>1 micromole per liter toxic plasma methotrexate concentrations

Toxicity of Plasma Methotrexate Concentrations Above 0.1 µmol/L

Plasma methotrexate concentrations greater than 0.1 µmol/L are considered toxic. Toxic levels of methotrexate can cause serious and sometimes life-threatening side effects. The toxic effects of Plasma methotrexate concentrations greater than 0.1 µmol/L can be classified as:

1. Cytotoxicity: Methotrexate is known to cause systemic toxicity by damaging tissues and organs. Symptoms may include abdominal pain, nausea, vomiting, diarrhea, rash, and confusion.
2. Immunosuppression: Methotrexate can suppress the immune system, making it difficult for the body to fight off infections and other illnesses.
3. Neurotoxicity: Methotrexate can cause nerve damage, resulting in numbness, tingling, weakness, confusion, memory loss, and seizures.
4. Cardiotoxicity: Methotrexate can damage the heart, leading to irregular heart beat, chest pain, and heart failure.
5. Hepatotoxicity: Methotrexate can cause liver damage, leading to jaundice, hepatitis, and even death.

Patients should be monitored closely if they are being treated with methotrexate and plasma methotrexate concentrations should be kept at or below 0.1 µmol/L. If toxic effects of higher methotrexate concentrations are experienced, the medication should be stopped and the patient should be monitored to make sure that their condition does not worsen.