Introduction
A number of illnesses make it necessary to take methotrexate. Especially if NSAIDs (non-steroidal anti-inflammatory drugs) are not responded to, methotrexate therapy may be indicated. However, methotrexate can also be used to treat active rheumatoid arthritis or severe forms of psoriasis.
Methotrexate belongs to the group of active ingredients of specific antirheumatic drugs and is administered in syringe form. It is administered either into the muscle, under the skin, or into a vessel, i.e. an artery or vein. However, oral administration, i.e. taking the drug by mouth, is also possible. However, methotrexate causes side effects, just like any other medication, if the appropriate conditions or contraindications are not observed.
Mode of action
Methotrexate (often also abbreviated: MTX) is a cell poison and has a cytostatic effect. This means that it slows down the proliferation of cells by inhibiting the formation of tetrahydrofolic acid. Tetrahydrofolic acid is needed to form purines and thymidines.
Anyone who paid close attention in biology lessons will know what to do by now at the latest: Purines are the nucleic bases guanine and adenine, thymidine is part of the nucleic base thymine. Together with cytosine, these three form the basic structure of DNA. However, if methotrexate inhibits the formation of three of the four nucleic bases of DNA, no functioning DNA can be produced.
The consequence is that cell division is stopped. Because if the genetic code from which a cell is built cannot be passed on, no cell can be produced. Methotrexate is mainly used in cancer therapy, in the treatment of autoimmune diseases, and in ectopic pregnancies.
Autoimmune diseases include rheumatoid arthritis, systemic lupus erythematosus, Crohn’s disease, and ankylosing spondylitis. But also psoriasis, multiple sclerosis, and Boeck’s disease can be treated with methotrexate. Since methotrexate intervenes very deeply in the cell cycle, it unfortunately also causes a number of side effects.
Side effects
To illustrate: Methotrexate leads to mood swings in “rare” cases. This means that at least every ten thousandth, but at most every thousandth patient has suffered from this side effect after taking it in test series. In the case of Methotrexate there are many different side effects that can affect the skin, eyes, lungs, hair, psyche, and pregnancy.
- “Very rare” side effects occur in less than one in 10,000 patients tested.
- “Rare” side effects occur in every thousandth to ten thousandth patient.
- “Occasional” side effects indicate an occurrence in every thousandth to one hundredth patient tested.
- “Common” side effects occur in every tenth to one hundredth patient.
- “Very common” side effects are those that can occur in one in ten patients, i.e. 10% of methotrexate intake.
In rare cases, the eye may be severely impaired. In very rare cases, retinopathy, i.e. the death of the retina, and conjunctivitis may even occur. In the lungs, pneumonia often occurs in combination with fever, chest pain, shortness of breath to shortness of breath, and dry irritable cough.
Occasionally, pulmonary fibrosis can also occur. Pulmonary fibrosis is an increase in the connective tissue in the lungs, which makes it difficult for oxygen to diffuse into the blood. As a result, the amount of oxygen in the blood is permanently reduced.
In extremely rare cases, taking methotrexate can cause serious side effects in the lungs. Taking the drug can lead to a special type of pneumonia, which is then also known as Mtx-Pneuomonitis. The first signs of pneumonia caused by methotrexate may be a dry irritable cough, which is more frequent in connection with the intake of the drug.
Other symptoms may include shortness of breath and pain when breathing. In such a case, the doctor who prescribed the methotrexate should be consulted as soon as possible. If necessary, the doctor will have an X-ray of the lungs (chest X-ray) made.
In this way it is usually easy to determine whether or not there is an inflammation of the lungs. If there are changes in the X-ray image that indicate Mtx pneumonitis, the medication must usually be discontinued. Methotrexate leads to a wide range of side effects that result in changes in the skin.In rare cases, acne and pigment changes of the nails occur.
Occasionally, i.e. in 1% to 0.1% of cases, there is increased sensitivity to light, herpes reactions, not only on the lip, and hair loss. Hair loss is particularly stressful for the patients, as hair on the head is part of the patient’s appearance and personality. In surveys, hair loss, together with nausea, has been reported as one of the most subjectively serious side effects of methotrexate therapy.
Many patients suffer from it so much that they discontinue the therapy. In the case of hair loss, it is therefore particularly important to accompany the patient on his way and to show him treatment options. These can be for example the use of wigs.
Human hair wigs and toupees can conceal hair loss well. But also a bald head can look visually appealing. Therefore, psychological support is important.
Taking methotrexate can cause damage to the nerve tracts in the body. This side effect, known as polyneuropathy, can manifest itself as pain, tingling and paresthesia, especially in the arms or legs. Often the symptoms of polyneuropathy first appear on the feet or hands and then, over time, increase towards the trunk.
If polyneuropathy occurs while taking methotrexate, a causal connection is possible but not certain. A nerve damage can have many other causes. The most common causes of polyneuropathy are diabetes and regular alcohol consumption.
If the above-mentioned symptoms of polyneuropathy occur while taking methotrexate, the physician must therefore assess whether the medication should continue to be taken or should be discontinued. Mild side effects of Methotrexate on the central nervous system (CNS) are quite common and can occur in up to one in ten patients. Typical symptoms include fatigue, drowsiness or headaches.
Occasionally (in a maximum of one in 100 users), dizziness, confusion or even organ damage to the brain (encephalopathy) and seizures can occur as a result of taking Methotrexate. Very rare possible side effects are changes in taste, pain and discomfort or tingling in arms and legs and muscle weakness. Also very rare is the occurrence of meningitis.
Typical symptoms are very severe headaches, nausea, vomiting, neck stiffness and clouding of consciousness. If methotrexate is used in a tumor disease, in rare cases there may also be side effects on the CNS, leading to paralysis or speech disorders. If such more serious side effects occur, the treating physician must be contacted immediately.
Methotrexate can occasionally cause side effects on the bladder. This can lead to cystitis, which can be manifested by pain when urinating and possibly bloody urine. An emptying disorder of the bladder can also be a symptom.
In case of such symptoms, the treating physician should be consulted. This doctor should assess whether or not the symptoms could be due to taking medication. If so, the dose may have to be reduced or methotrexate discontinued completely.
Bladder infections are not uncommon, especially in women, so that a change in medication is often not indicated. Methotrexate quite often leads to mild side effects on the liver. This is partly because the drug is metabolized by the liver, where it can damage the tissue, and partly because it can lead to an inflammatory reaction in the liver.
Often there are no complaints or symptoms and the side effects of Methotrexate on the liver are only noticeable by an increase in liver values when the blood is checked in the laboratory. Often such a slight increase is not serious and the drug can be continued to be taken. However, if in the opinion of the doctor the side effects on the liver are too pronounced or even symptoms appear, the drug must be discontinued.
If the examination reveals side effects in the liver, there may be many other causes besides methotrexate. Often such a slight increase is not serious and the medication can be continued. However, if in the opinion of the physician the side effects on the liver are too pronounced or even symptoms appear, the drug must be discontinued.However, if side effects are found in the liver during the examination, there may be many other causes besides methotrexate.
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