Abstract
Methotrexate is an antimetabolite drug with antineoplastic and immunomodulatory properties, useful as an antineoplastic agent in various haematological and solid tumours. MTX toxicity can occur because of accidental ingestion/overdose by the patient or because of prescription error. The toxic effects manifest as severe mucositis or as organ damage (bone marrow depression, renal/hepatic injury). The toxicity usually results from parenteral overdose or repeated chronic drug ingestion. Acute high dose ingestion does not result in MTX toxicity because of saturable absorption kinetics. We present a case of MTX toxicity occurring as a result of prescription error resulting in repeat daily dosing of the drug, and the challenges associated with the management of the same, in a patient with multiple comorbidities. The present case emphasizes on a note of caution on the part of the prescriber and the suggestions regarding the measures which can be taken to avoid MTX toxicity. Keywords: drug overdose; Methotrexate; mucositis; pancytopenia.
Highlights
Methotrexate (MTX) is an antineoplastic and immunomodulatory agent. It competes with folic acid for absorption from the gastrointestinal tract and intracellular metabolism involving the conversion of Dihydrofolate (FH2) to Tetrahydrofolate (FH4) and diminishes the availability of the latter as a reducing agent for DNA and RNA synthesis.[1]
We present a case of MTX toxicity occurring as a result of prescription error, and the challenges associated with its management, in a patient with multiple comorbidities
Methotrexate (MTX) is an antineoplastic drug belonging to antimetabolites class which, by inhibiting cell-mediated immune reactions, exhibits immunomodulatory properties
Summary
Methotrexate (MTX) is an antineoplastic and immunomodulatory agent. It competes with folic acid for absorption from the gastrointestinal tract and intracellular metabolism involving the conversion of Dihydrofolate (FH2) to Tetrahydrofolate (FH4) and diminishes the availability of the latter as a reducing agent for DNA and RNA synthesis.[1]. The patient had a history of pneumonia with sepsis from which he had recently recovered He had multiple comorbidities including Type 2 Diabetes Mellitus for 25 years, Coronary Artery Disease for three years with a history of percutaneous transluminal coronary angioplasty and End Stage Renal Disease for three years. The patient was on injectable insulin for diabetes management and on alternate day maintenance haemodialysis for last 3 months, awaiting renal transplantation. Excision of the middle turbinate and limited functional endoscopic sinus surgery was done till the bleeding margins were achieved and the patient was started on injection liposomal Amphotericin B in a daily dose of 200 mg to a cumulative dose of 4 grams. In view of low WBC counts, the patient was started on prophylactic intravenous injectable antibiotics (Meropenem and Teicoplanin) and intravenous liposomal Amphotericin-B 50 mg on alternate days. The chest tube was subsequently taken out after three days in outpatient setting
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