One of the best-known cancer drugs, Methotrexate treats tumors, leukemia, lymphoma, sarcomas and breast cancer, as well as psoriasis and rheumatoid arthritis. Acute side effect reactions occur almost immediately with IV therapy. However, longer-term side effects from oral medications may be slow to manifest until the drug accumulates in the tissues and bloodstream. Dizziness is often the first sign of the most serious--and potentially fatal--central nervous system side effects.
Central Nervous System Side Effects
Within hours of IV infusion of Methotrexate, patients can experience the severe and serious central nervous system (CNS) side effects of arachnoiditis (inflammation of the membrane surrounding the brain), leukoencephalopathy (brain dysfunction of the white matter) and seizures. Dizziness, confusion, syncope (fainting), or sudden and severe headache should be reported to a health care provider immediately. Other side effects that may occur after several weeks of therapy include subacute neurotoxicity (damage to nerve tissue from toxins), demyelination (breakdown of material covering nerves), mild headache, aphasia (difficulty speaking), hemiparesis (paralysis on one side of the body), fever and drowsiness. Methotrexate side effects of the CNS typically require a prescribed medication for effective symptom management.
Hepatic Side Effects
Serious side effects of acute and chronic liver toxicity, as well as liver fibrosis, may occur with Methotrexate therapy. Flu-like symptoms, lethargy, fever, malaise and jaundice of the skin and/or eyes should be reported to a doctor for possible liver damage.
Hematologic Side Effects
Leukopenia and thrombocytopenia (destruction of white blood cells and platelets, respectively) are possible serious side effects of Methotrexate affecting the blood count. As Methotrexate works to destroy cancer cells, it will destroy the body's defense cells as well. Patients are more susceptible to illness and bleeding disorders. Destruction of platelets inhibits the body's ability to clot blood from a small abrasion to a large wound.
Respiratory Side Effects
Pulmonary fibrosis (a thickening of the lung tissue) and pulmonary interstitial infiltrates (fluid in the walls of the lungs) are possible serious side effects affecting the lungs in patients on Methotrexate. A congested cough or a patient's perception that breathing is more difficult should be reported to a physician immediately. Pneumonia and dry, non-productive cough are also possible side effects.
Genitourinary Side Effects
Renal failure (kidney failure) and tubular necrosis (tissue death of kidney) are the most serious genitourinary side effects occurring with Methotrexate therapy. Flank pain, painful urination, scant urine or loss of ability to produce urine should be reported immediately to a health care provider. Menstrual dysfunctions, infertility and spontaneous abortions are other possible side effects.
Gastrointestinal Side Effects
Patients have reported nausea, vomiting, stomach upset, diarrhea and bleeding ulcers while receiving Methotrexate. Patients should discuss symptom management with their doctors before attempting to treat GI distress with over-the-counter medications.
Drug-to-Drug Side Effects
Methotrexate has numerous drug-to-drug side effects. Patients should discuss with their doctor other medications they may be taking before beginning Methotrexate.
Drug-to-Food Side Effects
Food may delay absorption of Methotrexate and reduce its effects on the primary illness. Patients should take Methotrexate on an empty stomach.
References
- "PDR Nurse's Drug Handbook 2010"; Thomson Reuters and Alexander Ivy; 2009
- "Mosby's 2010 Nursing Drug Reference"; Linda Skidmore-Roth; 2009
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