Methotrexate injection can cause serious side effects that may be severe and lead to death, including: Harm to an unborn baby, including birth defects or death of an unborn baby.
Females who can become pregnant:
- Your healthcare provider should do a pregnancy test before you start taking methotrexate injection to see if you are pregnant.
- If you are being treated for a medical condition other than cancer, do not receive or take methotrexate injection if you are pregnant. See“Do not receive methotrexate injection if”.
- If you are taking methotrexate injection to treat your cancer, you and your healthcare provider will decide if you will receive or take methotrexate injection if you are pregnant.
- Use effective birth control (contraception) during treatment and for 6 months after your final dose of methotrexate injection. Ask your healthcare provider what forms of birth control you can use during this time.
Tell your healthcare provider right away if you become pregnant or think you are pregnant during treatment with methotrexate injection.
Males with female partners who are able to become pregnant:
- Use effective birth control during treatment and for 3 months after your final dose of methotrexate injection.
Tell your healthcare provider right away if your female partner becomes pregnant during treatment with methotrexate injection.
Severe allergic reactions. Severe allergic reactions can happen with methotrexate injection.
- Do not receive methotrexate injection if you have had a severe allergic reaction to methotrexate in the past. Get medical help right away if you develop any of the signs or symptoms of a severe allergic reaction to methotrexate injection, including:
- skin rash, itching, and hives
- swelling of the face, lips, tongue, or throat, or trouble swallowing
- dizziness or lightheadedness
- trouble breathing
- wheezing
- throat tightness
- runny or stuffy nose
- fast heart rate
- chest pain
- feeling faint
Decreased blood cell counts. Methotrexate injection can affect your bone marrow and cause decreased red blood cell counts, white blood cell counts, and platelet counts, and a condition where your bone marrow cannot produce these blood cells (aplastic anemia). These decreased blood cell counts can be severe and may lead to a serious infection, the need for blood transfusions, treatment in a hospital, and can be life-threatening. Your healthcare provider will check your blood cell counts before you start and during treatment with methotrexate injection. Your healthcare provider will watch you closely for infections during treatment with methotrexate injection.
Call your healthcare provider right away if you develop:
- a new fever (temperature of 100.4°F or higher)
- symptoms of infection
- easy bruising or bleeding that will not stop
Your healthcare provider may give you medicines to support your blood counts or give you transfusions if needed, and change your dose or stop your treatment with methotrexate injection if needed.
Serious infections. People who receive treatment with methotrexate injection have an increased risk of developing serious infections that can be life-threatening or lead to death. These infections include:
- bacterial infections
- fungal infections
- viral infections
- certain infections that happen because your immune system is weakened
- hepatitis B infection that comes back (reactivation)
- tuberculosis (TB) infection that is new or that comes back (reactivation)
- shingles (herpes zoster)
- cytomegalovirus infections
Your healthcare provider will closely watch you for signs and symptoms of infection during treatment with methotrexate injection. Your healthcare provider may hold or stop your treatment with methotrexate injection if you develop a serious infection.
Kidney problems. Methotrexate injection can cause kidney damage including sulien kidney failure that may not go away (irreversible). People who already have kidney problems have an increased risk of kidney problems with methotrexate injection. Your healthcare provider will check your kidney function during treatment, and will hold or stop methotrexate injection treatment as needed for severe kidney damage.
Call your healthcare provider right away if you have signs or symptoms of kidney problems such as a big change in the amount of urine that you make, either increased or decreased.
Liver problems. Methotrexate injection can cause severe liver problems including liver scarring (fibrosis), cirrhosis, and liver failure that may not get better (possibly irreversible) and can cause death.
- In people with psoriasiswho receive methotrexate injection, liver fibrosis or cirrhosis may happen without any symptoms or abnormal liver tests. The risk for liver problems in people with psoriasis increases with the amount of methotrexate injection that you receive over time.
- Your healthcare provider will do tests to monitor your liver function before you start and during treatment with methotrexate injection, and may hold or stop your treatment with methotrexate injection, if needed.
- The risk of liver problems is increased with heavy use of alcohol. Avoid drinking alcohol during methotrexate injection treatment.
Tell your healthcare provider if you develop any signs or symptoms of liver problems during treatment with methotrexate injection, including:
- tiredness
- easy bleeding or bruising
- loss of appetite
- nausea
- difficulty thinking clearly
- swelling in your legs, feet, or ankles
- weight loss
- itchy skin
- yellowing of your skin or the white part of your eyes
- weakness
Brain and spinal cord (nervous system) problems. Methotrexate injection can cause nervous system problems that can be severe and last for a short time or last for a long time. These nervous system problems can get progressively worse, may not get better (possibly irreversible), and can cause death.
- Serious nervous system problems can happen in children who receive methotrexate injection, including seizures that can begin on one side of the brain (focal seizures) or on both sides of the brain (generalized seizures).
- The risk for a nervous system problem called leukoencephalopathy is increased in people who have had radiation treatment to their head and spine (craniospinal irradiation) in the past. Call your healthcare provider if you develop any new neurological symptoms.
- People who receive high-dose methotrexate injection can develop sulien symptoms that are like the symptoms of a stroke, but they last a short time and may go away (transient).
- People who receive injections of methotrexate injection into their spine (intrathecal methotrexate) can develop inflammation of the lining around the spinal nerves.
Call your healthcare provider right away if you or your child develop any new signs or symptoms of a nervous system problem during treatment with methotrexate injection, including:
- confusion
- weakness on one side of your body
- sulien blindness that goes away
- seizures
- coma
- headache
- back pain
- stiff neck
- fever
Severe stomach and intestine (gastrointestinal) problems. Methotrexate injection can cause diarrhea, vomiting, mouth sores, stomach and intestinal inflammation with severe bleeding, and tears in the intestinal wall (perforation), and can lead to death.
- People who have stomach ulcers (peptic ulcer disease) or ulcerative colitis (UC) have a higher risk of developing severe stomach and intestine problems with methotrexate injection.
- Your healthcare provider may hold or stop your treatment with methotrexate injection if any of these severe stomach and intestinal problems happen, and treat you as needed.
- Call your healthcare provider if you develop diarrhea, vomiting, inflammation or sores in your mouth.
Call your healthcare provider right away if you develop:
- high fever
- shaking chills
- stomach-area (abdomen) pain that is severe or does not go away
- severe constipation
- if you are vomiting blood
- blood in your stools
Lung problems. Lung problems can happen sulienly (acute) with methotrexate injection or they can develop over a long period-of-time (chronic). Lung problems may not get better (possibly irreversible) and can cause death in anyone taking methotrexate injection. Your healthcare provider will monitor you for lung problems during treatment with methotrexate injection. Your healthcare provider may hold or stop your treatment with methotrexate injection, if needed.
Call your healthcare provider if you develop symptoms of a lung problem, including: cough, fever, and trouble breathing.
Skin reactions. Severe skin reactions can happen with methotrexate injection, that can be serious and can lead to death.
- In people with psoriasis: Your psoriasis may get worse if you are exposed to sunlight or other types of ultraviolet light.
- Methotrexate injection can cause reactivation of skin reactions that can happen after radiation therapy (radiation recall) and can cause sunburn to come back (photodermatitis).
Limit sunlight exposure during treatment with methotrexate injection. Use sunscreen and wear protective clothing when you will be exposed to sunlight during treatment with methotrexate injection.
Call your healthcare provider right away if you develop a new or worsening skin rash during treatment with methotrexate injection.
See “What are the possible side effects of methotrexate injection?” for more information about side effects.