Low serum level and chronic toxicity for methotrexate. Case Report.

Introduction: Methotrexate (MTX) is a folic acid antagonist used to treat different immunological or proliferative illnesses because of its anti-proliferative and anti-inflammatory effects. MTX Toxicity is considered a severe problem. Although acute toxicity related to high-dose administration (doses ≥500 mg/m) can be predicted based on the given dose, chronic toxicity still has no specific factors to predict it, so treatment depends on the history and symptoms of toxicity.