Methotrexate (MTX)

MTX is a DMARD used to treat inflammatory types of arthritis, such as rheumatoid and psoriatic arthritis.

MTX is the most common medication used to treat inflammatory arthritis. For rheumatoid arthritis, MTX is considered to be the first-line DMARD because of its long-standing benefits.

MTX can be taken orally or given as a subcutaneous (under the skin) or intramuscular (in the muscle) injection.

The most common dose range is 7.5 to 25 mg once a week, given by injection or taken orally in pill form.

The most important thing to remember is that MTX is only taken once a week. Choose a day of the week that is least demanding since some people may feel unwell (tired, stomach upset, loss of appetite) for a day or two after taking MTX.

MTX comes in 2.5 and 10 mg tablets. The 2.5 mg tablets are more commonly used. If you are taking 15 mg or more a week (six or more 2.5 mg tablets), the dose can be split to take half in the morning and half at night (i.e., if you are taking six tablets a week, you can take three with breakfast and three with your evening meal). Dividing doses greater than 15 mg over the day allows for better absorption of your medication. MTX injections are available in a number of strengths. Typically, you will be given 0.3 to 1.0 mL per week.

Methotrexate is a disease modifying anti-rheumatic drug (DMARD).  The mechanism of action for this drug is not well understood but it is though that it helps to suppress the immune system. Scientists believe that it may affect the ability of immune system cells to replicate. By doing this, methotrexate can reduce inflammation and help to reduce pain and swelling in the joints.

Like with many of the DMARDs, you will not feel the effects of MTX right away. Most people start noticing the effects about six to eight weeks after they start to take the medication, however, the full benefit of MTX may not be evident for up to three months. It is important to be patient and continue taking your medication.

To provide symptom relief while you are waiting for MTX to take effect, your prescriber may recommend taking a steroid, such as prednisone or a non-steroidal anti-inflammatory drug (NSAID).

You may not be able to take MTX if you have any blood disorders (i.e., anemia, low platelets), an active infection, severe kidney or liver disorders, problems with your immune system or if you suffer from alcoholism or alcoholic liver disease. If you have any of these conditions, please discuss the situation with your prescriber.
MTX has the potential to harm your liver so your alcohol use must be restricted while taking MTX.

Taking MTX can make it more difficult for your body to fight infections. If you have a fever or think you may have an infection, contact your health-care provider. You may need to stop taking MTX if you are having surgery until you are healed and there is no sign of infection. Please discuss this with your prescriber.

Taking MTX before or during pregnancy can cause birth defects or even a miscarriage. Therefore, if you are pregnant or trying to get pregnant, both partners (man and woman) should refrain from taking this drug. The best time to stop MTX before getting pregnant, for both partners, is not entirely clear. Typically, it is recommended that both partners discontinue MTX for at least three months before pregnancy. If you or your partner are planning to get pregnant, please discuss this with your health-care provider. 

Anyone who has had a previous allergic reaction to MTX should avoid the medication. Any woman who is breastfeeding should also avoid MTX.

MTX interacts with a number of other medications, including some commonly used antibiotics. Please speak with your health-care provider about whether any of the other medications you currently take interact with MTX. If you need an antibiotic while you are taking MTX, be sure to discuss this possible interaction with your prescriber and/or pharmacist.
 

Like all medications, taking MTX carries some risk of side effects, which must be balanced with the potential benefits. In general, the risk of joint damage and permanent disability (resulting from arthritis) is much greater than the risks of side effects from MTX. When monitored properly the vast majority of side effects are rare, generally improve over time and are reversible.

The most common side effects of MTX are nausea, feeling unwell or feeling tired for 24 to 48 hours after taking a dose. This usually improves over time as you get used to taking the medication. In some rare cases, people taking MTX may experience headaches, hair loss, mouth sores or ulcers and/or increased sensitivity to the sun.

MTX may affect your liver and blood counts. This should be closely monitored with routine blood work.

In rare occurrences, MTX may cause a serious lung problem. Please contact your health-care provider if you develop shortness of breath or a new, prolonged cough while taking MTX.

Take MTX as prescribed and contact your health-care provider if you have any concerns while taking the medication.

To reduce some of the side effects, such as nausea and mouth sores, your prescriber may suggest a folic acid supplement to be taken daily or a few times a week while you are taking MTX. Good oral hygiene also helps to prevent the development of mouth sores. Please speak with one of your health-care providers if mouth sores become problematic.

Taking MTX before going to bed can sometimes help you sleep through any unpleasantness, such as nausea.

You may also notice that you are more sensitive to sun exposure while taking MTX, so be sure to use sunscreen regularly.

Restricting your intake of alcohol can also help avoid potential liver problems.

You will need regular blood tests to monitor your liver and blood counts for side effects. When you begin taking MTX your prescriber may request blood work more frequently (every two to four weeks) for a period of time. If you have no issues with the medication during this time, blood tests will be required less frequently (every four to 12 weeks).

Your health-care provider may meet with you regularly to ensure that MTX is adequately controlling your inflammatory arthritis and not causing any adverse effects.

Store oral medication (pills) and pre-filled syringes at room temperature (15 to 25 degrees Celsius) and keep it out of reach of children.

Store multi-dose vials between 15°C and 25°C. After the vials are punctured, the vials should be stored between 2°C and 8°C for a maximum of four weeks (30 days). Protect from light and freezing.