Iatrogenically-related, fatal methotrexate intoxication: A series of four cases

Methotrexate-induced Severe Pancytopenia in a Patient with Rheumatoid Arthritis: A Case Report and Review of Literature

Toxicity associated with low doses of methotrexate (MTX) is low, but it may be fatal. Bone marrow suppression and mucositis are among the common side effects of low dose MTX toxicity. Different risk factors have been reported for toxicities associated with low doses of MTX, including accidental use of higher doses, renal dysfunction, hypoalbuminemia, and polypharmacy. In this paper, we present a female patient who had mistakenly used 7.5 mg of MTX daily instead of the same dose of MTX on Thursday and Friday. She was presented with mucositis and diarrhea to the emergency department. Moreover, we searched the databases Scopus and PubMed for available studies and case reports on toxicities associated with MTX dosing errors. The most frequently observed toxicities included gastrointestinal lesions, nausea, vomiting, skin lesions, and bone marrow suppression. Leucovorin, hydration, and urine alkalinization were among the most frequently used treatments. Finally, we summarize the data on the toxicities of low doses of MTX in different diseases.

Toxicological Aspects of Methotrexate Intoxication: Concentrations in Postmortem Biological Samples and Autopsy Findings

The aim of this study was the establishment of a UHPLC-QqQ-MS/MS method to determine methotrexate in postmortem biological samples and quantify the postmortem distribution of methotrexate in a case of fatal intoxication of this drug. A volume of 100 μL or 100 mg of postmortem specimens was precipitated with 400 μL of cold methanol and then analyzed using UHPLC-QqQ-MS/MS. The validation parameters of the method were as follows: limit of quantification: 0.1−1.0 ng/mL or ng/g, coefficient of determination: >0.998 (R2), matrix effect, intra- and inter-day accuracies and precisions: not greater than 13.6%, 14.8% and 17.4%, respectively. The recoveries were: 89.0−113.6%. The postmortem distribution studies revealed methotrexate concentrations as follows: blood—7.2 ng/mL, vitreous humor—0.8 ng/mL, liver—43.7 ng/g, kidney—20.6 ng/g, bone marrow—29.9 ng/g, lumbar vertebra—20.0 ng/g. The highest concentrations of methotrexate after poisoning were found in the tissues with the most rapidly dividing cells. The method described is simple, precise and selective. Methotrexate concentrations can be routinely determined in postmortem specimens. Determination of methotrexate in the postmortem biological material is possible after a few days of intensive treatment.

Methotrexat-Intoxikation nach Therapie einer Psoriasis inversa bei chronischer Niereninsuffizienz

Bei einer pflegebedürftigen Patientin mit chronischer Niereninsuffizienz und Psoriasis vulgaris wurde durch ihre Hautärztin eine Therapie mit Methotrexat verordnet. Die Laborkontrollen sollten über die Hausärztin erfolgen; diese wurden jedoch erst für einen Monat später vereinbart. In der Zwischenzeit hatte der Pflegedienst bereits die erste Methotrexat-Injektion durchgeführt, wonach es zu einer Verschlechterung des Hautzustandes und Schleimhautbeschwerden bei der Patientin kam. Die Hautärztin wies die Patientin daraufhin in eine dermatologische Klinik ein; vorher wurde vom Pflegedienst jedoch eine zweite Methotrexat-Dosis verabreicht. In der Hautklinik wurde aufgrund des Befundes einer erosiven Stomatitis und Vulvitis, einer ausgeprägten Leukopenie und Thrombozytopenie und des Verdachtes auf akutes Nierenversagen eine Methotrexat-Intoxikation diagnostiziert. Die Patientin verstarb wenige Tage später an einem Multiorganversagen.

Methotrexat ist zur Induktionstherapie bei mittelschwerer bis schwerer Psoriasis vulgaris zugelassen. Zu den Gegenanzeigen einer Methotrexat-Therapie zählt nach Leitlinie und Fachinformation eine Niereninsuffizienz; ferner sind Laborkontrollen individualisiert vor der Behandlung, nach einer Woche und nach 6 Wochen und danach alle 6–12 Wochen durchzuführen. Unter arzthaftungsrechtlichen Aspekten dürfte der Einsatz von Methotrexat zur Behandlung einer Psoriasis inversa bei einer betagten Patientin mit Niereninsuffizienz als grober Behandlungsfehler zu bewerten sein; die Nichtdurchführung empfohlener Laborkontrollen ist als Befunderhebungsfehler zu werten. Die Fehleranalyse zeigt allerdings, dass der tragische Verlauf der Methotrexatintoxikation bei besserer Kommunikation zwischen den beteiligten Ärzten und Pflegenden möglicherweise hätte verhindert werden können.

Polymeric Nanoscale Drug Carriers Mediate the Delivery of Methotrexate for Developing Therapeutic Interventions Against Cancer and Rheumatoid Arthritis

Methotrexate (MTX) is widely used as an anticancer and anti-inflammtory drug for treating various types of cancer and autoimmune diseases. The optimal dose of MTX is known to inhibit the dihydrofolatereductase that hinders the replication of purines. The nanobiomedicine has been extensively explored in the past decade to develop myriad functional nanostructures to facilitate the delivery of therapeutic agents for various medical applications. This review is focused on understanding the design and development of MTX-loaded nanoparticles alongside the inclusion of recent findings for the treatment of cancers. In this paper, we have made a coordinated effort to show the potential of novel drug delivery systems by achieving effective and target-specific delivery of methotrexate.

Effect of lutein on methotrexate-induced oxidative lung damage in rats: a biochemical and histopathological assessment

BACKGROUND/AIMS

This study aimed to investigate the effect of lutein on methotrexate (MTX)-induced pulmonary toxicity in rats biochemically and histopathologically.

METHODS

The rats in the MTX + lutein (MTXL, n = 6) group were given 1 mg/kg of lutein orally. A 0.9% NaCl solution was administered orally to the MTX (n = 6) group and the healthy group (HG, n = 6). One hour later, a single 20 mg/kg dose of MTX was injected intraperitoneally in the MTXL and MTX. Lutein or 0.9% NaCl solution was administered once a day for 5 days. At the end of this period, malondialdehyde (MDA), myeloperoxidase (MPO), total glutathione (tGSH), interleukin 1 beta (IL-1β), and tumor necrosis factor alpha (TNF-α) were measured in the lung tissues from the animals euthanized with 50 mg/kg thiopental sodium anesthesia. Subsequently, histopathological examinations were performed.

RESULTS

The levels of MDA, MPO, IL-1β, and TNF-α in the lung tissue of the MTX were significantly higher than those of the MTXL and HG groups (p < 0.0001), and the amount of tGSH was lower. The histopathological findings in the MTX group, in which the oxidants and cytokines were higher, were more severe.

CONCLUSION

Lutein prevented the MTX-induced oxidative lung damage biochemically and histopathologically. This result indicates that lutein may be useful in the treatment of MTX-induced lung damage.

Development of an algorithm to detect methotrexate wrong frequency error using computerized health care data

PURPOSE

We validated an algorithm to detect frequency errors in computerized healthcare data and estimated the incidence of these errors in an integrated healthcare system.

METHODS

We applied Sentinel System analytic tools on the electronic health records of Kaiser Permanente, Northern California, January 1, 2010, through May 30, 2015,to identify rheumatoid arthritis (RA) patients with new use of methotrexate (365-day baseline period). We identified potential methotrexate frequency errors using ICD-9 code 995.20 (adverse drug event), Current Procedural Terminology (CPT) code 96409 for injection of leucovorin and prescription refill patterns. We performed chart review to confirm the frequency errors, assessed performance for detecting frequency errors, and estimated the incidence of chart-confirmed errors.

RESULTS

The study included 24,529 methotrexate dispensings among 3,668 RA patients. Among these, 722 (3%) had one dispensing and 23,807 (97.1%) had ≥2 dispensings during 1-year follow-up period. We flagged 653 (2.7%) with a potential medication error (46 with one dispensing and 607 with ≥2 dispensings). We sampled 94 for chart review, and confirmed three methotrexate errors. All three confirmed frequency errors involved a first methotrexate dispensing followed by injected rescue therapy, leucovorin, (positive predictive value, 60%; 95% confidence interval [CI], 15-95%). No potential errors were found among patients with ≥2 dispensings. We estimated the frequency error incidence among one methotrexate dispensing to be 0.4% (95%CI, 0.1% to 1.2%).

CONCLUSION

Rescue therapy is a specific indicator of methotrexate overdose among first methotrexate dispensings. This method is generalizable to other medications with serious adverse events treated with antidotes.

Adverse consequences of low-dose methotrexate medication errors: data from French poison control and pharmacovigilance centers

OBJECTIVE

The objectives of this study are to carefully describe the context of methotrexate medication errors, to details medical consequences and management approaches, and to determine the rate of fatal outcome.

METHODS

Data on methotrexate medication errors were obtained from the French network of poison control and pharmacovigilance centres, which collected and documented reported drug-induced adverse effects. Cases were included if the intake was more than 2-fold the intended weekly dose or a weekly cumulative dose ≥ 30 mg and a follow-up of at least 4 days after the last dose. Data were analysed for demographics, treatment indication, prescribed dose, drug interactions, clinical complications and medical outcomes.

RESULTS

Seventy four patients were included. The causes of methotrexate errors resulted from an erroneous prescription renewal (23.3%), incomprehensiveness of the weekly schedule by patients or at-home caregivers (56.2%) and administration of a wrong dose by a health care professional (20.5%). Of the 70 patients who took methotrexate daily, the mean daily dose received over the whole duration of the error was 9.6 ± 4.1 mg (range 2.5-22.5) with a mean duration of the error of 11.7 ± 12.2 days (range 2 to 90). Thirteen (18%) patients remained asymptomatic and 61 (82%) developed complications of which 46 (62.2%) were severe. Nine (14.8%) patients died within 11 to 45 days after the first dosing error. Compared to patients with no or mild symptoms, those with severe symptoms were more likely to be older (75.6 ± 10.8 vs. 69.5 ± 12.9 years) and to be exposed to a higher cumulative dose (94.8 ± 46.2 vs. 68.0 ± 45.7 mg).

CONCLUSIONS

This study confirms that dosing errors with methotrexate can be lethal and persisted despite several warnings from drug agencies. Further measures are awaited from the European Medicine Agency.

A decade of Australian methotrexate dosing errors

OBJECTIVE

Accidental daily dosing of methotrexate can result in life-threatening toxicity. We investigated methotrexate dosing errors reported to the National Coronial Information System (NCIS), the Therapeutic Goods Administration Database of Adverse Event Notifications (TGA DAEN) and Australian Poisons Information Centres (PICs).

DESIGN AND SETTING

A retrospective review of coronial cases in the NCIS (2000-2014), and of reports to the TGA DAEN (2004-2014) and Australian PICs (2004-2015). Cases were included if dosing errors were accidental, with evidence of daily dosing on at least 3 consecutive days.

MAIN OUTCOME MEASURES

Events per year, dose, consecutive days of methotrexate administration, reasons for the error, clinical features.

RESULTS

Twenty-two deaths linked with methotrexate were identified in the NCIS, including seven cases in which erroneous daily dosing was documented. Methotrexate medication error was listed in ten cases in the DAEN, including two deaths. Australian PIC databases contained 92 cases, with a worrying increase seen during 2014-2015. Reasons for the errors included patient misunderstanding and incorrect packaging of dosette packs by pharmacists. The recorded clinical effects of daily dosage were consistent with those previously reported for methotrexate toxicity.

CONCLUSION

Dosing errors with methotrexate can be lethal and continue to occur despite a number of safety initiatives in the past decade. Further strategies to reduce these preventable harms need to be implemented and evaluated. Recent suggestions include further changes in packet size, mandatory weekly dosing labelling on packaging, improving education, and including alerts in prescribing and dispensing software.

Comparison of a basic and an advanced pharmacotherapy-related clinical decision support system in a hospital care setting in the Netherlands

OBJECTIVE To compare the clinical relevance of medication alerts in a basic and in an advanced clinical decision support system (CDSS).

DESIGN

A prospective observational study.

MATERIALS AND METHODS

We collected 4023 medication orders in a hospital for independent evaluation in two pharmacotherapy-related decision support systems. Only the more advanced system considered patient characteristics and laboratory test results in its algorithms. Two pharmacists assessed the clinical relevance of the medication alerts produced. The alert was considered relevant if the pharmacist would undertake action (eg, contact the physician or the nurse). The primary analysis concerned the positive predictive value (PPV) for clinically relevant medication alerts in both systems.

RESULTS

The PPV was significantly higher in the advanced system (5.8% vs 17.0%; p<0.05). Significant differences were found in the alert categories: drug-(drug) interaction (9.9% vs 14.8%; p<0.05), drug-age interaction (2.9% vs 73.3%; p<0.05), and dosing guidance (5.6% vs 16.9%; p<0.05). Including laboratory values and other patient characteristics resulted in a significantly higher PPV for the advanced CDSS compared to the basic medication alerts (12.2% vs 23.3%; p<0.05).

CONCLUSION

The advanced CDSS produced a higher proportion of clinically relevant medication alerts, but the number of irrelevant alerts remained high. To improve the PPV of the advanced CDSS, the algorithms should be optimized by identifying additional risk modifiers and more data should be made electronically available to improve the performance of the algorithms. Our study illustrates and corroborates the need for cyclic testing of technical improvements in information technology in circumstances representative of daily clinical practice.

Drugs and pharmaceuticals: management of intoxication and antidotes

The treatment of patients poisoned with drugs and pharmaceuticals can be quite challenging. Diverse exposure circumstances, varied clinical presentations, unique patient-specific factors, and inconsistent diagnostic and therapeutic infrastructure support, coupled with relatively few definitive antidotes, may complicate evaluation and management. The historical approach to poisoned patients (patient arousal, toxin elimination, and toxin identification) has given way to rigorous attention to the fundamental aspects of basic life support--airway management, oxygenation and ventilation, circulatory competence, thermoregulation, and substrate availability. Selected patients may benefit from methods to alter toxin pharmacokinetics to minimize systemic, target organ, or tissue compartment exposure (either by decreasing absorption or increasing elimination). These may include syrup of ipecac, orogastric lavage, activated single- or multi-dose charcoal, whole bowel irrigation, endoscopy and surgery, urinary alkalinization, saline diuresis, or extracorporeal methods (hemodialysis, charcoal hemoperfusion, continuous venovenous hemofiltration, and exchange transfusion). Pharmaceutical adjuncts and antidotes may be useful in toxicant-induced hyperthermias. In the context of analgesic, anti-inflammatory, anticholinergic, anticonvulsant, antihyperglycemic, antimicrobial, antineoplastic, cardiovascular, opioid, or sedative-hypnotic agents overdose, N-acetylcysteine, physostigmine, L-carnitine, dextrose, octreotide, pyridoxine, dexrazoxane, leucovorin, glucarpidase, atropine, calcium, digoxin-specific antibody fragments, glucagon, high-dose insulin euglycemia therapy, lipid emulsion, magnesium, sodium bicarbonate, naloxone, and flumazenil are specifically reviewed. In summary, patients generally benefit from aggressive support of vital functions, careful history and physical examination, specific laboratory analyses, a thoughtful consideration of the risks and benefits of decontamination and enhanced elimination, and the use of specific antidotes where warranted. Data supporting antidotes effectiveness vary considerably. Clinicians are encouraged to utilize consultation with regional poison centers or those with toxicology training to assist with diagnosis, management, and administration of antidotes, particularly in unfamiliar cases.

Early-onset pancytopenia and skin ulcer following low-dose methotrexate therapy

Pancytopenia is a rare but serious adverse effect of low-dose methotrexate (MTX) sodium therapy, and this case report describes a very early-onset of pancytopenia and cutaneous lesions after three days of ingestion. A 64-year-old man was presented to Emergency Department with weakness, fever, poor appetite, nausea, and vomiting after he had had accidentally ingested MTX tablets (2.5 mg) twice a day for the last three days. On initial examination, several painful lesions in his oral mucosa and a cutaneous ulceration on his right foot were also observed. He had severe pancytopenia, poor kidney functions, and abnormal coagulation parameters. The blood level of MTX was found to be within therapeutic range. He was treated with leucovorine, intravenous antibiotics, and appropriate blood transfusions; he was discharged from hospital without any sequela. Pancytopenia associated with low-dose (cumulative dose of 15 mg in 3 days) MTX therapy had not been reported previously. The Naranjo probability scale showed pancytopenia and skin ulcer associated with low-dose MTX therapy as probable adverse reactions. Risk factors for pancytopenia such as renal insufficiency, hypoalbuminemia, low folate levels, concomitant infections, concomitant use of drugs, and folate supplementation were not identified in our patient. Although pancytopenia associated with low-dose MTX therapy is not expected as early as 3 days after initiation of the therapy, physicians should also be aware of this life threatening adverse effect during the very first days of MTX therapy for rheumatoid arthritis patients.

Transgenic rescue of methotrexate-induced teratogenicity in Drosophila melanogaster

The folic acid analog methotrexate (MTX), a competitive inhibitor of dihydrofolate reductase (DHFR), is used to treat a variety of cancers and autoimmune disorders. However, MTX also causes a wide range of toxic effects in healthy cells and is an established teratogen. Efforts to "rescue" the defects caused by MTX by administering a folate analog or by transgenic expression of a DHFR with an altered affinity for MTX have been attempted in a variety of mammals but limited protection was conferred. As a result, our understanding of the effect of MTX at the molecular genetic level remains incomplete and, in addition, continued mammalian sacrifice is not ideal. Due to the similarity of teratogenic effects produced by MTX in Drosophila melanogaster these insects were transformed with DHFR alleles to determine if rescue could be achieved. The resulting "MTX-resistant" flies were subsequently used to investigate changes in gene expression in response to MTX using semiquantitative reverse transcription PCR. The majority (12/14) of key transcripts that were affected in MTX-exposed females including transcripts involved in cell cycle, defense response, and transport were "rescued" in the "MTX-resistant" transgenic flies. These studies illustrate the utility of this invertebrate model for the investigation of molecular effects of MTX-induced teratogenicity, MTX-resistant DHFRs for gene therapy techniques, and teratogenic protection.

The use of low dose methotrexate in rheumatoid arthritis - are we entering a new era of therapeutic drug monitoring and pharmacogenomics?

Methotrexate (MTX) is one of the most commonly used medications in the treatment of rheumatoid arthritis (RA). It has proven efficacy as a sole agent as well as in combination with other disease modifying anti-rheumatic agents (DMARDs) including the newer biological agents. MTX is generally well tolerated although there are a number of potentially serious adverse effects. Of these, haematopoietic suppression, hepatotoxicity and pulmonary toxicity are the more severe and patients are therefore required to have appropriate monitoring while they remain on MTX. In the past, attempts at therapeutic drug monitoring using serum MTX concentrations have been unsuccessful. However, MTX is taken into red blood cells (RBC) where up to four glutamates are added to form MTX polyglutamates (MTXPG(n)). More recently it has been suggested that higher RBC MTXPG(3-5) concentrations may be associated with improved disease control. Genetic variations in enzymes involved in the uptake of MTX into cells and its metabolism are also being examined for their ability to predict drug response and potential for adverse events. While it is unlikely that a single genetic variant will predict efficacy or toxicity there is preliminary evidence that a "pharmacogenetic index" that takes into account the effects of multiple genetic variants maybe useful. Although in their infancy at present, both therapeutic drug monitoring using MTXPG concentrations and pharmacogenomics of MTX may prove useful in the future and are worthy of further investigation.