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MedicineWorld.Org - Cancer-Methotrexate
Your gateway to information on Methotrexate

Methotrexate: resources from Medicineworld.Org

Methotrexate (Amethopterin) 
By Kottapurath Kunjumoideen MD


Methotrexate is a chemotherapy drug that is mainly used in the treatment of the following types of cancers.
  • Breast cancer
  • Head and Neck Cancer
  • Osteogenic sarcoma
  • Acute lymphoblastic leukemia
  • Non-Hodgkin’s disease
  • Meningial leukemia
  • Carcionomatous meningitis
  • Bladder cancer
  • Colorectal cancer
  • Gestational tumors

Description
          When reconstituted, Methotrexate appears as a yellow liquid. This solution is usually administered through the vein however in the treatment of meningeal leukemia and carcinomatous meningitis, this drug is administered directly in to the spinal fluid or brain. Methotrexate may also be It is also available as a 2.5mg or 10 mg tablets. A central line (small catheter into a big vein) or a portocath (similar device which is placed under the skin) is commonly used to administer Methotrexate to the vein.

Side effects
         Side effects associated with Methotrexate may vary from person to person. Some patients may experience significant side effects while others may experience very minimal side effects. It is not possible to predict who is going to have more severe side effects. All the side effects described here will not affect everyone. Most patients will have the common side effects like hair loss, while some other side effects may affect few patients, and may not trouble some others. In this section we will discuss the most common side effects and many less common side effects of methotrexate

Common side effects
Bone marrow suppression and lowering of blood counts

         Use of Methotrexate like many other chemotherapy drugs can cause suppression of the bone marrow and this can result in decreased production of all types of blood cells made from bone marrow. When the white cell production is affected, the condition is called neutropenia. Since white cells are the main types of cells that fight infection, lowering of white cell count can affect your ability to fight infections. It is important to realize that if you get an infection while your white cell count is low (called neutropenia) you may be at significant risk of having serious problems with the infection. Because of this reason if you ever develop a fever while you are on any type of chemotherapy, it is important to make sure that your white blood count is not low. If on the other hand if your white cell count is low with fever (a condition called febrile neutropenia consisting of fever and low white cell count), many times you will have to be admitted to the hospital for intravenous antibiotic treatment. Lowering of red blood cells can result in a condition called anemia. Since red cells are the major carriers of oxygen from lung to different parts of the body, a decrease in red cells (or red colored material in the red cells called hemoglobin) you may experience fatigue, lack of energy and tiredness. If another type of blood component called platelets go down, you may be at risk of bleeding or bruising, since platelets have a major role in prevention of bleeding. The blood counts may start falling in about a week’s time after treatment, however the lowest points in the blood counts are usually seen around 10 to 14 days after treatment. Usually from this point onwards the blood counts usually recover and reaches normal values within 21-28 days.

          The degree of lowering of the blood counts will depend on the type and dose of chemotherapy. Usually your doctor will check the blood counts weekly to monitor your blood counts, however if the blood counts are lower, your doctor may ask you to have blood counts done more often. If the red cells or platelets are very low your doctor may suggest you to have blood or platelet transfusions.

          If any time during your course of chemotherapy you experience fever with temperature going above 38C (100.5F), or you develop any unexplained bruising or bleeding, or you suddenly feel unwell, even with a normal temperature, contact your doctor or the hospital emergency room immediately.

Diarrhea
         Treatment with Methotrexate may lead to diarrhea, however diarrhea is usually mild and usually can be relieved by medications like, Imodium. You should consult your physician if you develop any significant diarrhea while receiving chemotherapy.

Lung toxicity
          Methotrexate treatment may result in lung toxicity. Even though this is rare, you must alert your physician to this possibility if you develop any unexpected shortness of breath.

Mouth ulcers and taste change
         You may develop soreness in the mouth, or may notice small ulcers in the inner parts of your cheeks, back of throat or tongue. Drinking plenty of fluids and having good mouth care with gentle brush may decrease the chance of developing mouth sours.

If this happens, your physician will give you some lotions to apply to the affected areas. You may also have change or loss of taste for food while undergoing chemotherapy. The food may taste different. This problem usually disappears when the treatment is completed and normal taste will come back.

Skin and nail color changes
          Treatment with Methotrexate may result in darkening of your skin. This is due to excess production of pigments. Your skin color may return to normal a few months after the treatment has completed.

Fatigue and tiredness
          Treatment with Methotrexate may result in fatigue and tiredness. Moderate activity and plenty of rest will help you to deal with fatigue and tiredness.

Damage to kidneys
          Methotrexate when in given in large doses can cause damage to the kidney. There is only very low risk for the kidney damage if the standard doses are used. Some times infusion of alkaline fluid may be used with Methotrexate treatment in order to decrease the risk of renal toxicity.

Watering from eyes
          Methotrexate when in given in large doses can cause damage irritation and redness in the eye causing inflammation of the conjunctiva. This may occur with lower doses of Methotrexate. Smoothening eye drops are sometimes prescribed to these patients.

Less common side effects

Nausea and vomiting
         Nausea is the sick feeling that you get when you are going to have vomiting. Methotrexate treatment may cause nausea and vomiting in some patients, however there are very effective medications available, which can be used to prevent or greatly reduce nausea and vomiting. Commonly the nausea and vomiting may occur few hours after the administration of chemotherapy and may last one or more days. Your doctor will give you prescription for nausea medications, and with prudent use of these nauseas medications only few patients will have significant nausea or vomiting. If the nausea or vomiting gets severe your doctor may admit you to the hospital to give you intravenous fluids and anti-nausea medications.

Hair loss
         Hair loss is relatively rare with smaller doses of Methotrexate treatment. However higher doses of Methotrexate can cause significant hair loss. This usually starts 3-4 weeks after the first dose of methotrexate, and may gradually worsen with subsequent doses of methotrexate.

Sensitivity to sunlight
         Your skin may become excessively sensitive to sunlight while you are receiving methotrexate. This effect may also last for several months after completion of the treatment. You should wear a high protection factor sun cream and protective clothing when going out in the sun.

Liver function abnormalities
          Methotrexate may interfere with the normal working of liver causing abnormal liver function tests. This may not cause any harm to you, and your physician will usually monitor the liver function while you are on Methotrexate treatment.

Allergic reactions
         Methotrexate treatment may result in allergic reactions like running nose, irritation of the nose and throat. These usually disappear within 2-3 days.

Skin rash
         Methotrexate treatment may result in allergic reactions in the form of a skin rash. These usually disappear within 3-4 days.

Neurological problems
         High dose methotrexate treatment may result in neurological problems like difficulty in headache, difficulty in speaking, behavioural abnormalities and seizures. If you experinece any ealry neurlogical problems, you must alert your physician to this possibility.

Interaction with other drugs
         Methotrexate may interact with other drugs like coumadin, aspirin, penicillins, anti-inflammatory drugs like ibuprofen etc. If you are taking any of these medications, you should discuss with your physician regarding the possible interaction with methotrexate.



References
  • The Chemotherapy Source Book (4th edition). Ed. Perry. Lippincott, Williams and Wilkins, 2007.
  • Martindale: The Complete Drug Reference (35th edition). Eds. Sweetman et al. Pharmaceutical Press, 2007
  • DeVita, Hellman, and Rosenberg's Cancer: Principles & Practice of Oncology, Eighth Edition
  • Takimoto CH, Calvo E. "Principles of Oncologic Pharmacotherapy": A Multidisciplinary Approach. 11 ed. 2008.



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