Patient Articles


What Is Methotrexate?

Methotrexate is sold under the brand names Rheumatrex® or Trexall®. It is widely used to treat people with rheumatoid arthritis or psoriatic arthritis. It is often taken alone at first. Later, other medications (eg, biologics) may be added.

I Do Not Have Cancer. Why Do I Get Methotrexate?

At first, methotrexate was used to treat cancer. But now, it is also used to treat people with rheumatic diseases. Some pharmacists and doctors still call it a chemotherapy treatment. This does not need to concern or frighten you! Methotrexate is used so much by people with rheumatic diseases that it is now calledRheumatrex.

Methotrexate is very different from other medications used in chemotherapy. Most chemotherapy drugs are made to poison cancer cells. But methotrexate does not poison cells. Instead, it hampers the action of an important vitamin called folic acid. Cells use folic acid when they reproduce. Cancer cells and cells in inflamed body parts reproduce very quickly. Therefore, they need a lot of folic acid. Methotrexate keeps these cells from having enough folic acid. This slows down cancer cells and, in rheumatic diseases, cells in inflamed body parts.

The amount of methotrexate used to treat cancer is much higher. In cancer treatment, one or two methotrexate doses may be as large as all the doses you take in two or three years. This makes the possible side effects of methotrexate for cancer very different from the side effects of methotrexate taken for rheumatic diseases.

How Do I Begin Methotrexate?

At the beginning of your treatment, your doctor may prescribe 10 mg to 15 mg of methotrexate per week. (The exact dose depends on your body weight and overall health.) You can take methotrexate as a pill, or it can be injected.

Most people prefer to take pills. The most widely used methotrexate pill, Rheumatrex®, contains a 2.5 mg dose of medication. Trexall® pills contain higher doses. Make sure you know which pill size you are taking!

You can also receive or self-administer methotrexate injections. Injections may have fewer side effects and may work better for some people. So, if you experience serious side effects or do not see good results with methotrexate pills, you may be able to try the injected form. Most people can learn to self-administer the injections.

Will My Dose Be Changed?

Two to four weeks after beginning methotrexate, you need to talk with your doctor. You can either do this by phone or at a follow-up office visit. At that time, you need to tell your doctor whether methotrexate therapy is making you better. You should also talk about any side effects you may have. If needed, your doctor may change your dose at that time. For some people, it may be best to keep taking the same dose. Some side effects may go away over time.

Most people with rheumatoid arthritis or psoriatic arthritis will not need methotrexate doses over 20 mg to 25 mg. Your doctor may order a blood test to measure methotrexate levels in your body. This will help to find the best dose for you.

What Are the Side Effects?

Methotrexate has been used for decades. So, your doctor is very familiar with possible side effects. It is important that you come in for regular checkups and blood tests. Tell your doctor early on about any side effects you may have. Serious side effects take time to develop. When caught early, more serious side effects can be avoided. Here are common side effects to look for:

Digestive Tract Effects

Nausea is the most common digestive side effect. Some people also notice a change in bowel movements. Diarrhea is more common than constipation. These side effects usually lessen or go away, when the dose is changed. Switching to the injectable form of methotrexate may also help.

Liver Abnormalities

Your doctor may ask you to have blood tests to check the health of your liver. These tests may be repeated every four to six weeks. Liver tests are also called liver function tests (LFT). You will see them short as ALT or AST (also called SGPT or SGOT), LDH, bilirubin, and alkaline phosphatase tests.

Minor elevations in these tests are common. Most people can handle them well. But there can be greater problems. Then, you may need a lower dose or the injected form of methotrexate. You may have to stop taking methotrexate. People with psoriatic arthritis or diabetes tend to be at risk for more serious liver changes. To keep liver changes in check, it is important to follow your doctor’s advice about drinking alcohol.

Changes in liver tests may be caused by methotrexate or not. To find the correct reason for liver problems, your doctor may order an abdominal ultrasound or other imaging tests. You may also need to see a doctor dealing with digestive health (gastroenterologist) because they specialize in liver problems also.

Blood Test Abnormalities

Methotrexate can cause a drop in the number of white blood cells, red blood cells, or platelets (cells important for blood clotting). Your doctor may order a complete blood count (CBC) to check that your blood works as it should. The CBC is usually done together with the liver function test.

Allergic Reactions

Some people are allergic to methotrexate. Allergic reaction to methotrexate is not always a rash. Some people get an allergic reaction in their lungs. This usually develops slowly. Early symptoms include a dry cough, especially one day after getting methotrexate. Some people get a low fever and have trouble breathing. If you have these symptoms, call your doctor right away! Call your doctor, even if you think the symptoms are caused by another health problem (eg, a cold).

You may need to get a checkup, a chest X-ray or CAT scan, or pulmonary function tests (breathing tests). Some people may have to see a lung specialist (pulmonologist). You may have to stop taking methotrexate. For serious symptoms, you may need to get a medication called prednisone.

There are many reasons why patients develop breathing problems, and since RA may itself affect the lung, it is important to notify your doctor when you develop breathing problems. That way, your doctor can determine the cause, and therefore the best treatment.

Hair & Mouth Problems

Some people notice that their hair is becoming thinner. Usually, you will not lose hair quickly. You may see some hair on your pillow or the shower floor. Mouth sores may also occur. Taking more folic acid may help to reduce these side effects. But sometimes, the dose of methotrexate must be changed. You may also try the injected form of methotrexate.

Mood Changes

Some people may feel out of sorts the day they take methotrexate or the day after. This is rarely a serious side effect. It often becomes less bothersome or goes away after the first three or four doses. If the problem remains, you may need to change to the injected medication.

Having rheumatoid arthritis or psoriatic arthritis can make you more prone to infections. Taking methotrexate can increase this risk even more. You tend to be more prone to infection, when you take methotrexate together with cortisone (eg, prednisone) or together with biologic medications.

It is important to tell both your rheumatologist and regular doctor, if you think you have an infection! Talk to your doctor, even if you are not sure. Do not wait! It is best to call your doctor when you have the first symptoms. Symptoms of an infection include fever, coughing, chills, severe headache, a painful rash, or a sudden change in your bowel or bladder habits.

When you take methotrexate, it is also important to keep your immunizations up to date. Get the recommended shots for the flu, pneumonia, and hepatitis!

More Information About Methotrexate

You may have more questions about methotrexate. Although the Internet has a lot of information, the information you find may not always be correct. It is much better to ask your pharmacist. If you still have questions, ask your doctor as well.

Always talk to your doctor, if you want to take more or less methotrexate! You need to ask before making any changes to the methotrexate instructions you received. Making changes without your doctor’s okay can be very dangerous!