Warnings

Methotrexate

Medically Reviewed by Dr. Harshi Dhingra, M.D.

Last Reviewed: Aug 05, 2022

Warnings

Methotrexate Risks, Warnings, and Complications

Methotrexate can cause serious side effects in certain people. Talk to your doctor or pharmacist about other treatment options if you are at high risk of complications from methotrexate use.

MYELOSUPPRESSION AND INCREASED RISK OF INFECTIONS: Methotrexate can affect the bone marrow and result in a low number of blood cells. This can increase the risk of infections and bleeding. Inform your doctor if you have, or have ever had, low blood counts. Call your healthcare provider immediately if you develop fever, sore throat, chills, or other signs of active infection, abnormal bruising or bleeding, extreme fatigue, dyspnea, or pale skin. If you are taking treatment with methotrexate, your blood counts should be closely monitored regularly. Methotrexate can decrease the activity of the immune system and make the patients prone to serious opportunistic infections.
TOXICITY EFFECTS ON THE DIFFERENT BODY PARTS: Methotrexate may result in serious toxicity effects in different organs, i.e. gastrointestinal toxicity and renal toxicity. The drug can put stress on your lungs, liver, gastrointestinal system, kidneys, and nervous system and may lead to bone marrow suppression.
The risk is higher in patients who are alcoholics, on higher doses, taking non-steroidal anti-inflammatory drugs (NSAIDs) such as aspirin, ibuprofen (Advil, Motrin), have impaired renal function, extra fluid in the stomach area or the space around your lungs. You may be more likely to experience severe methotrexate side effects if you have these conditions or take certain drugs. Your doctor will keep a closer eye on you and may need a dose reduction of methotrexate or maybe stop it completely. Call your doctor right away if you experience any of the following symptoms: Liver problems - yellowing of your skin or eyes, pain in the upper right side of your stomach or dark urine; Lung problems - cough, difficulty breathing; Kidney problems - swelling in feet or ankles or decreased or no urine; Stomach problems - nausea, vomiting, diarrhea; Skin problems - skin rash, high fever, sudden blisters; Nerve problems - vision changes, not able to move parts of your body, fatigue, confusion, and drowsiness
HARM OR DEATH OF UNBORN BABY: Methotrexate belongs to category X; thus, it is absolutely contraindicated for use in pregnancy. It can cause harm or death of the fetus. It is important to use a reliable method of birth control for both men and women. Pregnancy needs to be avoided for a minimum of 3 months in the case of men and 6 months in the case of women after the final dose. Talk to your doctor about other options if you or your partner are pregnant or plan to become pregnant.
ALLERGIC REACTIONS: Methotrexate can cause life-threatening allergic reactions. If you develop any of the following symptoms, tell your doctor immediately: fever, rash, blisters, hives, peeling skin, swellings on lips, face, throat, or swallowing difficulties.
TUMOR LYSIS SYNDROME: Methotrexate can cause tumor lysis syndrome in patients with rapidly growing tumors. Inform your doctor immediately if you develop weakness, nausea, diarrhea, muscle cramps, tingling, or decreased urination. Your doctor can provide appropriate prophylactic medications prior to the start of methotrexate tablets in high-risk patients
INFERTILITY: Methotrexate might cause infertility issues in men (low sperm count) and women (menstrual problems), which might be irreversible. Hence, risks should be discussed with your doctor.
RISKS ASSOCIATED WITH LIVE VACCINES: Methotrexate may cause a weakened immune system. Thus, live vaccines such as chicken pox, measles, yellow fever, or mumps and rubella (MMR) vaccines should not be taken by patients. Inform your physician immediately if you experience sudden fever, muscle weakness, and speech or vision changes.
MEDICATION ERRORS: Since methotrexate is often only administered once per week, it is possible to mix up the dosage and inadvertently take more than one dose per week or forget to take it. Advise patients and health providers to take the correct dosage as indicated for patients on a once-weekly dosing schedule because medication errors have resulted in fatalities.
SECONDARY MALIGNANCIES: Using methotrexate may raise your likelihood of developing secondary cancers like lymphoma or acute lymphoblastic leukemia. If you develop lymphoma, it may go away on its own when you stop taking methotrexate, or it may require chemotherapy.
FOLIC ACID SUPPLEMENTATION: Methotrexate reduces folate levels in your body. The recommended dose of folic acid supplements is 5 mg taken orally once a week or 1 mg taken orally once a day, excluding the day you take methotrexate. It is crucial to avoid taking folic acid supplements on the same day as methotrexate.

Precautions Before Starting Methotrexate

Tell your doctor if you have had an allergic reaction to methotrexate or any other medicines in the past.

Give your doctor a complete medical history. Methotrexate may not be right for people with certain medical conditions such as severe liver or kidney disease, any active infection, mouth ulcers, stomach ulcers or duodenal ulcers, alcoholism, cirrhosis, low blood cell counts, a weak immune system, or bone marrow disorder.

Give your doctor and pharmacist a complete list of medications, including prescription drugs, over-the-counter medicines, vitamins, supplements, and herbal products. This can help avoid possible drug interactions.

Tell your doctor if you are pregnant, could be pregnant, are planning a pregnancy, or are breastfeeding.

Methotrexate can increase the sensitivity of your skin to sunlight or ultraviolet light. Wear sunscreen, sunglasses, and protective clothes to avoid unwanted or excessive sun exposure. Sunlamps should not be used while you are using methotrexate. If you take methotrexate and have psoriasis, it could worsen your lesions if exposed to the sun.

Precautions During Use of Methotrexate

Keep all your doctor’s appointments and lab appointments while taking methotrexate. Your physician will tell you to undertake specific lab tests before, during, and after your methotrexate treatment to check your body's response to the medication and to treat side effects before they turn severe.

Tell your doctor if you become pregnant while taking methotrexate.

Be vigilant for signs and symptoms of allergic reactions, toxicities, and immunosuppression such as skin rash, blisters, fever, cough, wheeze, dyspnea, or unusual bleeding. Call your doctor or seek emergency medical help if they occur.

Methotrexate can cause dizziness. Do not drive a motor vehicle or operate machinery until you know how this medicine affects you.

You must not take any vaccinations while taking methotrexate without informing your doctor.

Tell all your doctors you are on methotrexate before any surgery, including dental procedures.

Methotrexate Drug Interactions

Taking methotrexate with certain drugs can affect how the medications work. Possible interactions between drugs can also increase the risk of serious side effects. Your healthcare professional may choose a different medication for you, change the dose or frequency of your medications, and/or closely monitor you for side effects if there are known interactions between methotrexate and your other drugs.

Tell your healthcare provider if you are taking nonsteroidal anti-inflammatory drugs (NSAIDs) such as aspirin, ibuprofen (Advil, Motrin), naproxen (Aleve, Naprosyn), choline magnesium trisalicylate (Tricosal, Trilisate), magnesium salicylate (Doan's), or salsalate. These drugs may increase the risk of experiencing serious side effects of methotrexate.

The risk of developing liver damage can be higher if you are taking any of the following medications: azathioprine (Imuran), acitretin (Soriatane), sulfasalazine (Azulfidine), isotretinoin (Accutane), or tretinoin (Vesanoid). Your doctor may order liver function tests to monitor your liver.

There can also be possible interactions between methotrexate and the following medications:

Antibiotics such as penicillins, chloramphenicol (chloromycetin), and tetracyclines
Sulfonamides such as sulfamethizole (Urobiotic), co-trimoxazole (Bactrim, Septra), sulfadiazine, and sulfisoxazole (Gantrisin)
Other medications for rheumatoid arthritis
Folic acid (available alone or as an ingredient in some multivitamins)
Certain asthma drugs such as theophylline (Theochron, Theolair)
Gout drugs such as probenecid (Benemid)
Seizure drugs such as phenytoin (Dilantin)

The above list may not describe all possible interactions of methotrexate. Give your doctor or pharmacist a complete list of your medications, including prescription drugs, over-the-counter medications, dietary supplements, and herbal remedies. Also, tell your health care professional if you smoke, drink alcohol, or use recreational drugs because some substances can cause serious health complications when used with prescription medications.

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