥ 2 years in 2005-2022 were followed up from the day after their first metamizole or NSAID dispensation till the end of the treatment period to identify patients hospitalized due to idiosyncratic agranulocytosis. Incidence rate (IR) and adjusted HR of agranulocytosis with metamizole versus NSAID were estimated assuming the onset date of agranulocytosis was the date of hospitalization sensitivity analysis or 7 days before (main analysis). In secondary analyses, we used (1) opioids-paracetamol as negative control and (2) any hospitalized neutropenia as outcome (assuming the onset was 7 days before). RESULTS: The cohorts included 444,972 new users of metamizole, 3,814,367 NSAID, and 3,129,221 opioids-paracetamol on continuous treatment during a median of 37-40 days. Overall, 26 hospitalized agranulocytosis occurred, 5 in the first week (and so removed in main analysis) and 21 thereafter. IR of agranulocytosis was 14.20 (N = 5 cases) and 8.52 (N = 3), 1.95 (N = 6) and 1.62 (N = 5), and 4.29 (N = 15) and 3.72 (N = 13)/107 person-weeks of continuous treatment using the date of hospitalization or 7 days before, respectively. Two, 0 and 2 of cases identified in both analyses had neoplasia in every cohort, respectively. HR of agranulocytosis associated with metamizole was 7.20 [95% CI: 1.92-26.99] and 4.40 [0.90-21.57] versus NSAID, and 3.31 [1.17-9.34] and 2.45 [0.68-8.83] versus opioid-paracetamol, respectively. HR of neutropenia with metamizole was 2.98 [1.57-5.65] versus NSAID. CONCLUSIONS: Agranulocytosis was very rare but more common (above 4 times more) with metamizole than other analgesics. The impact of the drug-induced agranulocytosis was less precise with metamizole than the comparators due to its lower use, which precluded to find statistical differences in main analysis. The increased risk of hospitalized neutropenias with metamizole supports the link with its severity although triggers unavailable during the follow-up (ex. cytotoxic medication) can not be discarded.

Increased Use and Large Variation in Strong Opioids and Metamizole (Dipyrone) for Minor and Major Musculoskeletal Injuries Between 2008 and 2018: An Analysis of a Representative Sample of Swiss Workers.

PURPOSE: Musculoskeletal (MSK) injuries are a major contributing factor for chronic pain. To date, little is known how pain medication use in MSK injuries has changed over time. We assessed pain medication prescription for MSK injuries in a representative sample of Swiss workers between 2008 and 2018. METHODS: Retrospective analysis of the Swiss Accident Insurance Fund (Suva) data. We calculated annual pain medication use, treatment days, and costs associated with pain medication use in minor and major MSK injuries. RESULTS: In total, 1,921,382 cases with MSK injuries with ≥ 1 pain medication were analyzed. Whereas MSK injuries with ≥ 1 pain medication increased by 9.4%, we observed a larger increase in metamizole (+ 254%), strong opioids (+ 88.4%), coxibs (+ 85.8%), and paracetamol (+ 28.1%). Strong opioids were increasingly used in minor (+ 91.4%) and major (+ 88.3%) injuries. The increase in metamizole (+ 390.6%) and coxibs (+ 115.5%) was larger in minor injuries compared to major injuries (+ 238.7% and + 80.6%, respectively). Medical expenses decreased in all medications except for strong opioids where a substantial increase was observed (+ 192.4% in minor; + 34% in major injuries). CONCLUSIONS: We observed a disproportionate increase in metamizole, strong opioids, coxibs, and paracetamol prescriptions even in minor MSK injuries between 2008 and 2018. Whereas treatment costs decreased for all pain medications, there was a substantial increase in strong opioids. A more liberal prescription practice of opioids conflict with current evidence-based practice recommendations and need to be addressed by physicians and policy makers.

Management of analgesia in acute pancreatitis: Results of a national survey. / Manejo de la analgesia en la pancreatitis aguda. Resultados de una encuesta nacional.

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.

Time course of CYP3A activity during and after metamizole (dipyrone) in healthy volunteers.

AIMS: In patients of all ages, metamizole is a frequently used analgesic. Recently, metamizole has been identified as an inducer of, among others, cytochrome P450 (CYP) 3A activity, but the time course of this interaction has not been evaluated. METHODS: Using repeated oral microdoses (30 µg) of the CYP3A index substrate midazolam, we assessed changes in midazolam pharmacokinetics (area under the concentration-time curve from 2-4 h: AUC2-4 and estimated partial metabolic clearance: eClmet ) before, at steady-state, and after discontinuation of 3 × 1000 mg metamizole/day orally for 8 days. RESULTS: Significant changes in pharmacokinetic parameters were detected already 3 days after start of metamizole treatment. At the steady-state of enzyme induction, the geometric mean ratio of midazolam AUC2-4 was substantially reduced to 0.18 (90% confidence interval: 0.14-0.24) with a corresponding 5.43-fold (4.15-7.10) increase of eClmet . After discontinuation of metamizole, the changes slowly recovered, but were still significant at the end of the observation period on the fifth day after discontinuation of metamizole therapy (AUC2-4 reduced to 0.50 [0.41-0.63] and eClmet 1.99-fold increased [1.60-2.47, P < 0.05]). CONCLUSION: Metamizole acts as a strong inducer of CYP3A already few days after start of metamizole administration and, thus, should be avoided in patients using drugs with narrow therapeutic index and major clearance via CYP3A. If their administration is essential, close monitoring and dose adjustment of comedication should be performed as early as the first week after the initiation and after discontinuation of metamizole therapy.

A case of chronic disseminated candidiasis in metamizole-induced neutropaenia.

Chronic disseminated candidiasis (CDC) is a severe complication of a disseminated yeast infection mainly seen after prolonged chemotherapy-induced neutropaenia in the context of haematological malignancy. We present a case of CDC in a patient with metamizole-induced neutropaenia. To the best of our knowledge, this is the first case described in this context. Furthermore, we highlight the role of steroids in the management of this disease.

Effect of the combination of diuretics, renin-angiotensin-aldosterone system inhibitors, and non-steroidal anti-inflammatory drugs or metamizole (triple whammy) on hospitalisation due to acute kidney injury: A nested case-control study.

PURPOSE: Concomitant use of diuretics, renin-angiotensin-aldosterone system (RAAS) inhibitors, and non-steroidal anti-inflammatory drugs (NSAIDs) or metamizole, known as 'triple whammy' (TW), has been associated with an increased risk of acute kidney injury (AKI). Nevertheless, there is still uncertainty on its impact in hospitalisation and mortality. The aim of the study was to analyse the association between exposure to TW and the risk of hospitalisation for AKI, all-cause mortality and the need for renal replacement therapy (RRT). METHODS: A case-control study nested in a cohort of adults exposed to at least one diuretic or RAAS inhibitor between 2009 and 2018 was carried out within the Pharmacoepidemiological Research Database for Public Health Systems (BIFAP). Patients hospitalised for AKI between 2010 and 2018 (cases) were matched with up to 10 patients of the same age, sex and region of Spain who had not been hospitalised for AKI as of the date of hospitalisation for AKI of the matching case (controls). The association between TW exposure versus non-exposure to TW and outcome variables was analysed using logistic regression models. RESULTS: A total of 480 537 participants (44 756 cases and 435 781 controls) were included (mean age: 79 years). The risk of hospitalisation for AKI was significantly higher amongst those exposed to TW [adjusted odds ratio (aOR) 1.36, 95% confidence interval (95%CI) 1.32-1.40], being higher with current (aOR 1.60, 95%CI 1.52-1.69) and prolonged exposure (aOR 1.65, 95%CI 1.55-1.75). No significant association was found with the need of RRT. Unexpectedly, mortality was lower in those exposed to TW (aOR 0.81, 95%CI 0.71-0.93), which may be influenced by other causes. CONCLUSION: Vigilance should be increased when diuretics, RAAS inhibitors, and NSAIDs or metamizole are used concomitantly, especially in patients at risk such as elderly patients.

Additive or synergistic analgesic effect of metamizole on standard pain treatment at home after arthroscopic shoulder surgery: A randomised controlled superiority trial.

BACKGROUND: There is growing evidence that the analgesic effect of metamizole is mediated at least partly by central mechanisms, including the endocannabinoid/endovanilloid system. Consequently, metamizole may have additive or even synergistic analgesic effects with paracetamol and nonsteroidal anti-inflammatory drugs (NSAID). OBJECTIVE: This study aimed to assess if triple therapy with metamizole, ibuprofen and paracetamol (MIP) is superior to double therapy with ibuprofen and paracetamol (i.p.) in treating pain at home after ambulatory arthroscopic shoulder surgery. DESIGN/SETTING/PATIENTS/INTERVENTION: In this double-blind, controlled, high-volume single centre, superiority trial, 110 patients undergoing elective ambulatory arthroscopic shoulder surgery were randomised to receive either MIP ( n  = 55) or i.p. ( n  = 55) orally for 4 days between December 2019 and November 2021. Pain intensity at movement and rest, using a numeric rating scale (NRS), perceived pain relief, use of rescue medication and adverse effects of study medication were recorded at the post-anaesthesia care unit (PACU) and on postoperative day (POD) 1 to 4 and 7. Quality of Recovery (QoR) and satisfaction with study medication were measured at POD 7 with telephone follow-up. MAIN OUTCOME MEASURE: The primary outcome measure was postoperative pain intensity on movement measured by an 11-point NRS (where 0 = no pain and 10 = worst pain imaginable) on POD 1. RESULTS: For the primary outcome, superiority of MIP in reducing postoperative pain at movement on POD 1 was not confirmed: mean difference NRS [95% confidence interval (CI), -0.08 (-1.00 to 0.84)]. For pain on movement and at rest, no significant differences were found between groups in the PACU nor on POD 1 to 4 or day 7. Nausea was reported significantly more frequently in the metamizole group (22.6 vs. 58.5; P  < 0.001). Other adverse effects of study medication, rescue opioid consumption, perceived pain relief, QoR at POD 7, and overall patient satisfaction were similar in both groups. CONCLUSION: Clinically, triple oral treatment with metamizole, paracetamol and ibuprofen is not superior to oral paracetamol and ibuprofen in multimodal pain treatment at home after ambulatory arthroscopic shoulder surgery. TRIAL REGISTRATION: European Union Clinical Trials Register 2019-002801-23 and Clinicaltrials.gov NCT04082728.

Use of meloxicam with or without dipyrone in non-surgical embryo recovery in hair sheep: Effects on animal welfare.

The aim of this study was to determine the effectiveness of meloxicam with or without dipyrone on the welfare of ewes subjected to non-surgical embryo recovery (NSER). Two studies were carried out using 51 multiparous Santa Inês ewes. All animals received a standard oestrous synchronization treatment and a superovulatory protocol. In Study 1, 12 ewes received meloxicam (GM) before cervical transposition (1 mg kg-1 , i.v.), repeated 24 h after (1 mg kg-1 , i.m.), while the other 10 received a saline solution, remaining as a control group (GC1). In Study 2, ewes were allocated into a group of 15 ewes treated as GM of Study 1 associated with dipyrone (GMD; 50 mg kg-1 , i.m.) before cervical transposition, 12 h, and 24 h after, or a control group (GC2) of 14 ewes treated with saline solution. In both studies, heart and respiratory rates (RR), cortisol, glucose, total proteins, albumin and globulins blood concentration were recorded before sedation (BS), after sedation (AS), after cervical transposition, immediately after collection (IAC), and 0.5, 1.5, 3, 6, 12, 24 and 48 h after embryo collection (hAC). In Study 1, RR tended to be greater in GC1 (p = .08), serum total proteins and globulins values were lower and serum albumin values were greater in this group than GM (p = .003, p < .0001, and p < .0001, respectively). In Study 2, treatment of GMD tended to reduce the glycaemia at AS (p = .052) and reduced it at 3hAC (p < .0001), and 6hAC (p = .03). It also tended to reduce cortisol concentrations (p = .10). The other variables varied with NSER without interaction with the experimental treatments. In conclusion, in this study condition, NSER in sheep induced transient changes indicative of stress and possibly pain, therefore, affecting animal welfare. The administration of meloxicam was ineffective to reduce those responses, and the association of dipyrone had only slight effects without modifying the main welfare indicative responses in ewes subjected to NSER.

Application of analgesics in emergency services in Germany: a survey of the medical directors.

ABSTRAC: BACKGROUND: Treatment of acute pain is an essential element of pre-hospital care for injured and critically ill patients. Clinical studies indicate the need for improvement in the prehospital analgesia. OBJECTIVE: The aim of this study is to assess the current situation in out of hospital pain management in Germany regarding the substances, indications, dosage and the delegation of the use of analgesics to emergency medical service (EMS) staff. MATERIAL AND METHODS: A standardized survey of the medical directors of the emergency services (MDES) in Germany was carried out using an online questionnaire. The anonymous results were evaluated using the statistical software SPSS (Chi-squared test, Mann-Whitney-U test). RESULTS: Seventy-seven MDES responsible for 989 rescue stations and 397 EMS- physician bases in 15 federal states took part in this survey. Morphine (98.7%), Fentanyl (85.7%), Piritramide (61%), Sufentanil (18.2%) and Nalbuphine (14,3%) are provided as opioid analgesics. The non-opioid analgesics (NOA) including Ketamine/Esketamine (98,7%), Metamizole (88.3%), Paracetamol (66,2%), Ibuprofen (24,7%) and COX-2-inhibitors (7,8%) are most commonly available. The antispasmodic Butylscopolamine is available (81,8%) to most rescue stations. Fentanyl is the most commonly provided opioid analgesic for treatment of a traumatic pain (70.1%) and back pain (46.8%), Morphine for visceral colic-like (33.8%) and non-colic pain (53.2%). In cases of acute coronary syndrome is Morphine (85.7%) the leading analgesic substance. Among the non-opioid analgesics is Ketamine/Esketamine (90.9%) most frequently provided to treat traumatic pain, Metamizole for visceral colic-like (70.1%) and non-colic (68.6%) as well as back pain (41.6%). Butylscopolamine is the second most frequently provided medication after Metamizole for "visceral colic-like pain" (55.8%). EMS staff (with or without a request for presence of the EMS physician on site) are permitted to use the following: Morphine (16.9%), Piritramide (13.0%) and Nalbuphine (10.4%), and of NOAs for (Es)Ketamine (74.1%), Paracetamol (53.3%) and Metamizole (35.1%). The dosages of the most important and commonly provided analgesic substances permitted to independent treatment by the paramedics are often below the recommended range for adults (RDE). The majority of medical directors (78.4%) of the emergency services consider the independent application of analgesics by paramedics sensible. The reason for the relatively rare authorization of opioids for use by paramedics is mainly due to legal (in)certainty (53.2%). CONCLUSION: Effective analgesics are available for EMS staff in Germany, the approach to improvement lies in the area of application. For this purpose, the adaptations of the legal framework as well as the creation of a guideline for prehospital analgesia are useful.

The effects of metamizole on hematopoietic progenitor cells: Suppression of hematopoiesis stimulation in vitro.

BACKGRAUND: There is evidence that the adverse effects of metamizole occur due to the effect of the drug on the hematopoietic stem/progenitor cells, and therefore, the disruption of hematopoiesis. Therefore, our study aimed to evaluate the effects of metamizole on hematopoietic stem/progenitor cells using cell culture techniques. MATERIAL AND METHODS: In our study, samples were taken from stem cell products of healthy allogeneic stem cell transplant donors. The colony-forming unit (CFU) assay was used for the cells obtained from these samples. In addition, the drug effects on cell proliferation were evaluated with the MTT. Furthermore, the cell colonies were labelled with immunofluorescent antibodies and the effects of metamizole on cell types formed in culture were evaluated. RESULTS: We determined that metamizole negatively affects the proliferation of cells, especially starting from 10 µM. As a result of the evaluation of colonization, we saw that the number of colonies decreased with increasing concentrations. Granulocyte-macrophage colonies were more affected at increasing concentrations than other colonies. As a result of the evaluations of our in vitro study, it was also shown as an important finding that the individual effects of the drug were highly variable. CONCLUSION: CFU method can be used as a suitable method to investigate the effects of drugs and toxic substances on hematopoiesis. We also think it may be suitable for pre-analysing hematopoietic side effects in new drug research. In addition, using stem cell samples in studies may contribute more easily to the in vitro simulation of hematopoietic differentiations (Fig. 7, Ref. 29). Text in PDF www.elis.sk Keywords: metamizole, hematopoietic progenitor cells, hematopoiesis, CFU assay, adverse effect.

Cytochrome P450 1A2 is the most important enzyme for hepatic metabolism of the metamizole metabolite 4-methylaminoantipyrine.

AIMS: Metamizole (dipyrone) is a prodrug not detectable in serum or urine after oral ingestion. The primary metabolite, 4-methylaminoantipyrine (4-MAA), can be N-demethylated to 4-aminoantipyrine (4-AA) or oxidized to 4-formylaminoantipyrine (4-FAA) by cytochrome P450 (CYP)-dependent reactions. We aimed to identify the CYPs involved in 4-MAA metabolism and to quantify the effect of CYP inhibition on 4-MAA metabolism. METHODS: We investigated the metabolism of 4-MAA in vitro using CYP expressing supersomes and the pharmacokinetics of metamizole in the presence of CYP inhibitors in male subjects. RESULTS: The experiments in supersomes revealed CYP1A2 as the major CYP for 4-MAA N-demethylation and 4-FAA formation with CYP2C19 and CYP2D6 contributing to N-demethylation. In the clinical study, we investigated the influence of ciprofloxacin (CYP1A2 inhibitor), fluconazole (CYP2C19 inhibitor) and the combination ciprofloxacin/fluconazole on the pharmacokinetics of metamizole in n = 12 male subjects in a randomized, placebo-controlled, double-blind study. The geometric mean ratios for the area under the concentration-time curve of 4-MAA after/before treatment were 1.17 (90% CI 1.09-1.25) for fluconazole, 1.51 (90% CI 1.42-1.60) for ciprofloxacin and 1.92 (90% CI 1.81-2.03) for ciprofloxacin/fluconazole. Fluconazole increased the half-life of 4-MAA from 3.22 hours by 0.47 hours (95% CI 0.13-0.81, P < .05), ciprofloxacin by 0.69 hours (95% CI 0.44-0.94, P < .001) and fluconazole/ciprofloxacin by 2.85 hours (95% CI 2.48-3.22, P < .001). CONCLUSION: CYP1A2 is the major CYP for the conversion of 4-MAA to 4-AA and 4-FAA. The increase in 4-MAA exposure by the inhibition of CYP1A2 and by the combination CYP1A2/CYP2C19 may be relevant for dose-dependent adverse reactions of 4-MAA.

Design, synthesis and in vivo evaluation of 1,4-dioxo-2-butenyl aryl amine derivatives as a promising anti-inflammatory drug prototype.

Inflammation is a natural response of the organism to an infection, trauma, or cellular stress. Pain is the first symptom of acute and chronic inflammation. The standard class of medication to treat inflammatory pain is the nonsteroidal anti-inflammatory drug (NSAID). These drugs are associated with severe side effects such as gastric ulcers, gastritis, or internal bleeding. One of NSAIDs, Dipyrone® (metamizole) is largely used in many European and South American countries despite its dubious effectivity and its withdrawal from the market of several countries. Here, aiming to identify a new anti-inflammatory drug prototype based on Dipyrone® structure, a set of 27 molecules were virtually screened, and 4 compounds containing the active metabolite 4-aminoantipyrine and 1,4-dioxo-2-butenyl fragment were selected for docking, synthesis, and biological evaluation. The selection was based on the number of H-bonds and π- π stacking interactions between the inhibitor and the amino acids within the binding site of the enzyme. Carrageenan-induced paw edema, acetic acid-induced writhing, and formalin assays were used to evaluate inflammation and pain response. The selected compounds 1-4 inhibited the involvement of biogenic amines in the formation of paw edema. Compounds 1-4 also reduced pain in the inflammatory response phase. It has to be noted that 4-AA may cause agranulocytosis, which should be borne in mind when developing drug candidates of similar structure. Our new drug prototypes based on 4-aminoantipyrine and 1,4-dioxo-2-butenyl moieties open a gate for developing a prototype of nonsteroidal anti-inflammatory drugs.

Fetal adverse effects following NSAID or metamizole exposure in the 2nd and 3rd trimester: an evaluation of the German Embryotox cohort.

BACKGROUND: Non-steroidal anti-inflammatory drugs (NSAID) are frequently used to treat pain, fever and inflammatory conditions. Due to evidenced fetotoxicity, treatment with NSAID and metamizole should be avoided in the 3rd trimester of pregnancy. There is an ongoing debate on fetotoxic risk of 2nd trimester use which is why we have conducted this study. METHODS: In this observational cohort study outcome of pregnancies with NSAID and/or metamizole exposure in the 2nd and/or 3rd trimester (study cohort n = 1092) was compared with pregnancies exposed to NSAID and/or metamizole in the 1st trimester only (comparison cohort, n = 1154). The WHO-UMC system was used to assess causality between study medication and study endpoints. Prenatal study endpoints were constriction of ductus arteriosus Botalli, oligohydramnios, late spontaneous abortion (SAB) or stillbirth. Postnatal study endpoints were patent ductus arteriosus (PDA), anomalies of the right heart ventricle, primary pulmonary hypertension (PPHT), and neonatal impairment of kidney function. RESULTS: Ductus arteriosus constriction was diagnosed in 5/1092 (0.5%) in the study cohort versus 0/1154 pregnancies in the comparison cohort. In one fetus, ductus arteriosus constriction and oligohydramnios occurred already in the late 2nd trimester after long-term NSAID exposure. Oligohydramnios was diagnosed in 41/1092 (3.8%) in the study cohort versus 29/1154 (2.5%) cases in the comparison cohort [RR, 1.5 (95% CI 0.9-2.4)]. Limited to 2nd trimester, oligohydramnios occurred in 8/904 (0.9%) versus 2/1154 (0.2%) pregnancies [RR, 5.1 (95% CI 1.1-24.0)]. At least in four of the 2nd trimester exposed pregnancies NSAID exposure lasted several weeks. Late SAB or stillbirth occurred in 14/1092 (1.3%) versus 17/1154 (1.5%). Postnatal cardiovascular or renal pathology did not differ between the cohorts. CONCLUSIONS: NSAID use in the 2nd trimester limited to a few days does not appear to pose a relevant risk. Use for longer periods in the advanced 2nd trimester, however, may cause oligohydramnios and ductus arteriosus constriction similar to effects observed after 3rd trimester use.

Stability evaluation of morphine, hydromorphone, metamizole and esketamine containing analgesic mixtures applied for patient-controlled analgesia in hospice and palliative care.

In this study, different injection solutions containing opioid and nonopioid compounds used for patient-controlled analgesia in hospice and palliative care were evaluated in terms of analyte stability. Investigated injection solutions contained different combinations of morphine, hydromorphone, metamizole and esketamine. For the practical implementation, samples from infusion pumps were daily drawn over a period of 7 days at 22 and 37°C. Quantitative measurements were performed on a high-performance liquid chromatography system with ultraviolet detection applying a validated analytical method. All compounds apart from morphine showed no evident changes in concentration. However, a significant loss of morphine was observed for injection mixtures containing both morphine and metamizole at 37°C. After 7 days, only 72% of the initially measured morphine concentration was measured in the binary and 77% in the ternary mixture. Furthermore, an additional compound was detected that could represent the morphine-metamizole-adduct, "metamorphine". Based on these results, a significantly reduced morphine concentration must be expected after only 3 days if an injection solution mixture containing both morphine and metamizole is administered to a patient at 37°C. Since the analgesic effects of morphine-metamizole adducts have not yet been thoroughly investigated, further clinical studies are necessary before accurate conclusions can be drawn in this regard.

Pain Management and Analgesics Used in Small Mammals during Post-Operative Period with an Emphasis on Metamizole (Dipyrone) as an Alternative Medication.

Metamizole (dipyrone) is a widely used non-opioid analgesic in both human and animal medicine. Metamizole's safety has been the topic of numerous opposing debates, given the fact that in certain countries metamizole is frequently used as an over-the-counter (OTC) medicine, while in others it is banned due to the risk of agranulocytosis. Further, small mammals such as rabbits, ferrets, rodents, and hedgehogs have become some of the most common pets present in veterinary practice, and each of these species has specific analgesic needs due to their anatomy and physiology. The key to providing appropriate medical care is in finding a substance that has minimal negative effects. In small mammals, analgesia is an important factor and, it happens frequently that, pain in these patients is not well managed. Post-operative pain management is an important topic in the welfare of animals. The objectives of this review, thus, were to provide a concise overview of analgesics that are used in the treatment of postoperative pain in small mammals (e.g., rabbits and rodents) and to highlight the importance of this product, metamizole, in veterinary medicine, as well as the potential of this substance as an alternative analgesic for the treatment of postoperative pain in small mammals.

Simultaneous determination of ergotamine, caffeine and dipyrone in their ternary mixture by applying double divisor and first derivative ratio spectra methods.

Two validated methods namely, double divisor ratio spectra derivative spectroscopy and derivative ratio spectroscopy with zero crossing point were applied to assay a ternary mixture of ergotamine tartrate (EGT), caffeine (CAF) and dipyrone sodium (DIP) without any additional separation steps. The linearity ranges using both methods were (1.0µg/mL-70.0µg/mL), (60.0µg/mL-100.0µg/mL) and (100.0µg/mL-300.0µg/mL) for EGT, CAF and DIP respectively. Double divisor ratio spectroscopy (method A) depends on dividing the different peak responses of EGT on (summation of peaks responses of CAF and DIP each of 10.0µg/mL concentration) at λ max=342nm, 310nm and 315nm for EGT, CAF and DIP respectively. Derivative ratio spectroscopy with zero crossing point (method B) depends on dividing the peak responses of two drugs (EGT and CAF) on (10.0µg/mL of DIP) and dividing the peak response of DIP on peak response of (10.0µg/mL of EGT). The detection limits of the studied drugs applying method A were (3.54, 12.96 and 8.748µg/mL), with quantitation limits of (10.73, 39.28 and 26.51µg/mL) for EGT, CAF and DIP respectively. Regarding method B, the limits of detection and quantitation for EGT were 0.604µg/mL and 1.829µg/mL respectively: with corresponding values of 19.44µg/mL and 58.92µg/mL for CAF and 20.44µg/mL and 61.9µg/mL for DIP. The obtained results were compared to those obtained by published methods and were found to be in accordance.

NAT2 polymorphisms as a cause of metamizole-induced agranulocytosis.

Metamizole is a widely prescribed NSAID with excellent analgesic and antipyretic properties. Although very effective, it is banned in some countries because of the risk for severe agranulocytosis. We here describe three patients with metamizole-associated agranulocytosis. Patient #1 suffered from agranulocytosis and tonsillitis followed by severe sepsis by Streptococcus pneumoniae and Epstein-Barr virus reactivation. Her dizygotic twin sister (patient #2) also suffered from agranulocytosis after a surgical intervention. Patient #3 initially had a tonsillitis and also developed neutropenia after metamizole intake. For all patients, pharmacogenetic diagnostic for the genes CYP2C9, CYP2C19 and NAT2, which are involved in metamizole metabolism and degradation of toxic metabolites, was initiated. Pharmacogenetic analysis revealed NAT2 slow acetylator phenotype in all three patients. Additionally, patient #2 is an intermediate metabolizer for CYP2C19 and patient #3 is a poor metabolizer for CYP2C9. Impairment of these enzymes causes a reduced degradation of toxic metabolites, for example, 4-methylaminoantipyrine (4-MAA) or 4-aminoantipyrine. The metabolite 4-MAA can complex with hemin, which is an early breakdown product during hemolysis. Hemolysis is often observed during invasive infections or after surgical procedures. It is known that the 4-MAA/hemin complex can induce cytotoxicity in the bone marrow and interrupt granulocyte maturation. In conclusion, metamizole-induced agranulocytosis most likely was a consequence of the underlying genetical predisposition, that is, polymorphisms in the genes NAT2, CYP2C9 and CYP2C19. Hemolysis may have increased the toxicity of metamizole metabolites.

Metamizole but not ibuprofen reduces the plasma concentration of sertraline: Implications for the concurrent treatment of pain and depression/anxiety disorders.

AIM: Comorbidity of pain and depression or anxiety is a challenging clinical phenomenon, often requiring the concurrent application of antidepressant and analgesic drugs. Growing evidence suggests that the analgesic metamizole exhibits cytochrome P450 inducing properties. In the present study, we assessed the impact of metamizole and ibuprofen on plasma concentrations of the selective serotonin reuptake inhibitor sertraline. METHODS: Out of a therapeutic drug monitoring (TDM) database, three groups of patients were compared: patients receiving sertraline and metamizole (n = 15), patients receiving sertraline and ibuprofen (n = 19), and a matched control group without one of the analgesics (n = 19). RESULTS: Metamizole was associated with 67% lower median sertraline plasma concentrations compared to the control group (14 vs 42 ng/mL, P < 0.001). In contrast, differences between the ibuprofen group and the control group did not reach statistical significance (31 vs 42 ng/mL, P = 0.128). Moreover, the metamizole group demonstrated lower dose-adjusted drug concentrations than the ibuprofen group (0.10 vs 0.26 (ng/mL)/(mg/day), P = 0.008). Finally, the metamizole group exhibited a higher proportion of patients whose sertraline concentrations were below the therapeutic reference range (40% in the metamizole group, 5% in the ibuprofen group, 0% in the control group, P = 0.005) indicating therapeutically insufficient drug concentrations. CONCLUSION: Our findings support preliminary evidence that metamizole acts as a potent inductor of cytochrome P450 isoenzymes CYP2B6 and CYP3A4. We observed a clinically meaningful pharmacokinetic interaction between metamizole and sertraline, leading to insufficiently low sertraline drug concentrations. Clinicians should therefore consider alternative drug combinations or apply TDM-guided dose adjustment of sertraline.

A possible increased risk of metamizole-associated neutropenia among COVID-19 patients.

Metamizole is commonly used as analgesic and antipyretic drug. The use of metamizole is prohibited in several countries due to its rare side effect of neutropenia and even agranulocytosis. Among the many symptoms of COVID-19, fever and diffuse pain predominant and therefore it can be assumed that metamizole may be widely used in the current epidemic period. So far, there have been no reports on the safety of metamizole in COVID-19 patients. We describe a series of 3 patients who developed severe neutropenia under metamizole treatment, raising a concern of a possible increased risk of this side effect among COVID-19 patients.