Methotrexate is an anti-metabolite medication, meaning that it interferes with the normal cellular metabolism causing cell death. This makes it an ideal chemotherapy agent, and it is used to treat many types of cancers, including but not limited to breast, head, neck, lymph, blood, lung and bone. Because methotrexate is administered systemically, meaning to the whole body, it can also interfere with normal healthy cells functions, leading to unwanted side effects.
Common Side Effects
The most common side effects of methotrexate treatments include nausea, vomiting, diarrhea and loss of appetite. These effects may be temporary, meaning they may subside once your body has adjusted to the medication, especially if the dose of methotrexate is low or medium. Development of sores in the mouth or on the lips is also a common side effect.
Taking methotrexate increases the risk for sunburn, so caution should be taken when going outdoors during the day to avoid this side effect. Wearing protective clothing and sunscreen can help reduce the incidence of this effect.
Methotrexate has the ability to induce radiation recall. This means that if the patient has received radiation treatments in the past, the skin in the area of treatment may become red.
Less Common Side Effects
These less common side effects may occur but do not occur in all patients who take methotrexate. Methotrexate has the ability to decrease the white blood cell count, which increases your risk for other infections. It is important to be aware of any signs of infections including fever, chills, cough or pain during urination.
Methotrexate can also decrease the number of platelets in your blood, which increases the risk of bleeding, even from minor cuts. Signs of a low platelet count include unusual bruising, nosebleeds, bleeding gums and black, tarry stools.
Kidney damage may occur, especially within 24 hours of the start of treatments. This usually occurs when there are a large number of cancer cells present in the body that can be killed by the medication. This condition, known as tumor lysis syndrome, occurs because all the cellular debris from the destroyed cells are filtered through the kidneys, causing the damage.
Rare Side Effects
Liver damage, leading to a poor appetite, weakness, and yellow skin or eyes usually only occurs with prolongs use of the methotrexate. This side effect may be enhanced if alcohol is consumed during treatment.
High doses of methotrexate can cause inflammation of the lungs or even lung collapse of the lung. This lung damage may be accompanied by fever, coughing or shortness of breath.
Methotrexate can trigger a severe skin reaction that begins with a skin rash and progresses to blisters on the skin. If these blisters are accompanied by a fever or body aches, the American Cancer Society suggests discontinuing the medication and seeking immediate medical advice.
Other side effects that rarely occur include hair loss, itchy rash, dizziness and blurred vision. Some patients may experience stroke-like symptoms, including seizure, paralysis, confusion or coma.
