Methotrexate is a prescription medication used for treating cancer, rheumatoid arthritis or psoriasis. Methotrexate binds to an enzyme called dihydrofolate reductase, which prevents the replication of cancer cells. The manner in which methotrexate works in patients who have rheumatoid arthritis is unknown. In psoriasis, the medication prevents skin cells from replicating excessively. Patients should collaborate with a physician to help manage the drug's side effects.
Arachnoiditis
Patients on methotrexate may develop a reaction called arachnoiditis. This reaction manifests as a severe headache, neck rigidity, vomiting and fever. This reaction may occur in over 10 percent of patients on the medication, but may be alleviated by reducing the dose of the drug, explains the “Drug Information Handbook.” Patients must seek medical care if these symptoms develop.
Nausea, Vomiting and Diarrhea
Nausea, vomiting and diarrhea are the most common gastrointestinal side effects of this drug. These effects may occur in up to 10 percent of patients, according to “Pharmacotherapy: A Pathophysiologic Approach.” These effects may be signs of toxicity and may require a reduction in the dose. If these symptoms become severe, patients should receive medical attention immediately.
Elevated Liver Enzymes
Methotrexate may cause elevated levels of liver enzymes. This effect usually resolves within 10 days. Liver function tests, which include the levels of AST and ALT, should be performed periodically. “Pharmacotherapy: A Pathophysiologic Approach” explains that the medication should be discontinued if these test values are greater than twice the upper normal limits. Serum albumin levels should also be monitored regularly because elevated enzyme levels may indicate liver inflammation. Patients should keep all doctor appointments to make sure they are properly monitored.
Effects on White Blood Cells
Methotrexate may cause negative effects on white blood cells, especially when used in the treatment of cancer. More than 10 percent of patients may experience leukopenia, a reduction in the number of white blood cells; a decrease in the activity of the bone marrow is also seen in over 10 percent of individuals, according to “Pharmacotherapy: A Pathophysiologic Approach.” Thrombocytopenia, a low platelet count, may be a sign of toxicity and may require a reduction in the dose. Patients must be monitored regularly to ensure that complications associated with these side effects do not occur.
Stomatitis and Glossitis
Stomatitis is the inflammation of the mucous lining of the structures of the mouth, including the lips, cheeks and gum. This effect may occur in over 10 percent of patients, notes “Pharmacotherapy: A Pathophysiologic Approach.” Glossitis, which is the inflammation of the tongue, may also occur in over 10 percent of patients. Patients experiencing these undesired side effects should speak with a physician. These side effects usually occur within three to seven days after initiating therapy, and resolve within two weeks. The inflammation may cause swelling, which may be dangerous if patients are unable to breathe; patients experiencing shortness of breath should seek emergency medical care.
References
- "Drug Information Handbook"; Charles F. Lacy, Lora L. Armstrong, et al.; 2009
- "Pharmacotherapy: A Pathophysiologic Approach"; Joseph T. Dipiro, Robert L. Talbert, et al.; 2008
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