Methotrexate Toxicity Signs

 Methotrexate (Rheumatrex®, Trexall®) is a powerful medication -- so powerful, in fact, that even normal doses used appropriately are quite toxic. Most of the side effects of methotrexate are signs of toxicity to some degree or another. A person can easily develop methotrexate toxicity without overdosing.
 
Possible signs of toxicity include:
 
  • Severe vomiting, diarrhea, or mouth sores -- all of which may contribute to dehydration
  • Signs of low white blood cells, such as frequent infections
  • Signs of low blood platelets or anemia, such as easy bruising or bleeding
  • Signs of liver fibrosis or cirrhosis (two types of liver damage), such as high liver enzymes or abnormal results from a liver biopsy
  • A dry, nonproductive cough, which may be a sign of lung damage.
     
(To learn about other potential signs of toxicity, click Methotrexate Side Effects. This article also offers details on common and less severe reactions to the drug that occurred in clinical trials.)
 
Written by/reviewed by: Kristi Monson, PharmD; Arthur Schoenstadt, MD
Last reviewed by: Kristi Monson, PharmD