The Unexpected Side Effects of Methotrexate: A Comprehensive Guide
Methotrexate is a prescription medication belonging to a class of drugs called antimetabolites. Doctors prescribe methotrexate to treat cancer and diseases caused by an overactive immune system, such as rheumatoid arthritis, Psoriatic Arthritis, and psoriasis. While methotrexate may be effective in treating these conditions, it also causes several side effects, ranging in severity from mild to life-threatening.
Common Side Effects of Methotrexate
You may experience these common side effects of methotrexate when you begin to take the medicine:
- Nausea
- Vomiting
- Stomach upset
- Diarrhea
- Loss of appetite
- Hair loss
- Mouth sores
- Chills
- Fever
- Tiredness
- Headaches
- Sun sensitivity
- Rashes
- Stuffy nose
- Sore throat
- Painful sores in the skin
- Cough
Less common side effects of methotrexate include:
- Acne
- Back pain
- Blurred vision
- Dark urine
- Dizziness
- Lower back pain
- Confusion
- seizures
Generally, the severity of these symptoms depends on the dose of methotrexate used and how often it is taken. Nonetheless, these symptoms are usually mild and transient, resolving after a couple of days or weeks. However, if the symptoms become severe or persistent, contact your doctor for treatment.
Serious Side Effects of Methotrexate
The serious side effects of methotrexate usually require urgent medical attention. If you develop any of these side effects, consult your doctor immediately. These symptoms include:
1. Abnormal Bleeding
This could be presented in the following ways:
- Coughing up blood
- Vomiting blood or a substance that looks like coffee grounds
- Bloody stools or black, tarry stools
- Bleeding from your gums
- Easy bruising and prolonged bleeding from injuries
- Abnormal vaginal bleeding
2. Allergic reaction
Not everyone develops allergies to methotrexate. When it occurs it may be life-threatening. Common symptoms of allergy to methotrexate include:
- Difficulty breathing
- Hives
- Swelling of your throat
If you have ever had an allergic reaction to methotrexate, do not use it again. Retaking it may cause death.
3. Skin reactions
Methotrexate may cause serious skin reactions that may include:
- Rashes
- Swelling
- Blisters
- peeling skin
In addition to these skin reactions, methotrexate also makes the skin more sensitive to the sun, causing sunburn. As a result of this effect, if you take methotrexate, avoid the sun if you can apply sunscreen, or wear protective clothing.
As a result of this increased sun sensitivity, people who have psoriasis that gets worse with exposure to sunlight or ultraviolet radiation should avoid methotrexate.
4. Infections
Methotrexate impairs the division of immune cells and this may increase one’s risk of infections. Common symptoms of infection include:
- Fever
- Chills
- Cough
- Ear pain and discharge
- Cough that may be productive of purulent sputum
- Pain while urinating
- Mouth sores
Because of its ability to suppress the bone marrow (the tissue within the bone that produces blood cells) and, in turn, reduce the level of immune cells in the blood, people with suppressed immunity due to certain illnesses, such as diabetes or HIV, should not take methotrexate. People with an active infection should also avoid methotrexate because of this.
Furthermore, people who have been diagnosed with anemia of any cause should not take methotrexate because of its ability to suppress the production of red blood cells.
5. Lung Lesions
Methotrexate may cause sores to develop in the lungs, causing the following symptoms:
- Dry cough
- Fever
- Difficulty breathing
6. Tumor Lysis Syndrome
Tumor lysis syndrome is a complication of treating rapidly growing tumors. It results from a chemical disturbance in the blood. When anti-cancer drugs destroy large amounts of cancer cells, they release certain chemicals into the blood in large amounts and these cause several signs and symptoms including:
- Muscle cramps
- Twitches
- Fatigue
- Diarrhea
- Restlessness
- Hallucinations
- Seizures
- Confusion
- Irregular heart rate.
If you use methotrexate with other medicines, such as aspirin, phenytoin, azathioprine, probenecid, and omeprazole, these medicines may increase your risk and the severity of these effects.
Long-Term Side Effects of Methotrexate
These side effects occur after prolonged use of the medicine and may require discontinuation of the drug. These side effects include:
1. Liver disease
Problems with the liver present with the following symptoms:
- Dark-colored urine
- Abdominal pain
- Vomiting
- Light-colored stools
- Yellowness of the skin and whites of the eyes
- Fatigue
Because methotrexate causes liver damage, people with liver disease are advised not to use the medicine. Furthermore, taking alcohol with methotrexate can worsen the damage it does to the liver.
2. Kidney Disease
Damage to the kidney may cause the following symptoms:
- Pain in the flanks
- Reduced urination
- Fluid retention causes facial fullness or swollen legs and feet
- Blood in urine
As a result of methotrexate’s effect on the kidneys, the drug is not recommended for people with a current or past history of kidney disease. This is partly because having kidney problems impairs the elimination of the drug from the system, worsening its side effects. If methotrexate is absolutely necessary, the doctor may adjust the dose based on the health of the kidney.
3. Damage to the Pancreas
Methotrexate can damage the pancreas, causing the following symptoms:
- Severe back pain
- Severe abdominal pain
- Vomiting
4. Sores in the Stomach and Intestines
After prolonged use, methotrexate could cause sores or ulcers in the inner walls of the stomach and intestines. This could worsen conditions such as stomach ulcers or ulcerative colitis.
4. Cancer
Although rarely, methotrexate may increase the risk of a type of cancer called lymphoma; a type of cancer that affects the immune cells, the lymphocytes. Symptoms of lymphoma include:
- Fever
- Weakness
- Enlarged lymph nodes
- Drenching night sweats
- Weight loss
5. Bone Loss
Prolonged use of methotrexate causes loss of bone density. This may produce the following symptoms:
- Bone weakness
- Bone pain
- Fractures
6. Bone Marrow Damage
Methotrexate may cause damage to the bone marrow, the tissue that produces new blood cells. There are three types of cells in the blood – red blood cells, white blood cells, and platelets; these serve different functions. When the production of these cells is impaired, the following symptoms occur:
- Reduced red blood cell levels: This is called anemia and may manifest with symptoms of pale skin and white eyes, tiredness, shortness of breath, and a fast heart rate.
- Reduced white blood cell levels. This may increase one’s risk of infections, as noted earlier.
- Reduced platelet levels: platelets play a major role in forming blood clots. So if deficient, may cause abnormal or prolonged bleeding.
7. Infertility
Since methotrexate inhibits the production of DNA and the division of rapidly dividing cells, it will affect the production of sperm cells. As a result, men who use methotrexate may develop low sperm count and an inability to father a child.
Conclusion:
Methotrexate is a prescription medicine that doctors prescribe for treating cancer and diseases caused by a hyperactive immune system like Psoriasis and Psoriatic Arthritis. While the drug may be therapeutically effective, it also has several adverse effects. It is important to speak with your doctor if you notice any changes in your body while taking the drug and seek his or her advice before taking another medication with it.
References
- https://www.nhs.uk/medicines/methotrexate/side-effects-of-methotrexate/
- https://www.drugs.com/methotrexate.html
- https://www.arthritis.org/health-wellness/treatment/treatment-plan/disease-management/methotrexate-managing-side-effects
- Hanoodi M, Mittal M. Methotrexate. [Updated 2023 Aug 16]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK556114/