1. Methotrexate self-injectable solution is available as brand-name drugs. It’s not available in a generic form. Brand names: Rasuvo and Otrexup.
  2. Methotrexate comes in four forms: self-injectable solution, injectable IV solution, oral tablet, and oral solution. For the self-injectable solution, you can either receive it from a healthcare provider, or you or a caregiver can give it to you at home.
  3. Methotrexate self-injectable solution is used to treat psoriasis. It’s also used to treat rheumatoid arthritis, including polyarticular juvenile idiopathic arthritis.

FDA warnings

  • This drug has black box warnings. These are the most serious warnings from the Food and Drug Administration (FDA). Black box warnings alert doctors and patients about drug effects that may be dangerous.
  • Liver problems warning: Methotrexate can cause end-stage liver disease (fibrosis and cirrhosis). Your risk increases the longer you take this drug.
  • Lung problems warning: Methotrexate can cause lung lesions (sores). This effect can occur at any time during your treatment and with any dosage. Stopping treatment may not cause the lesion to go away. Call your doctor right away if you have trouble breathing, shortness of breath, chest pain, or a dry cough while taking this drug.
  • Lymphoma warning: Methotrexate raises your risk of malignant lymphoma (a cancer of the immune system). This risk may or may not go away when you stop taking the drug.
  • Skin reactions warning: Methotrexate can cause skin reactions that could be fatal (cause death). They may or may not go away when you stop taking the drug. If you have certain symptoms while taking this drug, call your doctor or 911 right away. These symptoms include red, swollen, blistered, or peeling skin, rash, fever, red or irritated eyes, or sores in your mouth, throat, nose, or eyes.
  • Infections warning: Methotrexate can make your body less able to fight infection. People taking this drug are at increased risk of serious infections that could be life-threatening. People with an active infection should not start using methotrexate until the infection is treated.
  • Harmful buildup warning: Certain health problems can make your body clear this drug more slowly. This can cause the drug to build up in your body and raise your risk of side effects. If this occurs, your doctor may decrease your dose or stop your treatment. Before starting this drug, tell your doctor if you have kidney problems, ascites (fluid in your abdomen), or pleural effusion (fluid around your lungs).
  • Tumor lysis syndrome warning: If you have a rapidly growing tumor and take methotrexate, you’re at increased risk of tumor lysis syndrome. This condition can be fatal (cause death). Call your doctor right away if you have any symptoms of this syndrome. Symptoms include trouble passing urine, muscle weakness or cramps, upset stomach or no appetite, vomiting, loose stools, or feeling sluggish. They also include passing out, or having a fast heartbeat or a heartbeat that doesn’t feel normal.
  • Warning about treatments that increase side effects: Some medications and treatments can increase the side effects of methotrexate. These include radiation therapy, which raises your risk of bone or muscle damage. These also include use of nonsteroidal anti-inflammatory drugs (NSAIDs). These medications raise your risk of problems with your stomach, bowel, or bone marrow. These problems can be fatal (cause death). Examples of NSAIDs include ibuprofen and naproxen.
  • Pregnancy warning: Methotrexate can seriously harm or end a pregnancy. If you have psoriasis or rheumatoid arthritis and are pregnant, don’t use methotrexate at all. If you get pregnant while taking this drug, call your doctor right away. This drug can also affect sperm. Both men and women should use effective birth control during treatment.
  • Gastrointestinal tract warning: Methotrexate can cause severe diarrhea. It can also cause ulcerative stomatitis, an infectious disease of the mouth resulting in swollen, spongy gums, sores, and loose teeth. If these effects occur, your doctor may interrupt your treatment with this drug.

Other warnings

  • Incorrect dosage warning: This medication should be injected once weekly. Taking this medication every day can lead to death.
  • Dizziness and tiredness warning: This medication can make you feel very dizzy or tired. Don’t drive or use heavy machinery until you know you can function normally.
  • Anesthesia warning: This drug can interact with anesthesia that contains a drug called nitrous oxide. If you’ll be having a medical procedure that requires anesthesia, be sure to tell your doctor and surgeon that you use methotrexate.

Methotrexate is a prescription medication. It comes in four forms: self-injectable solution, injectable IV solution, oral tablet, and oral solution.

For the self-injectable solution, you can receive the injection from a healthcare provider. Or, if your healthcare provider feels you’re capable, they can train you or a caregiver to administer the drug at home.

Methotrexate self-injectable solution is available as the brand-name drugs Rasuvo and Otrexup. It’s not available in a generic version.

Methotrexate self-injectable solution may be used as part of a combination therapy. That means you may need to take it with other drugs.

Why it's used

Methotrexate self-injectable solution is used to treat psoriasis. It’s also used to treat rheumatoid arthritis, including polyarticular juvenile idiopathic arthritis (JIA).

How it works

Methotrexate belongs to a class of drugs called antimetabolites, or folic acid antagonists. A class of drugs is a group of medications that work in a similar way. These drugs are often used to treat similar conditions.

Methotrexate works differently for each condition it treats. It isn’t exactly known how this drug works to treat rheumatoid arthritis (RA). RA is a disease of the immune system. It’s believed that methotrexate weakens your immune system, which may help reduce pain, swelling, and stiffness from RA.

For psoriasis, methotrexate slows down how fast your body produces the top layer of your skin. This helps to treat the symptoms of psoriasis, which include dry, itchy patches of skin.

Methotrexate injectable solution can cause drowsiness. Don’t drive or use heavy machinery until you know you can function normally.

Methotrexate can also cause other side effects.

More common side effects

The more common side effects of methotrexate can include:

  • nausea or vomiting
  • stomach pain or upset
  • diarrhea
  • hair loss
  • tiredness
  • dizziness
  • chills
  • headache
  • sores in your lungs
  • mouth sores
  • painful skin sores
  • bronchitis
  • fever
  • bruising more easily
  • increased risk of infection
  • sun sensitivity
  • rash
  • stuffy or runny nose and sore throat
  • abnormal results on liver function tests (may indicate liver damage)
  • low blood cell levels

If these effects are mild, they may go away within a few days or a couple of weeks. If they’re more severe or don’t go away, talk to your doctor or pharmacist.

Serious side effects

Call your doctor right away if you have serious side effects. Call 911 if your symptoms feel life-threatening or if you think you’re having a medical emergency. Serious side effects and their symptoms can include the following:

  • Unusual bleeding. Symptoms can include:
    • vomit that contains blood or looks like coffee grounds
    • coughing up blood
    • blood in your stool, or black, tarry stool
    • bleeding from your gums
    • unusual vaginal bleeding
    • increased bruising
  • Liver problems. Symptoms can include:
    • dark-colored urine
    • vomiting
    • pain in your abdomen
    • yellowing of your skin or the whites of your eyes
    • tiredness
    • lack of appetite
    • light-colored stools
  • Kidney problems. Symptoms can include:
    • not being able to pass urine
    • decreased urination
    • blood in your urine
    • significant or sudden weight gain
  • Pancreas problems. Symptoms can include:
    • severe pain in your abdomen
    • severe back pain
    • upset stomach
    • vomiting
  • Lung lesions (sores). Symptoms can include:
    • a dry cough that doesn’t produce phlegm
    • fever
    • shortness of breath
  • Lymphoma (cancer). Symptoms can include:
    • tiredness
    • fever
    • chills
    • weight loss
    • loss of appetite
  • Skin reactions. Symptoms can include:
    • rash
    • redness
    • swelling
    • blisters
    • peeling skin
  • Infections. Symptoms can include:
    • fever
    • chills
    • sore throat
    • cough
    • ear or sinus pain
    • saliva or mucus that increases in amount or is a different color than normal
    • pain while urinating
    • mouth sores
    • wounds that won’t heal
    • anal itching
  • Bone damage and pain
  • Bone marrow damage. Symptoms can include:
    • low white blood cell levels, which can cause infection
    • low red blood cell levels, which can cause anemia (with symptoms of tiredness, pale skin, shortness of breath, or a fast heart rate)
    • low platelet levels, which can lead to bleeding

Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs affect each person differently, we cannot guarantee that this information includes all possible side effects. This information is not a substitute for medical advice. Always discuss possible side effects with a healthcare provider who knows your medical history.

Keep in mind

  • Dehydration (low fluid levels in your body) can worsen the side effects of this drug. Be sure to drink enough fluids before taking this drug.
  • Methotrexate can cause mouth sores. Taking a folic acid supplement may decrease this side effect. It may also help decrease certain kidney or liver side effects from methotrexate. Your doctor can tell you more.

Methotrexate self-injectable solution can interact with other medications, vitamins, or herbs you may be taking. An interaction is when a substance changes the way a drug works. This can be harmful or prevent the drug from working well.

To help avoid interactions, your doctor should manage all of your medications carefully. Be sure to tell your doctor about all medications, vitamins, or herbs you’re taking. To find out how this drug might interact with something else you’re taking, talk to your doctor or pharmacist.

Examples of drugs that can cause interactions with methotrexate are listed below.

Drugs you should not use with methotrexate

Do not take these drugs with methotrexate. When used with methotrexate, these drugs can cause dangerous effects in your body. Examples of these drugs include:

  • Live vaccines. When used with methotrexate, live vaccines raise your risk of infection. The vaccine may also not work as well. (Live vaccines, such as FluMist, are vaccines that contain small amounts of live, but weakened, viruses.)

Interactions that increase your risk of side effects

Increased side effects from other drugs: Taking methotrexate with certain medications raises your risk of side effects from those drugs. Examples of these drugs include:

  • Certain asthma drugs such as theophylline. Increased side effects of theophylline can include rapid heartbeat.

Increased side effects from methotrexate: Taking methotrexate with certain medications raises your risk of side effects from methotrexate. This is because the amount of methotrexate in your body may be increased. Examples of these drugs include:

  • Nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen, naproxen, aspirin, diclofenac, etodolac, or ketoprofen. Increased side effects can include bleeding, problems with your bone marrow, or serious problems with your digestive tract. These problems can be fatal (cause death).
  • Seizure drugs such as phenytoin. Increased side effects can include upset stomach, hair loss, tiredness, weakness, and dizziness.
  • Gout drugs such as probenecid. Increased side effects can include upset stomach, hair loss, tiredness, weakness, and dizziness.
  • Antibiotics such as penicillin drugs, which include amoxicillin, ampicillin, cloxacillin, and nafcillin. Increased side effects can include upset stomach, hair loss, tiredness, weakness, and dizziness.
  • Proton pump inhibitors such as omeprazole, pantoprazole, or esomeprazole. Increased side effects can include upset stomach, hair loss, tiredness, weakness, and dizziness.
  • Skin drugs such as retinoids. Increased side effects can include liver problems.
  • Post-transplant drugs such as azathioprine. Increased side effects can include liver problems.
  • Anti-inflammatory drugs such as sulfasalazine. Increased side effects can include liver problems.
  • Antibiotics such as trimethoprim/sulfamethoxazole. Increased side effects can include bone marrow damage.
  • Nitrous oxide, an anesthesia drug. Increased side effects can include mouth sores, nerve damage, and a reduction in blood cell counts that may increase your risk of infection.

Interactions that can make your drugs less effective

When methotrexate is less effective: When methotrexate is used with certain drugs, it may not work as well to treat your condition. This is because the amount of methotrexate in your body may be decreased. Examples of these drugs include:

  • Antibiotics such as tetracycline, chloramphenicol, or those that work on bacteria in your bowel (such as vancomycin). Your doctor may adjust your dosage of methotrexate.

Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs interact differently in each person, we can not guarantee that this information includes all possible interactions. This information is not a substitute for medical advice. Always speak with your healthcare provider about possible interactions with all prescription drugs, vitamins, herbs and supplements, and over-the-counter drugs that you are taking.

This drug comes with several warnings.

Allergy warning

Methotrexate can cause a severe allergic reaction. Symptoms may include:

  • trouble breathing
  • swelling of your throat or tongue
  • hives

If you develop these symptoms, call 911 or go to the nearest emergency room.

Don’t take this drug again if you’ve ever had an allergic reaction to it. Taking it again could be fatal (cause death).

Alcohol interaction warning

Avoid drinking alcohol when you’re taking methotrexate. Alcohol can increase the side effects of methotrexate on your liver. This can cause liver damage or worsen liver problems that you already have.

Warnings for people with certain health conditions

For people with liver disease: Don’t use methotrexate if you have a history of liver problems, including alcohol-related liver problems. This drug can make your liver function worse. If your doctor prescribes this drug, they will decide your dosage partly based on your liver health. Depending on your level of liver disease, your doctor may decide that you should not take methotrexate.

For people with weakened immune systems: Don’t use methotrexate if you have a weakened immune system or an active infection. This drug can make these problems worse.

For people with low blood cell counts: These include low counts of white blood cells, red blood cells, or platelets. Methotrexate can make your low blood cell levels worse.

For people with kidney disease: If you have kidney problems or a history of kidney disease, you may not be able to clear this drug from your body well. This may increase the levels of methotrexate in your body and cause more side effects. This drug can also cause problems with your kidney function or even cause your kidneys to fail, leading to the need for dialysis. If your doctor prescribes this drug, they will decide your dosage partly based on your kidney health. If your kidney damage is severe, your doctor may decide that you should not take methotrexate.

For people with ulcers or ulcerative colitis: Do not use methotrexate. This medication can make these conditions worse by increasing the risk of ulcers (sores) in your gastrointestinal tract.

For people with rapidly growing tumors: Methotrexate can cause tumor lysis syndrome. This condition can occur after the treatment of certain cancers. It can cause problems with your electrolyte levels, which can lead to severe kidney failure or even death.

For people with pleural effusion or ascites: Pleural effusion is fluid around the lungs. Ascites is fluid in your abdomen. Methotrexate may stay in your body for a longer time if you have these medical problems. This could lead to more side effects.

For people with worsened psoriasis due to light exposure: If you’ve had psoriasis that gets worse from ultraviolet (UV) radiation or exposure to sunlight, methotrexate may cause this reaction to happen again.

Warnings for other groups

For pregnant women: Methotrexate can cause serious harm to a pregnancy. It can also cause fertility problems (make it harder to get pregnant). People with RA or psoriasis should not use this drug during pregnancy.

If you’re a woman of childbearing age, your doctor will likely give you a pregnancy test to make sure you’re not pregnant before starting this drug. You should use effective birth control during your treatment and for at least one menstrual cycle after stopping treatment with this drug. Call your doctor right away if you:

  • miss a period
  • think your birth control didn’t work
  • become pregnant while taking this drug

If you’re a man, you should use effective birth control during your treatment and for at least 3 months after your treatment ends.

For women who are breastfeeding: Methotrexate passes through breast milk and can cause side effects in a child who is breastfed. Do not breastfeed while taking methotrexate. Talk with your doctor about the best way to feed your child.

For seniors: You’re more likely to have problems with their liver, kidneys, or bone marrow while taking methotrexate. You’re also more likely to have low folic acid levels. Your doctor should monitor you for these and other side effects.

For children: For psoriasis: This medication has not been studied in children with psoriasis. It should not be used to treat this condition in children younger than 18 years.

For polyarticular juvenile idiopathic arthritis: This medication has been studied in children ages 2–16 years with this condition.

All possible dosages and drug forms may not be included here. Your dosage, drug form, and how often you take the drug will depend on:

  • your age
  • the condition being treated
  • how severe your condition is
  • other medical conditions you have
  • how you react to the first dose

Drug forms and strengths

Brand: Otrexup

  • Form: subcutaneous injection (auto-injector)
  • Strengths: 10 mg/0.4 mL, 12.5 mg/0.4 mL, 15 mg/0.4 mL, 17.5 mg/0.4 mL, 20 mg/0.4 mL, 22.5 mg/0.4 mL, 25 mg/0.4 mL

Brand: Rasuvo

  • Form: subcutaneous injection (auto-injector)
  • Strengths: 7.5 mg/0.15 mL, 10 mg/0.2 mL, 12.5 mg/0.25 mL, 15 mg/0.3 mL, 17.5 mg/0.35 mL, 20 mg/0.4 mL, 22.5 mg/0.45 mL, 25 mg/0.5 mL, 30 mg/0.6 mL

Dosage for psoriasis

Adult dosage (ages 18–64 years)

  • Typical starting dosage: 10–25 mg once per week.
  • Maximum dosage: 30 mg once per week.

Child dosage (ages 0–17 years)

This drug has not been established as safe and effective for the treatment of psoriasis in this age group.

Senior dosage (ages 65 years and older)

Your kidneys may not work as well as they used to. This can cause your body to process drugs more slowly. As a result, a higher amount of a drug may stay in your body for a longer time. This raises your risk of side effects.

Your doctor may start you on a lower dosage or a different dosing schedule. This can help keep levels of this drug from building up too much in your body.

Dosage for rheumatoid arthritis

Adult dosage (ages 17–64 years)

  • Typical starting dosage: 7.5 mg once per week.

Child dosage (ages 0–17 years)

This drug is not approved to treat RA in children.

Senior dosage (ages 65 years and older)

The kidneys of older adults may not work as well as they used to. This can cause your body to process drugs more slowly. As a result, more of a drug may stay in your body for a longer time. This raises your risk of side effects.

Your doctor may start you on a lowered dose or a different dosing schedule. This can help keep levels of this drug from building up too much in your body.

Dosage for polyarticular juvenile idiopathic arthritis (JIA)

Child dosage (ages 2–16 years)

  • Typical starting dosage: 10 mg per meter squared (m2) of body surface area, once per week.

Child dosage (ages 0–1 year)

This drug has not been proven to be safe and effective for children younger than 2 years.

Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs affect each person differently, we cannot guarantee that this list includes all possible dosages. This information is not a substitute for medical advice. Always speak with your doctor or pharmacist about dosages that are right for you.

Methotrexate is used for short-term or long-term treatment. Your length of treatment depends on the condition being treated. This drug comes with serious risks if you don’t take it as prescribed.

If you stop taking the drug suddenly or don’t take it at all: You may have problems that depend on the condition being treated.

  • For RA or JIA: Your symptoms, such as inflammation and pain, may not go away or may get worse.
  • For psoriasis: Your symptoms may not improve. These symptoms can include itchiness, pain, red patches of skin, or silver or white layers of scaly skin.

If you miss doses or don’t take the drug on schedule: Your medication may not work as well or may stop working completely. For this drug to work well, a certain amount needs to be in your body at all times.

If you take too much: You could have dangerous levels of the drug in your body. An overdose can cause problems that include:

  • low white blood cell levels and infections, with symptoms such as fever, chills, cough, body aches, pain when urinating, or white patches in your throat
  • low red blood cell levels and anemia, with symptoms such as extreme tiredness, pale skin, a fast heart rate, or shortness of breath
  • low platelet levels and unusual bleeding, such as bleeding that won’t stop, coughing up blood, vomiting blood, or blood in your urine or stools
  • mouth sores
  • severe stomach side effects, such as pain, nausea, or vomiting

If you think you’ve taken too much of this drug, call your doctor or local poison control center. If your symptoms are severe, call 911 or go to the nearest emergency room right away.

What to do if you miss a dose: Take your dose as soon as you remember. If you remember just a few hours before your next scheduled dose, take only one dose. Never try to catch up by taking two doses at once. This could result in dangerous side effects.

How to tell if the drug is working: You may have signs of improvement. They depend on the condition being treated.

  • For RA or JIA: You should have less pain and swelling. People often see improvement 3–6 weeks after starting the medication.
  • For psoriasis: You should have less dry, scaly skin.

Keep these considerations in mind if your doctor prescribes methotrexate for you.

General

  • Take this drug at the time(s) recommended by your doctor.

Storage

  • Store methotrexate injectable solution at room temperature, between 59°F and 86°F (15°C and 30°C).
  • Keep this medication away from light.
  • Don’t store this medication in moist or damp areas, such as bathrooms.

Refills

A prescription for this medication is refillable. You should not need a new prescription for this medication to be refilled. Your doctor will write the number of refills authorized on your prescription.

Travel

When traveling with your medication:

  • Always carry your medication with you. When flying, never put it into a checked bag. Keep it in your carry-on bag.
  • Don’t worry about airport X-ray machines. They can’t harm your medication.
  • You may need to show airport staff the pharmacy label for your medication. Always carry the original prescription-labeled container with you.
  • Don’t put this medication in your car’s glove compartment or leave it in the car. Be sure to avoid doing this when the weather is very hot or very cold.

Self-management

If you will be self-injecting methotrexate, your healthcare provider will show you or your caregiver how to do it. You should not inject the medication until you have been trained on the correct way to do it. Be sure you are comfortable with the process, and don’t forget to ask your healthcare provider any questions you have.

For each injection, you’ll need:

  • gauze
  • cotton balls
  • alcohol wipes
  • a bandage
  • a trainer device (provided by your doctor)

Clinical monitoring

Your doctor may do tests during your treatment to make sure the medication isn’t harming your body. These tests may include blood tests and x-rays, and can check the following:

  • blood cell levels
  • platelet levels
  • liver function
  • blood albumin levels
  • kidney function
  • lung function
  • level of methotrexate in your body
  • the amount of calcium, phosphate, potassium, and uric acid in your blood (can detect tumor lysis syndrome)

Sun sensitivity

Methotrexate can make your skin more sensitive to the sun. This increases your risk of sunburn. Avoid the sun if you can. If you can’t, be sure to wear protective clothing and apply sunscreen.

Availability

Not every pharmacy stocks this drug. When filling your prescription, be sure to call ahead to make sure your pharmacy carries it.

Hidden costs

  • You may need to have blood tests done during your treatment with methotrexate. The cost of these tests will depend on your insurance coverage.
  • You’ll need to purchase the following materials to self-inject this medication:
    • gauze
    • cotton balls
    • alcohol wipes
    • bandages

Prior authorization

Many insurance companies require a prior authorization for this drug. This means your doctor will need to get approval from your insurance company before your insurance company will pay for the prescription.

There are other drugs available to treat your condition. Some may be better suited for you than others. Talk to your doctor about other drug options that may work for you.

Disclaimer: Healthline has made every effort to make certain that all information is factually correct, comprehensive, and up-to-date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or other healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.