Immune Checkpoint Inhibitor-Induced Guillain Barre Syndrome: A Single-Institution Case Report and Narrative Review.

Guillain-Barré syndrome (GBS) resulting from the use of immune checkpoint inhibitors (ICIs) is relatively uncommon but has been reported. Herein, we discuss a case of a 67-year-old patient who received neoadjuvant ICI for treatment of non-small cell lung cancer and then presented with lower extremity weakness and areflexia, progressing to respiratory muscle and upper extremity weakness. Given the increasing use of ICI in cancer management, awareness of neurological autoimmune side effects is essential. ICI-mediated GBS can be severe and fatal if not diagnosed promptly. We discuss a case of ICI-induced GBS and review literature on current management approaches.

Intraoperative fluid management is not predictive of AKI in major pancreatic surgery: a retrospective cohort study.

BACKGROUND: Pancreatic surgery is associated with a significant risk for acute kidney injury (AKI) and clinically relevant postoperative pancreatic fistula (CR-POPF). This investigation evaluated the impact of intraoperative volume administration, vasopressor therapy, and blood pressure management on the primary outcome of AKI and the secondary outcome of a CR-POPF after pancreatic surgery. METHODS: This retrospective single-center cohort investigated 200 consecutive pancreatic surgeries (January 2018-December 2021). Patients were categorized for the presence/absence of AKI (Kidney Disease Improving Global Outcomes) and CR-POPF. After univariate analysis, multivariable models were constructed to control for the univariate cofactor differences in the primary and secondary outcomes. RESULTS: AKI was identified in 20 patients (10%) with significant univariate differences in demographics (body mass index and gender), comorbidities, indices of chronic renal insufficiency, and an increased AKI Risk score. Surgical characteristics, intraoperative fluid, vasopressor, and blood pressure management were similar in patients with and without AKI. Patients with AKI had increased blood loss, lower urine output, and packed red blood cell administration. After multivariate analysis, male gender (OR = 7.9, 95% C.I. 1.8-35.1) and the AKI Risk score (OR = 6.3, 95% C.I. 2.4-16.4) were associated with the development of AKI (p < 0.001). Intraoperative and postoperative volume, vasopressor administration, and intraoperative hypotension had no significant impact in the multivariate analysis. CR-POPF occurred in 23 patients (11.9%) with no significant contributing factors in the multivariate analysis. Patients who developed AKI or a CR-POPF had an increase in surgical complications, length of stay, discharge to a skilled nursing facility, and mortality. CONCLUSION: In this analysis, intraoperative volume administration, vasopressor therapy, and a blood pressure < 55 mmHg for more than 10 min were not associated with an increased risk of AKI. After multivariate analysis, male gender and an elevated AKI Risk score were associated with an increased likelihood of AKI.

Integrating Chinese medicine into mainstream cancer therapies: a promising future.

Malignant tumors are complex systemic chronic diseases and one of the major causes of human mortality. Targeted therapy, chemotherapy, immunotherapy, and radiotherapy are examples of mainstream allopathic medicine treatments that effective for intermediate and advanced malignant tumors. The ongoing use of conventional allopathic medicine has resulted in adverse responses and drug resistance, which have hampered its efficacy. As an important component of complementary and alternative medicine, Chinese medicine has been found to have antitumor effects and has played an important role in enhancing the therapeutic sensitivity of mainstream allopathic medicine, reducing the incidence of adverse events and improving immune-related functions. The combined application of adjuvant Chinese medicine and mainstream allopathic medicine has begun to gain acceptance and is gradually used in the field of antitumor therapy. Traditional natural medicines and their active ingredients, as well as Chinese patent medicines, have been proven to have excellent therapeutic efficacy and good safety in the treatment of various malignant tumors. This paper focuses on the mechanism of action and research progress of combining the above drugs with mainstream allopathic medicine to increase therapeutic sensitivity, alleviate drug resistance, reduce adverse reactions, and improve the body's immune function. To encourage the clinical development and use of Chinese herb adjuvant therapy as well as to provide ideas and information for creating safer and more effective anticancer medication combinations, the significant functions of Chinese herb therapies as adjuvant therapies for cancer treatment are described in detail.

Case report: A rare case of anti-PD-1 sintilimab-induced agranulocytosis/severe neutropenia in non-small cell lung cancer and literature review.

Immune checkpoint inhibitors (ICIs) demonstrate unique advantages in the treatment of lung cancer and are widely used in the era of immunotherapy. However, ICIs can cause adverse reactions. Hematological toxicities induced by immunotherapy are relatively rare. Agranulocytosis, a rare hematologic adverse event associated with immune checkpoint inhibitors, has received limited attention in terms of treatment and patient demographics. Herein, we report the case of a 68-year-old male with non-small cell lung cancer(NSCLC) who received two cycles of programmed cell death-1 (PD-1) antibody sintilimab immunotherapy combined with albumin-bound paclitaxel and carboplatin chemotherapy and one cycle of sintilimab monotherapy. He was diagnosed with grade 4 neutropenia and sepsis (with symptoms of fever and chills) after the first two cycles of treatment. Teicoplanin was promptly initiated as antimicrobial therapy. The patient presented with sudden high fever and developed agranulocytosis on the day of the third cycle of treatment initiation, characterized by an absolute neutrophil count of 0.0×109/L. The patient was treated with granulocyte colony-stimulating factor but did not show improvement. He was then treated with corticosteroids, and absolute neutrophil counts gradually returned to normal levels. To the best of our knowledge, this is the first reported case of sintilimab-induced agranulocytosis in a patient with NSCLC. Sintilimab-induced severe neutropenia or agranulocytosis is a rare side effect that should be distinguished from chemotherapy-induced neutropenia and treated promptly with appropriate therapies; otherwise, the condition may worsen.

Comparative analysis of adverse events among intravesical drugs in bladder cancer: a real-world study on FAERS database.

BACKGROUND: Intravesical therapy is a commonly utilized treatment for non-muscle invasive bladder cancer (NMIBC). This study focuses on summarizing the signals of all intravesical drugs and aims to highlight the comprehensive differences in adverse events (AEs) between these drugs. RESEARCH DESIGN AND METHODS: We conducted pharmacovigilance data analysis based on the real-world big data from the Food and Drug Administration Adverse Event Reporting System (FAERS) database. RESULTS: We elucidated all signals compared with the overall FAERS database or other administration routes for Bacillus Calmette-Guerin (BCG), mitomycin, gemcitabine, valrubicin, and epirubicin. Notably, the distribution of reported AEs associated with intravesical therapy exhibited a noticeable inclination toward male patients. Furthermore, all five drugs demonstrated a disproportionate distribution in local AEs, particularly in renal and urinary disorders. Additionally, specific signals and findings were summarized for each individual drug. Finally, we highlighted the AEs that resulted in serious outcomes for each drug. CONCLUSION: We have compiled an overview of the AEs tied to intravesical drugs whilst considering their individual distinctions. These insightful findings serve to enrich our comprehension of the safety profiles and potential risks linked to intravesical therapy.

Case report: a cataract induced by bleomycin in a patient with testicular cancer.

Background: Bleomycin is a glycopeptide antibiotic with outstanding anti-tumor effects. A major adverse effect of bleomycin is lung fibrosis. However, the development of cataracts as a severe adverse effect has not been reported. Case summary: Herein, we describe the first case of cataract induced by bleomycin therapy in a 22-year-old male with testicular cancer. After surgical intervention and following five successive chemotherapy cycles of the BEP regimen, including bleomycin, etoposide and cisplatin, the patient reported a gradual painless loss of vision, with substantial decline in visual ability, especially in the right eye. Following comprehensive eye examinations, a cataract was diagnosed. Eventually, the patient underwent phacoemulsification and received replacement of the intraocular lenses. Conclusion: Bleomycin can cause cataracts, which induces a significant loss of vision. Therefore, clinicians should observe early symptoms and properly adjust treatment to prevent aggravation of symptoms.

Deodorant use and related adverse effects: A cross-sectional survey among Palestinian students.

Background: Deodorants are widely used to mask unpleasant body odors. They are reported to cause some adverse effects depending on the form and ingredients. The purpose of this study was to assess the prevalence of deodorant use and related adverse effects among Palestinian students. Methods: This cross-sectional study was carried out at An-Najah National University from Aug 2018 to Mar 2020. A questionnaire was constructed using a Google survey form. All analyses were done using SPSS 21.0, Fisher test was used for comparative analysis and the P-value < 0.05 was considered as statistically significant. Results: A total of 554 students participated in the study. About 93% of the participants were using deodorants and adverse effects were reported by 25% of the participants. The reported adverse effects were itching (26%), coloration (25%), sneezing (21%), and eye redness (8%). Only 4.1% of the participants visited a physician for counselling regarding various adverse effects. Conclusion: Deodorants were widely used by Palestinian students with reported adverse effects, but these side effects rarely prompted the participants to seek medical advice.

A Superior Squeeze: Superior Vena Cava Syndrome Secondary to Small Cell Lung Cancer.

Superior vena cava (SVC) syndrome is an uncommon yet potentially fatal syndrome occurring after intrinsic or extrinsic compression to the SVC. While there are multiple emerging etiologies for this phenomenon, malignancy remains the most common. It is characterized by several symptoms including facial swelling, extremity swelling, shortness of breath, and headaches. We present the case of a 59-year-old female with a past medical history of cocaine abuse who was admitted for upper extremity swelling and facial edema. Imaging revealed a right suprahilar mass compressing a branch of the right pulmonary artery and SVC, in addition to bilateral segmental and subsegmental pulmonary emboli. She underwent an emergent biopsy and SVC stenting, with immunostaining revealing small cell lung cancer (SCLC). This case highlights a severe presentation of SVC syndrome caused by previously undetected SCLC.

Pulmonary edema after naloxone administration for opioid reversal: a systematic review of case reports and causality assessment using the Naranjo scale.

INTRODUCTION: Pulmonary edema is a rare complication occurring after naloxone administration, but the causal relationship remains insufficiently investigated. We aimed to determine the likelihood of naloxone as the causative agent in published cases of pulmonary edema. METHODS: A literature search was conducted across multiple databases, utilizing database-specific search terms such as "pulmonary edema/chemically induced" and "naloxone/adverse effects." Each case report was evaluated using the Naranjo scale, a standardized causality assessment algorithm. RESULTS: We identified 49 published case reports of pulmonary edema following naloxone administration. The median total dose of naloxone was 0.2 mg for patients presenting following a surgical procedure and 4 mg for out-of-hospital opioid overdoses. Based on the Naranjo scale, the majority of cases were classified as "possible" (n = 38) or "probable" (n = 11) adverse reactions, while no "definite" cases of naloxone-induced pulmonary edema were identified. Many patients were classified as "possible" due to limited patient information or other potential risks, such as fluid administration or airway obstruction. Forty-six of 49 patients survived (94 percent). DISCUSSION: Pulmonary edema may occur after both low and high doses of naloxone; however, low doses were primarily reported in the surgical population. Despite this complication, the majority of patients survived. Furthermore, no case report in our analysis was classified as a "definite" case of naloxone-induced pulmonary edema which limits the establishment of causality. Future studies should explore patient risk factors, including surgical versus outpatient setting and opioid-naïve versus opioid-tolerant for developing pulmonary edema and employ a causality assessment algorithm. CONCLUSIONS: These case reports suggest pulmonary edema can occur following naloxone administration, irrespective of dose. According to the Naranjo scale, there were no definite cases of naloxone-induced pulmonary edema. Overall, we suggest the benefits of naloxone administration outweigh the risks. Naloxone should be administered to treat opioid overdoses while monitoring for the development of pulmonary edema.

Administration of 4% tetrasodium EDTA lock solution and central venous catheter complications in high-risk pediatric patients with intestinal failure: A retrospective cohort study.

BACKGROUND: Selection of central venous catheter (CVC) lock solution impacts catheter mechanical complications and central line-associated bloodstream infections (CLABSIs) in pediatric patients with intestinal failure. Disadvantages of the current clinical standards, heparin and ethanol lock therapy (ELT), led to the discovery of new lock solutions. High-risk pediatric patients with intestinal failure who lost access to ELT during a recent shortage were offered enrollment in a compassionate use trial with 4% tetrasodium EDTA (T-EDTA), a lock solution with antimicrobial, antibiofilm, and antithrombotic properties. METHODS: We performed a descriptive cohort study including 14 high-risk pediatric patients with intestinal failure receiving 4% T-EDTA as a daily catheter lock solution. CVC complications were documented (repairs, occlusions, replacements, and CLABSIs). Complication rates on 4% T-EDTA were compared with baseline rates, during which patients were receiving either heparin or ELT (designated as heparin/ELT). RESULTS: Patients initiated 4% T-EDTA at the time they were enrolled in the compassionate use protocol. Use of 4% T-EDTA resulted in a 50% reduction in CVC complications, compared with baseline rates on heparin/ELT (incidence rate ratio: 0.50; 95% CI, 0.25-1.004; P = 0.051). CONCLUSION: In a compassionate use protocol for high-risk pediatric patients with intestinal failure, the use of 4% T-EDTA reduced composite catheter complications, including those leading to emergency department visits, hospital admissions, additional procedures, and mortality. This outcome suggests 4% T-EDTA has benefits over currently available lock solutions.

Investigating in VigiBase over 6000 cases of pneumonia in clozapine-treated patients in the context of the literature: focus on high lethality and the association with aspiration pneumonia.

BACKGROUND: The literature associates clozapine with pneumonia/aspiration pneumonia. RESEARCH DESIGN AND METHODS: The international pharmacovigilance database (VigiBase™) uses the information component (IC) as statistical signal. VigiBase clozapine reports were analyzed for pneumonia/aspiration pneumonia from introduction to 10 May 2023. RESULTS: There were 6392 cases of all types of pneumonia (5572 cases of pneumonia, 775 of aspiration pneumonia, and 45 combined). The IC was 3.52 for aspiration pneumonia, introduced as a VigiBase label in 2003, and 1.91 for pneumonia. Patients were reclassified as 3628 with no signs of aspiration and 1533 with signs. Signs of aspiration were strongly associated with some co-medications: olanzapine, odds ratio (OR) = 23.8, 95% confidence interval (CI), 14.9-38.0; risperidone OR = 18.6, CI, 11.4-30.4; valproic acid, OR = 5.5, CI, 4.5-6.6; and benzodiazepines OR = 5.5, CI, 4.5-6.6. In 2415 cases with completed data, fatal outcomes made up 45% (signs of aspiration made no difference), but there was wide variability from 0% (females <45 years of age; duration ≤30 days) to 76% (males >64 years of age; duration >1 year). During the first week, pneumonia was associated with 1) very high titration doses, 2) very small doses in Parkinson's disease, and 3) Japan vs other countries. CONCLUSIONS: In clozapine-treated patients: 1) at least 30% of pneumonia cases may be aspiration pneumonia, 2) stopping some co-medications may decrease the risk of aspiration pneumonia, 3) average lethality in pneumonia was 45% but may be around 75% in geriatric patients with long-term treatment, and 4) safer titrations may sometimes require 5-mg tablets.

Safety profile of proprotein convertase subtilisin/kexin type 9 inhibitors alirocumab and evolocumab: an updated meta-analysis and meta-regression.

BACKGROUND: The use of alirocumab and evolocumab is generally safe and well-tolerated. However, concerns remain about their long-term safety, especially with regard to new-onset or worsening diabetes mellitus (DM). We aim to assess the safety profile of alirocumab and evolocumab compared to comparator. METHODS: Studies were retrieved comparing the safety of PCSK9i vs. comparator (placebo or statin with or without ezetimibe). The primary outcome was adverse events leading to death. Secondary outcomes included serious adverse events, new onset diabetes mellitus (DM), worsening of DM, neurocognitive dysfunction, creatine kinase (CK) elevation, elevation of liver enzymes and local injection site reaction. Factors associated with the treatment effect were determined by meta-regression analysis. Subgroup analyses were done to explore potential treatment effect differences based on PCSK9i type and treatment duration. RESULTS: We identified 56 studies with 85,123 adults (29.14% females). PCSK9i was not associated with adverse events that lead to death (OR 0.94, 95% CI 0.84 to 1.04, p = 0.22). Between the two PCSK9i, alirocumab decreased adverse events leading to death (OR 0.79, 95% CI, 0.67 to 0.94, p = 0.008). PCSK9i was associated with less serious events compared to the comparator (OR 0.93, 95% CI 0.89 to 0.98, p < 0.001). This reduction was driven mainly by alirocumab (OR 0.89, 95% CI, 0.85 to 0.93, p < 0.001). Evolocumab worsened DM (OR 2.3, 95% CI 1.26 to 4.2, p = 0.041). Subgroup analysis showed worsening of DM in the first 24 weeks of treatment with odds being highest in the first 12 weeks of treatment (<12 weeks: OR 3.82, 95% CI 1.13 to 12.99, p = 0.03; 12-24 weeks OR 2.12, 95% CI 1.20 to 3.73, p = 0.01. On the other hand, therapy >24 weeks reduced the odds of worsening DM (OR 0.89, 95% CI 0.79 to 0.99, p = 0.04). PCSK9i did not increase cognitive dysfunction, (OR 1.02, 95% CI 0.88 to 1.18, p = 0.76), or cause elevations in liver enzyme (OR 0.91, 95% CI 0.81 to 1.03, p = 0.14), or CK (OR 0.82, 95% CI 0.65 to 1.04, p = 0.10). However, PCSK9i was associated with local injection site reaction (OR 1.54, 95% CI 1.37 to 1.73, p < 0.01). CONCLUSION: Alirocumab decreased adverse events leading to death. Alirocumab and Evolocumab both decreased serious adverse events. PCSK9i did not increase new onset DM however evolocumab worsened DM in the first 24 weeks of treatment. PCSK9i did not increase neurologic dysfunction, and did not elevate liver enzymes and CK, however it was associated with local injection site reaction.

Adverse Effects of Do-It-Yourself Nail Cosmetics: A Literature Review.

Background: As self-applied manicures have gained popularity, it is important for physicians to remain informed about potential associated side effects. Traditional polish remains most popular among nail enthusiasts, but the pursuit of durability and convenience accelerated development of other nail cosmetic products, including gel polish, acrylic nails, and press-on nails. Despite documented adverse effects among beauty professionals and salon customers, individuals practicing at-home nail care routines may face similar, if not more, frequent complications due to misinformation, inadequate training, and social media trends. Summary: This review provides an overview of adverse effects associated with different at-home nail cosmetics. Allergic contact dermatitis is the most prevalent adverse event, primarily attributed to (meth)acrylates found in nail glue, gel polish, and acrylic nails. Other adverse effects include infections, chemical burns, and complications from ultraviolet nail lamps. Key Message: The review highlights the importance of transparent product labeling and appropriate warning labels from manufacturers, as well as physician education and awareness for minimizing risks related to at-home nail cosmetic applications.

Neurovascular Adverse Effects of Sars-Cov-2 Vaccination.

The global deployment of SARS-CoV-2 vaccines has been pivotal in curbing the COVID-19 pandemic, reducing morbidity and mortality associated with the virus. While most of these vaccines have demonstrated high efficacy and overall safety, emerging reports have highlighted potential neurovascular adverse effects, albeit uncommon, associated with these vaccinations. This review aims to assess and summarize the current knowledge on the neurovascular complications arising post-SARS-CoV-2 vaccination. We conducted an extensive literature review, focusing on clinical studies and case reports to identify reported neurovascular events, such as ischemic stroke, cerebral sinus venous thrombosis, intracerebral hemorrhage, pituitary apoplexy and primary CNS angiitis Despite the relative rarity of these events, their impact on affected individuals underscores the importance of ongoing surveillance, early detection, and management strategies. We aim to provide healthcare professionals with the latest evidence on neurovascular adverse effects, facilitating informed decision-making in the context of SARS-CoV-2 vaccination programs. Furthermore, we highlight areas requiring further research to understand the pathophysiology of these adverse events better and to develop targeted prevention and treatment strategies.

Association of Attention Deficit Hyperactivity Disorder with the Use of Oral Propranolol in Infantile Haemangiomas: An Ambispective Comparative Study.

Previous studies have raised concerns about the effects of oral propranolol on the central nervous system in infants, the exact measure and mechanism and the long-term follow-up of which is less well studied. This was an ambispective comparative study of children with infantile haemangioma (IH) followed by a repeat visit 4-10 years after completion of propranolol therapy. Parents were asked about psychologic functioning along with an initial screening examination. All patients were evaluated by a paediatric psychiatrist. After evaluation by the Strength and Difficulties Questionnaire, and subsequently by the paediatric psychiatrist, 2 of 12 patients (16.67%) showed features of attention deficit hyperactivity disorder in comparison to 0 of 40 subjects in the control group (0.0498; α = 0.05). These results indicate an increased risk of neuropsychiatric illnesses such as attention deficit hyperactivity disorder (ADHD) in patients given propranolol for IH, as supporting evidence to previous claims.

Association of clinical, imaging and laboratory parameters with adverse effects of glucocorticoid therapy in patients with giant cell arteritis.

Background: Giant cell arteritis (GCA) is characterized by inflammation of large and medium vessels. First-line therapy for the treatment of GCA are glucocorticoids, which are effective while potential adverse effects should be considered, especially during long-term use. The aim was to investigate the incidence of glucocorticoids' adverse effects and potential predictors for them. Materials and methods: 138 GCA patients were retrospectively evaluated for newly developed glucocorticoid adverse effects in 2020. Potential predictors, defined as initial glucocorticoid pulse therapy, relapse of GCA and concomitant polymyalgia rheumatica as well as parameters of inflammation and endothelial dysfunction, including pulse-wave velocity and intima-media-thickness, were measured in 2012. Results: Potential new glucocorticoid adverse effects per patient was 1 (25th-75th 0-3) of which chronic kidney disease progression (29%), bone fractures (23.2%), cataracts (18.1%), dementia, and arterial hypertension (each at 12.3%) were most commonly recorded. Significant associations were found between occurrence of any relapse and new diabetes mellitus and between initial glucocorticoid pulse therapy and new dementia (all with p < 0.05). In multivariate regression analysis, any relapse was a predictor for developing diabetes mellitus (OR 9.23 [95% CI 1.33-64.05], p = 0.025). However, no correlations were observed between endothelial dysfunction or inflammatory parameters and development of new glucocorticoid adverse effects. Conclusion: GCA relapses may be associated for development of diabetes mellitus potentially by increasing glucocorticoid doses. Parameters of inflammation and endothelial dysfunction are not suited predictors for glucocorticoid adverse effects.

Self-controlled risk interval study of rotavirus vaccine safety: Findings and implications.

BACKGROUND: The self-controlled case series (SCCS) is often used to monitor vaccine safety. The evaluation of intussusception after the rotavirus vaccine is complicated because the baseline rate varies with age. Time-varying baseline risk adjustments with data from unexposed cohorts are utilised. Self-controlled risk interval (SCRI), with a shorter observation period, can also mitigate the problem by studying a control period close to the risk period. OBJECTIVE: An Indian rotavirus vaccine has previously been studied using SCCS. The risk of intussusception in the high-risk windows (21 days after vaccination) was comparable to the background risk. The aim was to re-analyse data of an existing SCCS study using alternate statistical methods to examine vaccine safety. METHODS: We examined the mean age of intussusception in the vaccinated and the unvaccinated. We performed an SCRI analysis of the surveillance data from the SCCS study, limiting the observation period to 180 days. We analysed the time-to-intussusception from the last vaccination. Finally, we performed an SCCS analysis, excluding unvaccinated cases from the analysis. RESULTS: We found that the mean age of intussusception was significantly lower in the vaccinated (205 days) compared to the unvaccinated (223 days) (p-value 0.0026). The Incident Risk Ratio (IRR) on SCRI analysis was 1.62 (95% CI 1.07-2.44). There were significantly more intussusceptions in the first 30 days after vaccination compared to the next 30-day window. (92 vs 63 p-value = 0.009). We found that excluding unvaccinated infants from the SCCS analysis demonstrated significantly increased risk for the risk period 1-21 days after the 3rd dose (IRR 2.47, 95% CI 1.70-3.59). The risks of intussusception were missed in traditional SCCS analysis using unvaccinated infants as controls. CONCLUSION: Traditional risk adjustments using data from unexposed cohorts in SCCS may not be appropriate for investigating the risk of intussusception where vaccination lowers the mean age of intussusception.

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.