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Toxicology Reports Jun 2024Methemoglobinemia is a potentially life-threatening condition caused by the formation of methemoglobin, a form of hemoglobin that cannot bind oxygen. While there are...
Methemoglobinemia is a potentially life-threatening condition caused by the formation of methemoglobin, a form of hemoglobin that cannot bind oxygen. While there are some rare congenital causes of methemoglobinemia, most cases are acquired from the effects of specific drugs or environmental exposures. In this retrospective study, we analyzed a large data set of whole blood samples analyzed for methemoglobin at an academic medical center in Midwestern United States that provides both pediatric and adult services. For a 14 year timeframe (May 2009- June 2023), we performed detailed chart analysis of all patients with a methemoglobin concentration of 3.1 % or higher. For an earlier 13 year timeframe (January 1996-April 2009), we performed chart review for all patients with a methemoglobin concentration of 10.0 % or higher. For the 2009-2023 data, dapsone was the most frequent cause of methemoglobinemia (methemoglobin 3.1 % or higher) in both pediatric (73.3 %, 115 clinical encounters, 105 unique patients) and adult (65.3 %, 195 clinical encounters, 190 unique patients) populations. Inhaled nitric oxide as medical therapy was the next most frequent cause in both pediatric (18.1 %) and adult (13.2 %) populations. Causes associated with two or more unique episodes with methemoglobin concentrations of 10.0 % and higher included the following: dapsone (n = 40 episodes), benzocaine (n = 10), recreational use of amyl or isobutyl nitrite (n = 3), suicide attempt with sodium nitrite (n = 3 with 1 fatality; all 3 cases within last 3 years), food contaminated with nitrates (n = 2), and sepsis (n = 2). A total of 18 patients received treatment with methylene blue including 5 cases associated with benzocaine and all of the cases associated with amyl nitrite, isobutyl nitrite, sodium nitrite, and contaminated food. Only 3 patients with dapsone-associated methemoglobinemia received methylene blue, reflecting primary management by dose reduction or discontinuation of drug. Overall, our data reinforce previous studies showing dapsone, inhaled nitric oxide, and nitrites as common agents causing methemoglobinemia in a patient population seen at a medical center. Our data also are consistent with recent epidemiology trends showing increase in suicide attempts using sodium nitrite.
PubMed: 38544956
DOI: 10.1016/j.toxrep.2024.03.004 -
Pharmaceutics Sep 2023Several studies have demonstrated the feasibility of in situ co-crystallization in different pharmaceutical processes such as spray drying, hot melt extrusion, and...
Several studies have demonstrated the feasibility of in situ co-crystallization in different pharmaceutical processes such as spray drying, hot melt extrusion, and fluidized bed granulation (FBG) to produce co-crystal-in-excipient formulations. However, no previous studies have examined such a one step in situ co-crystallization process for co-crystal formulations where the coformer is a polymer. In the current study, we explored the use of FBG to produce co-crystal granules of dapsone (DAP) and different molecular weight polyethylene glycols (PEGs). Solvent evaporation (SE) was proven to generate DAP-PEGs co-crystals at a particular weight ratio of 55:45 / between DAP and PEG, which was subsequently used in FBG, using microcrystalline cellulose and hydroxypropyl methyl cellulose as filler excipient and binder, respectively. FBG could generate co-crystals with higher purity than SE. Granules containing DAP-PEG 400 co-crystal could be prepared without any additional binder. DAP-PEG co-crystal granules produced by FBG demonstrated superior pharmaceutical properties, including flow properties and tableting properties, compared to DAP and DAP-PEG co-crystals prepared by SE. Overall, in situ co-crystallization via FBG can effectively produce API-polymer co-crystals and enhance the pharmaceutical properties.
PubMed: 37765298
DOI: 10.3390/pharmaceutics15092330 -
Klinische Monatsblatter Fur... Sep 2023Ocular involvement in mucous membrane pemphigoid (MMP) is relatively rare, with a prevalence of 25 cases per million population, equating to approx. 2,100 patients...
BACKGROUND
Ocular involvement in mucous membrane pemphigoid (MMP) is relatively rare, with a prevalence of 25 cases per million population, equating to approx. 2,100 patients throughout Germany. Diagnosis can be difficult - especially in cases of isolated ocular involvement - and treatment can be complex and lengthy. Immunosuppressants or immunomodulatory drugs are often used. Due to the complexity of diagnosis and treatment, MMP patients are usually referred to specialized centers. The aim of this project was to evaluate the current care situation of patients with ocular MMP in Germany.
METHODS
A paper-based survey was designed and sent to all university eye clinics and other specialized centers in Germany in April 2020. The survey asked about the existence of a specialized outpatient service, the total annual number of patients with MMP, the annual number of newly diagnosed patients, any interdisciplinary collaboration for diagnostic or therapeutic purposes, as well as the local and systemic therapy used.
RESULTS
Of a total of 44 clinics, 28 (64%) responded, reporting a total average of 27 ± 42 (0 - 200) patients and 3.6 ± 2.2 (0 - 10) new cases per year. This corresponds to a total of 741 patients. Only nine (32%) of the responding clinics offer specialized MMP clinics. 93% of the centers collaborate with the local dermatology department. 79% perform serological and histological diagnostics in-house. About half of the centers (n = 16) apply a standardized treatment regime. Systemic glucocorticoids (66.7%) are most commonly used, followed by mycophenolate mofetil and dapsone (57.1%), rituximab (33.3%), azathioprine and cyclophosphamide (28.6%), as well as methotrexate (19.0%). The least frequently used treatment is intravenous immunoglobulin (14.3%).
CONCLUSION
This survey of German ophthalmology departments obtained data from about one third of the estimated total cohort of all patients with MMP in Germany. These are presumed to be exclusively patients with at least one ocular involvement. The complex care of these patients is usually provided in collaboration with a dermatologist and with the use of systemic anti-inflammatory medication. Currently, an ophthalmological MMP register is being established to better record the epidemiology and care situation of this rare disease in Germany and to improve it in the long term.
Topics: Humans; Pemphigoid, Bullous; Immunosuppressive Agents; Pemphigoid, Benign Mucous Membrane; Azathioprine; Mucous Membrane
PubMed: 35609814
DOI: 10.1055/a-1720-1819 -
The Journal of Pharmacology and... Sep 2023Glucose 6-phosphate dehydrogenase (G6PD) deficiency is the most common enzymopathy in humans (∼5% of all individuals). G6PD deficiency (G6PDd) is caused by an unstable...
Glucose 6-phosphate dehydrogenase (G6PD) deficiency is the most common enzymopathy in humans (∼5% of all individuals). G6PD deficiency (G6PDd) is caused by an unstable enzyme and manifests most strongly in red blood cells (RBCs) that cannot synthesize new protein. G6PDd RBCs have decreased ability to mitigate oxidative stress due to lower levels of NADPH, as a result of a defective pentose phosphate pathway. Accordingly, oxidative drugs can result in hemolysis and potentially life-threatening anemia in G6PDd patients. Dapsone is a highly useful drug for treating a variety of pathologies but oral dapsone is contraindicated in patients with G6PDd due to oxidative stress-induced anemia. Dapsone must be metabolized to become hemolytic. Dapsone hydroxylamine (DDS-NOH) has been implicated as the major hemolytic dapsone metabolite, but this has never been tested on G6PDd RBCs with in vivo circulation as a metric. Moreover, the metabolic lesion caused by DDS-NOH is unknown. We report that RBCs from a novel humanized mouse expressing the human Mediterranean G6PD-deficient variant have increased sensitivity to DDS-NOH. In addition, we show that DDS-NOH damaged RBCs can either undergo sequestration (with subsequent return to circulation) or permanent removal in a dose-dependent manner, with G6PD-sufficient RBCs mostly being sequestered, and G6PDd RBCs mostly being permanently removed. Finally, we characterize the metabolic lesion caused by DDS-NOH in G6PDd RBCs and report a blockage in terminal glycolysis resulting in a cellular accumulation of pyruvate. These findings confirm DDS-NOH as a hemolytic metabolite and elucidate metabolic effects of DDS-NOH on G6PDd RBCs. SIGNIFICANCE STATEMENT: These findings confirm that dapsone hydroxylamine, an active metabolite of dapsone, causes in vivo clearance of murine red blood cells expressing a human variant of deficient glucose 6-phosphate dehydrogenase (G6PD), an enzymopathy that affects half a billion individuals (G6PD deficiency). Both cellular mechanisms of clearance (sequestration versus destruction) and specific metabolic disturbances caused by dapsone hydroxylamine are elucidated, providing novel mechanistic understanding.
Topics: Animals; Humans; Mice; Dapsone; Erythrocytes; Glucose; Glucosephosphate Dehydrogenase Deficiency; Hemolysis; Phosphates
PubMed: 37348965
DOI: 10.1124/jpet.123.001634 -
Crystal Growth & Design May 2024The dapsone/flavone cocrystal system served as a benchmark for both experimental and virtual screening methods. Expanding beyond this, two additional active...
The dapsone/flavone cocrystal system served as a benchmark for both experimental and virtual screening methods. Expanding beyond this, two additional active pharmaceutical ingredients (APIs), sulfanilamide and sulfaguanidine, structurally related to dapsone were chosen to investigate the impact of substituents on cocrystal formation. The experimental screening involved mechanochemical methods, slurry experiments, hot-melt extrusion, and the contact preparation method. The virtual screening focused on crystal structure prediction (CSP), molecular complementarity, hydrogen-bond propensity, and molecular electrostatic potentials. The CSP studies not only indicated that each of the three APIs should form cocrystals with flavone but also reproduced the known single- and multicomponent phases. Experimentally, dapsone/flavone cocrystals , , , and were reproduced, was identified as a nonstoichiometric hydrate, and a fifth cocrystal (), a -butanol solvate, was discovered. The cocrystal polymorphs and are enantiotripically related, and , exhibiting a different stoichiometric ratio, is enthalpically stabilized over the other cocrystals. For the sulfaguanidine/flavone system, two novel, enantiotripically related cocrystals were identified. The crystal structures of two cocrystals and a flavone polymorph were solved from powder X-ray diffraction data, and the stability of all cocrystals was assessed through differential scanning calorimetry and lattice energy calculations. Despite computational indications, a diverse array of cocrystallization techniques did not result in a sulfanilamide/flavone cocrystal. The driving force behind dapsone's tendency to cocrystallize with flavone can be attributed to the overall strength of flavone interactions in the cocrystals. For sulfaguanidine, the potential to form strong API···API and API···coformer interactions in the cocrystal is a contributing factor. Furthermore, flavone was found to be trimorphic.
PubMed: 38766642
DOI: 10.1021/acs.cgd.4c00293 -
Palliative & Supportive Care Oct 2023Caregivers of patients with primary brain tumor (PBT) describe feeling preoccupied with the inevitability of their loved one's death. However, there are currently no...
OBJECTIVE
Caregivers of patients with primary brain tumor (PBT) describe feeling preoccupied with the inevitability of their loved one's death. However, there are currently no validated instruments to assess death anxiety in caregivers. This study sought to examine (1) the psychometric properties of the Death and Dying Distress Scale (DADDS), adapted for caregivers (DADDS-CG), and (2) the prevalence and correlates of death anxiety in caregivers of patients with PBT.
METHODS
Caregivers ( = 67) of patients with PBT completed the DADDS-CG, Patient Health Questionnaire (PHQ-9), Generalized Anxiety Disorder (GAD-7), Fear of Cancer Recurrence (FCR-7), and God Locus of Health Control (GLHC). Caregivers' sociodemographic information and patients' medical characteristics were also collected. Preliminary examination of the psychometric properties of the DADDS-CG was conducted using exploratory factor analysis, Cronbach's alpha, and correlations. The prevalence and risk factors of death anxiety were assessed using frequencies, pair-wise comparisons, and correlations.
RESULTS
Factor analysis of the DADDS-CG revealed a two-factor structure consistent with the original DADDS. The DADDS-CG demonstrated excellent internal consistency, convergent validity with the PHQ-9, GAD-7, and FCR-7, and discriminant validity with the GLHC. Over two-thirds of caregivers reported moderate-to-severe symptoms of death anxiety. Death anxiety was highest in women and caregivers of patients with high-grade PBT.
SIGNIFICANCE OF RESULTS
The DADDS-CG demonstrates sound psychometric properties in caregivers of patients with PBT, who report high levels of death anxiety. Further research is needed to support the measure's value in clinical care and research - both in this population and other caregivers - in order to address this unmet, psychosocial need.
Topics: Humans; Female; Caregivers; Acedapsone; Anxiety Disorders; Psychometrics; Anxiety; Brain Neoplasms; Reproducibility of Results; Surveys and Questionnaires
PubMed: 35975283
DOI: 10.1017/S1478951522001110 -
Arthritis Care & Research Feb 2024This manuscript assesses the incidence of Pneumocystis jiroveci pneumonia (PJP) among patients receiving contemporary treatment regimens for antineutrophil cytoplasmic...
OBJECTIVE
This manuscript assesses the incidence of Pneumocystis jiroveci pneumonia (PJP) among patients receiving contemporary treatment regimens for antineutrophil cytoplasmic antibody-associated vasculitis (AAV) and adverse events associated with PJP prophylaxis.
METHODS
Incident users of rituximab or cyclophosphamide for AAV were identified in the TriNetX electronic health records database from 2011 to 2022. The incidence rates (IRs) of PJP in the first 6 months of induction therapy with rituximab and/or cyclophosphamide and during postinduction maintenance therapy with rituximab were calculated. Cox proportional hazard models were used to estimate hazard ratios (HRs) and confidence intervals (CIs) for the risk of adverse events commonly associated with PJP prophylaxis.
RESULTS
We identified 1,461 AAV cases who received induction therapy with rituximab (69.7%), cyclophosphamide (18.9%), or both (11.4%). Prophylaxis prescribed within 30 days of induction included trimethoprim-sulfamethoxazole (30.7%), atovaquone (5.4%), dapsone (3.8%), and pentamidine (0.8%). During induction therapy, 10 cases of PJP were identified (IR 15.0 cases per 1,000 patient-years); no deaths occurred. In adjusted analyses, those who received prophylaxis had a higher risk of leukopenia (HR 3.1; 95% CI 1.1-8.6), rash (HR 1.9; 95% CI 1.0-3.6), and nephropathy (HR 2.6; 95% CI 1.3-5.1) than those who did not. During rituximab maintenance therapy (n = 709), five cases of PJP were identified (IR 2.1 cases per 1,000 person-years), one of whom died during the hospitalization associated with a PJP diagnosis.
CONCLUSION
Rates of PJP in patients with AAV were lower than previously observed, and few cases occurred during rituximab maintenance therapy. PJP prophylaxis was associated with adverse events.
Topics: Humans; Rituximab; Pneumocystis carinii; Incidence; Pneumonia, Pneumocystis; Cyclophosphamide; Anti-Neutrophil Cytoplasmic Antibody-Associated Vasculitis
PubMed: 37643919
DOI: 10.1002/acr.25222 -
The World Allergy Organization Journal Jan 2024Trimethoprim-sulfamethoxazole (TMP-SMX) is a broad spectrum antibiotic in use for more than 50 years. It has an important indication as first line agent in the... (Review)
Review
Trimethoprim-sulfamethoxazole (TMP-SMX) is a broad spectrum antibiotic in use for more than 50 years. It has an important indication as first line agent in the prophylaxis of opportunistic infections, particularly pneumonia (PJP), in immunosuppressed patients. For those who have a history of allergy or severe intolerance to TMP-SMX, pentamidine, dapsone or atovaquone may be substituted; however there is evidence that TMP-SMX offers superior coverage for PJP, toxoplasmosis, and nocardiosis. Compared to pentamidine, it has the added benefit of cost-effectiveness and self-administration as opposed to required hospital attendance for administration. Many patients who report a history of allergy or adverse reaction to TMP-SMX (or "sulfur allergy") will be found not to be allergic; and even those who are allergic may be able to be desensitized. The evaluation and, where appropriate, removal of TMP-SMX allergy label enables the use of TMP-SMX for prophylaxis against opportunistic infections. This is a cost-effective intervention to optimize antimicrobial prescribing and reduce the risk of opportunistic infections in immunosuppressed patients.
PubMed: 38235260
DOI: 10.1016/j.waojou.2023.100856 -
Cureus Oct 2023We present the case of a 39-year-old male with a past medical history of orthotopic heart transplantation who presented with chest pain and dyspnea on exertion. He was...
We present the case of a 39-year-old male with a past medical history of orthotopic heart transplantation who presented with chest pain and dyspnea on exertion. He was diagnosed with dapsone-induced methemoglobinemia toward the end of his hospital course, and his condition clinically improved with the discontinuation of the offending agent. This case highlights the importance of medication review and history-taking. Clinicians should be mindful of dapsone-induced methemoglobinemia, especially when encountering patients with dyspnea and a history of dapsone intake.
PubMed: 37942387
DOI: 10.7759/cureus.46690 -
Materials (Basel, Switzerland) Sep 2023Dapsone is an effective antibacterial drug used to treat a variety of conditions. However, the aqueous solubility of this drug is limited, as is its permeability. This...
Dapsone is an effective antibacterial drug used to treat a variety of conditions. However, the aqueous solubility of this drug is limited, as is its permeability. This study expands the available solubility data pool for dapsone by measuring its solubility in several pure organic solvents: N-methyl-2-pyrrolidone (CAS: 872-50-4), dimethyl sulfoxide (CAS: 67-68-5), 4-formylmorpholine (CAS: 4394-85-8), tetraethylene pentamine (CAS: 112-57-2), and diethylene glycol bis(3-aminopropyl) ether (CAS: 4246-51-9). Furthermore, the study proposes the use of intermolecular interactions as molecular descriptors to predict the solubility of dapsone in neat solvents and binary mixtures using machine learning models. An ensemble of regressors was used, including support vector machines, random forests, gradient boosting, and neural networks. Affinities of dapsone to solvent molecules were calculated using COSMO-RS and used as input for model training. Due to the polymorphic nature of dapsone, fusion data are not available, which prohibits the direct use of COSMO-RS for solubility calculations. Therefore, a consonance solvent approach was tested, which allows an indirect estimation of the fusion properties. Unfortunately, the resulting accuracy is unsatisfactory. In contrast, the developed regressors showed high predictive potential. This work documents that intermolecular interactions characterized by solute-solvent contacts can be considered valuable molecular descriptors for solubility modeling and that the wealth of encoded information is sufficient for solubility predictions for new systems, including those for which experimental measurements of thermodynamic properties are unavailable.
PubMed: 37763610
DOI: 10.3390/ma16186336