Methotrexate Injection

Methotrexate injection is an antimetabolite medication. When used for cancer, the high dose works by slowing the growth of cancer cells in the body. At low doses, it suppresses the immune system to slow the progress of autoimmune conditions.

Follow all directions given to you by your doctor and read all documents provided, including the full Prescribing Information, FDA-Approved Product Labeling, Instructions for Use, and Medication Guide before using Methotrexate injection. However, the following is a synopsis of the general guidelines for the use of Methotrexate injection:

• Subcutaneous methotrexate is administered once weekly (not daily). If you miss a dose, contact your pharmacy or healthcare provider.
• Your rheumatologist or healthcare provider will train you on how to properly inject methotrexate. Always follow directions on the product insert.
• Only use each methotrexate syringe once, and dispose of them in a sharps container.
• You may need to have lab tests to check your blood count, kidney, and liver function before and while taking this medication.
• Before getting any vaccine, let your care provider know you are taking methotrexate. Avoid getting any live vaccines while on this medication.
• You may also be prescribed folic acid while on this medication to help reduce side effects.
• If you are using this medication to treat cancer, check your temperature often, and let your doctor know if it goes above 100.4 F.
• Do not drink alcohol while taking this medication.
• This medication can make you more sensitive to the sun, increasing your risk of sunburns and skin cancer. Take care to limit time in the sun during peak hours, and always wear sunscreen. You should also avoid exposure to ultraviolet light from tanning beds and sunlamps.
• If you are female, you may require a pregnancy test before starting this medication.
• If you are male, do not father a child while on this medication. Use effective birth control during treatment and for at least 6 months following. Do not donate sperm during treatment and for at least 6 months following treatment.

The most common side effects of methotrexate include:

• Mouth sores or ulcers.
• Nausea/ vomiting/ diarrhea.
• Stomach upset.
• Dizziness.
• Drowsiness.
• Fever/ chills.
• Hair loss.
• Low white blood cell count or platelet levels.
• Injection site reaction, including blisters, itchiness, pain, redness, or warmth.

Some individuals may experience serious side effects while using Methotrexate injection. These side effects are life-threatening and may require immediate medical attention. If you experience any of the following, contact your healthcare provider or seek emergency medical help:

• A serious infection where your temperature is above 100.4, with or without chills, muscle aches, fast heart rate, or cough.
• Signs of low platelets include blood in the urine or stool, unexplained bruising, cuts that take longer to stop bleeding, or nosebleeds.
• Signs of lung problems such as shortness of breath, fever, or a dry cough.
• Signs of serious liver problems include nausea, vomiting, fatigue, stomach pain, pale-coloured stool, loss of appetite, yellowing of the eyes/ skin, or dark-coloured urine.
• Severe headache, confusion, vision changes, seizure, or difficulty talking.
• Severe skin reactions, including painful blisters, peeling skin, a sore throat, or body aches.
• Signs of an allergic reaction include skin rash (hives), trouble breathing, or swelling of the mouth, lips, or tongue.

These are not all of the possible side effects of Methotrexate injection. You should always seek medical advice from your healthcare provider for any questions or concerns about your medical condition or treatment. Read all patient information, medication guides, or drug information sheets that come with this medication. You can also report adverse effects to the Food and Drug Administration at www.fda.gov/medwatch or 1-800-FDA-1088.

Before starting Methotrexate injection, it is crucial to discuss any existing health conditions with your healthcare provider. You should be sure that your healthcare provider is aware of all your medical conditions, including if you:

• Have kidney disease.
• Are alcoholic or have alcoholic liver disease.
• Ulcerative colitis.
• Are pregnant or planning to become pregnant in the near future.
• Are currently breastfeeding.
• Have any of: bone marrow hypoplasia, leucopenia, thrombocytopenia, or significant anemia.

• Pregnancy.
• Hypersensitivity to methotrexate or any of the inactive ingredients in the formulation.

For rheumatoid arthritis, symptoms start to improve after 3-6 weeks, while it takes about 4-6 weeks for psoriasis. For cancer treatment, methotrexate begins working immediately.

When Methotrexate injection is taken with other prescription drugs, over-the-counter medications, vitamins, and supplements, it may change how they work or increase the frequency or severity of side effects. Make sure that you tell your healthcare professional about anything that you are taking to avoid any negative drug interactions, including:

• Nitrous oxide anesthesia increases the toxicity of methotrexate and should be avoided while you are on this drug.
• Use of non-steroidal anti-inflammatory drugs (NSAIDs), including ibuprofen and naproxen, while on methotrexate is not recommended due to gastrointestinal toxicity.
• Methotrexate should be used with caution with other Disease-Modifying Antirheumatic drugs (DMARDs) such as penicillamine, hydroxychloroquine, or sulfasalazine.
• If you are using methotrexate for psoriasis, the use of amiodarone is contraindicated due to the risk of skin lesions.
• L-asparaginase prevents the action of methotrexate, and should not be taken at the same time.
• Use of methotrexate with diuretics may induce bone marrow suppression.
• Methotrexate in combination with leflunomide may increase the risk of pancytopenia.
• Certain medications may increase the toxicity of methotrexate, including sulfonylureas, aminobenzoic acid, salicylates, phenylbutazone, phenytoin, proton pump inhibitors such as omeprazole or pantoprazole, sulfonamides, penicillins, and tetracycline.
• You should not receive packed red blood cells while on this medication.
• Concurrent use of azathioprine may increase your risk of liver damage.

Methotrexate injection is available as 50mg/mL single-use prefilled syringes, in various doses from 7.5mg to 25mg of methotrexate.

It should be kept at room temperature, protected from light, and away from the reach of children or pets. Discard used syringes in sharps containers.

This is the generic version, but it is also available under the brand names Rasuvo or Otrexup.

Yes, it is available from several manufacturers of generic drugs.

Barring any serious side effects as noted above, Methotrexate injection should not be discontinued unless under the advice of a physician.

No, methotrexate is toxic to a growing fetus and can lead to fetal death and birth defects. Any person of childbearing potential on methotrexate should initiate a trusted form of birth control before starting methotrexate. Males with partners of childbearing potential should also ensure their partners are on an appropriate birth control. You or your partner should continue using birth control for 6 months after the last dose for females or 3 months after the last dose for males. Notify your doctor if you are already pregnant, become pregnant, or if you have any plans to become pregnant.

Methotrexate is contraindicated in nursing patients due to the risk of serious adverse reactions in nursing infants. Talk to your doctor if you are already breastfeeding or if you have any plans to breastfeed. They will know or recommend what is best for you.