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Methotrexate (as disodium methotrexate).

Yellow, round, uncoated, flat tablet, scored and engraved with ORN 57 on one side.
Each tablet contains: Active ingredients: Methotrexate 2,5mg (as disodium methotrexate).
Excipients/Inactive Ingredients: Lactose monohydrate, microcrystalline cellulose, magnesium stearate.

Pharmacotherapeutic groups: Other immunosuppressants. ATC code: L04AX03.
Pharmacology: Pharmacodynamics: Methotrexate (4-amino-10-methylfolic acid) is a folic acid antagonist that inhibits the reduction of folic acid leading to decreased cellular proliferation. Methotrexate enters the cell through an active transport mechanism of reduced folates.
As a result of the polyglutamylation of methotrexate caused by the folylpolyglutamate synthetase enzyme, the duration of the cytotoxic effect of the drug substance in the cell increases. Methotrexate is a phase-specific substance the main action of which is directed to the S-phase of cell mitosis. It acts generally most effectively on actively proliferating tissues, such as malignant cells, bone marrow, fetal cells, skin epithelium, oral and intestinal mucosa as well as urinary bladder cells. As the proliferation of malignant cells is faster than that of most normal cells, methotrexate can slow down the proliferation of malignant cells without causing irreversible damage to normal tissue.
Calcium folate is a folinic acid that is used to protect normal cells from the toxic effects of methotrexate. Calcium folate enters the cell through a specific transport mechanism, is converted in the cell into active folates, and reverses the inhibition of the synthesis of precursors of DNA and RNA.
Pharmacokinetics: Absorption: The effect of orally administered methotrexate is dependent on the size of the dose. Peak concentrations in serum are reached within 1-2 hours. Generally, a dose of methotrexate of 30 mg/m² or less is absorbed rapidly and completely. The bioavailability of orally administered methotrexate is high (80-100%) at doses of 30 mg/m² or less. At doses above 30 mg/m² absorption becomes nonlinear and absorption at doses exceeding 80 mg/m² is incomplete.
Distribution: Approximately 50% of methotrexate is bound to serum proteins. Upon being distributed into body tissues, high concentrations in the form of polyglutamate are found in the liver, kidneys, and spleen in particular, which can be retained for weeks or months. When administered in small doses, methotrexate passes into the liquor in minimal amounts.
Metabolism: Approx. 10% of the administered methotrexate dose is metabolized in the liver. The principle metabolite is 7-hydroxymethotrexate.
Elimination: Excretion takes place, mainly in unchanged form, primarily via glomerular filtration and active secretion in the proximal tubule.
Approx. 5-20% methotrexate and 1-5% 7-hydroxy methotrexate are eliminated biliary with pronounced enterohepatic circulation.
The terminal half-life is on average 6-7 hours and demonstrates considerable variation (3-17 hours). The half-life can be prolonged to 4 times the normal length in patients who possess a third distribution space (pleural effusion, ascites).
Special populations: In the case of renal insufficiency, elimination is delayed significantly.

Active rheumatoid arthritis in adult patients.
Severe recalcitrant disabling psoriasis, which is not adequately responsive to other forms of therapy such as phototherapy, PUVA, and retinoids, and severe psoriatic arthritis in adult patients.
Maintenance treatment of acute lymphoblastic leukemia in adults, adolescents and children aged 3 years and over.

Posology: Methotrexate should only be prescribed by physicians with expertise in the use of methotrexate and a full understanding of the risks of methotrexate therapy.
Important warning concerning the dosing of methotrexate: See Warnings.
Rheumatoid arthritis: The usual dose is 7.5-15 mg once weekly. The dose may be adjusted gradually to achieve an optimal response but should not exceed a total weekly dose of 25 mg. Doses exceeding 20 mg per week can be associated with a significant increase in toxicity, especially bone marrow suppression. Thereafter the dose should be reduced to the lowest possible effective dose which in most cases is achieved within 6 weeks.
Psoriasis: Before starting treatment it is advisable to give the patient a test dose of 2.5-5.0 mg to exclude unexpected toxic effects. If, one week later, appropriate laboratory tests are normal, treatment may be initiated. The usual dose is 7.5-15 mg taken once weekly. As necessary, the total weekly dose can be increased up to 25 mg. Doses exceeding 20 mg per week can be associated with a significant increase in toxicity, especially bone marrow suppression. Thereafter the dose should be reduced to the lowest effective dose according to therapeutic response which in most cases is achieved within 4 to 8 weeks.
The patient should be fully informed of the risks involved and the clinician should pay particular attention to the appearance of liver toxicity by carrying out liver function tests before starting methotrexate treatment, and repeating these during therapy. The aim of therapy should be to reduce the dose to the lowest possible level with the longest possible rest period. The use of methotrexate may permit the return to conventional topical therapy.
Cytostatic: Dosage in acute lymphoblastic leukemia: Low-dose methotrexate is used in the maintenance treatment of acute lymphoblastic leukemia in children aged 3 years and over, adolescents and adults within complex protocols in combination with other cytostatic medicinal products. Treatment should follow current therapy protocols.
Common accepted single doses lie in the range of 20-40 mg/m² body surface area and are usually given once weekly.
If methotrexate is administered in combination with chemotherapy regimens, the dosage should take into consideration any overlapping toxicity of the other medicinal product components.
Higher dosages should be given parenterally.
Pediatric population: Methotrexate should be used with caution in pediatric patients. Treatment should follow currently valid therapy protocols for children.
Doses are usually based on the patient's body surface area and maintenance treatment represents a long-term treatment.
The use in children below 3 years of age is not recommended as insufficient data on efficacy and safety are available for this population.
Special populations: Use in elderly patients: Methotrexate should be used with extreme caution in elderly patients, a dose reduction should be considered due to reduced liver and kidney function as well as lower folate reserves which occur with increased age.
Patients with renal impairment: Methotrexate should be used with caution in patients with impaired renal function. The dose should be adjusted as follows: Dosage recommendations (see Table 1).


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Patients with hepatic impairment: Methotrexate should be administered with great caution, if at all, to patients with significant current or previous liver disease, especially if due to alcohol. Methotrexate is contraindicated in patients with significantly impaired hepatic function.
Use in patients with a third distribution space (pleural effusions, ascites): As the half-life of methotrexate can be prolonged to 4 times the normal length in patients who possess a third distribution space dose reduction or, in some cases, discontinuation of methotrexate administration may be required.
Special note: If changing the oral application to parenteral administration a reduction of the dose may be required due to the variable bioavailability of methotrexate after oral administration.
Folic acid or folinic acid supplementation may be considered according to current treatment guidelines.

Symptoms: Toxicity of methotrexate mainly affects the hematopoietic and gastrointestinal systems. Symptoms include leukopenia, thrombocytopenia, anemia, pancytopenia, neutropenia, bone marrow depression, mucositis, stomatitis, oral ulceration, nausea, vomiting, gastrointestinal ulceration, and gastrointestinal bleeding. Some patients showed no signs of overdose.
There are reports of death due to sepsis, septic shock, renal failure, and aplastic anemia.
Cases of overdose have been reported, sometimes fatal, due to erroneous daily intake instead of weekly intake of oral methotrexate. In these cases, symptoms that have been commonly reported are hematological and gastrointestinal reactions.
Treatment: Calcium folate is the specific antidote for neutralizing the toxic undesirable effects of methotrexate.
In cases of accidental overdose, a dose of calcium folinate equal to or higher than the offending dose of methotrexate should be administered intravenously or intramuscularly within one hour Observation of serum methotrexate concentrations is relevant in determining the right dose of calcium folate and the duration of the therapy.
In cases of massive overdose, hydration, and urinary alkalisation may be necessary to prevent precipitation of methotrexate and/or its metabolites in the renal tubules. Neither hemodialysis nor peritoneal dialysis has been shown to improve methotrexate elimination. Effective clearance of methotrexate has been reported with acute, intermittent hemodialysis using a high flux dialyzer.

Hypersensitivity to methotrexate or any excipients of the drug.
Significantly impaired hepatic function.
Alcoholism.
Significantly impaired renal function.
Pre-existing blood disorders, such as bone marrow hypoplasia, leukopenia, thrombocytopenia, or significant anemia.
Severe acute or chronic infections and immunodeficiency syndromes.
Stomatitis, ulcers of the oral cavity and known active gastrointestinal ulcer disease.
Breastfeeding women.
During methotrexate therapy concurrent vaccination with live vaccines must not be carried out.
Contraindicated in pregnancy for non-oncological indications.

Important warning concerning the dosing of methotrexate: In the treatment of rheumatic diseases, psoriasis or severe psoriatic arthritis, methotrexate must only be taken once a week. Dosage errors in the use of methotrexate can result in serious adverse reactions, including death. Read this monograph very carefully.
The prescriber should ensure that patients or their carers will be able to comply with the once-weekly regimen.
It must be explicitly pointed out to the patient that for the therapy of rheumatic diseases, psoriasis or severe psoriatic arthritis methotrexate is administered only once a week.
The prescriber should specify the day of intake on the prescription.
Methotrexate elimination is reduced in patients with a third distribution space (ascites, pleural effusions). Such patients require especially careful monitoring for toxicity and require dose reduction or, in some cases, discontinuation of methotrexate administration.

Dosing in the treatment of rheumatoid arthritis, psoriasis and severe psoriatic arthritis: The patients should be informed clearly that in the treatment of rheumatoid arthritis, psoriasis or severe psoriatic arthritis the administration is once weekly.
The prescriber should specify the day of intake on the prescription.
The prescriber should make sure patients understand that methotrexate tablets should only be taken once a week. Patients should be instructed on the importance of adhering to the once-weekly intakes.
Warnings: Methotrexate should only be administered by physicians experienced in antimetabolite chemotherapy.
Concomitant administration of hepatotoxic or haematotoxic DMARDs (disease-modifying antirheumatic drug, e.g. leflunomide) is not advisable.
Due to the possibility of fatal or severe toxic reactions, the patient should be fully informed by the physician of the risks involved and be under constant supervision. Patients must be appropriately monitored during treatment so that signs of possible toxic effects or adverse reactions can be detected and evaluated with minimal delay.
Especially strict monitoring of the patient is indicated following prior radiotherapy (especially of the pelvis), functional impairment of the haematopoietic system (e.g., following prior radio- or chemotherapy), impaired general condition as well as advanced age and in very young children.
Because of the possibility of severe or even fatal toxic reactions, patients should be extensively informed by the treating doctor of the risks involved (including early signs and symptoms of toxicity) and the recommended safety measures. Patients should be informed that they must notify the doctor immediately if any symptoms of an overdose occur and that the symptoms of the overdose need to be monitored (including regular laboratory tests).
Doses exceeding 20 mg/week can be associated with a substantial increase in toxicity, especially bone marrow depression.
Because of the delayed excretion of methotrexate in patients with impaired kidney function, they should be treated with particular caution and only with low doses of methotrexate.
Fertility and reproduction: Fertility: Methotrexate has been reported to cause impairment of fertility, oligospermia, menstrual dysfunction and amenorrhoea in humans during and for a short period after the discontinuation of treatment, affecting spermatogenesis and oogenesis during the period of its administration - effects that appear to be reversible on discontinuing therapy.
Teratogenicity - Reproductive risk: Methotrexate causes embryotoxicity, abortion and foetal malformations in humans. Therefore, the possible effects on reproduction, pregnancy loss and congenital malformations should be discussed with male and female patients of childbearing age. In non-oncologic indications, the absence of pregnancy must be confirmed before methotrexate is used. If women of a sexually mature age are treated, effective contraception must be used during treatment and for at least six months after.
Methotrexate should be used only with great caution, if at all, in patients who have a significant liver disease, particularly if this is/was alcohol-related.
Recommended examinations and safety measures: Before beginning treatment or resuming treatment after a recovery period: Complete blood count with differential blood count and platelets, liver enzymes, bilirubin, serum albumin, chest X-ray and renal function tests. If clinically indicated, tuberculosis and hepatitis B and C should be excluded.
During treatment: The tests as follows must be conducted weekly in the first two weeks, then every two weeks for a month; thereafter, depending on the leucocyte count and the stability of the patient, at least once a month during the next six months and then at least every three months. An increased monitoring frequency should be considered when the dose is increased. In particular, elderly patients should be monitored at short intervals for early signs of toxicity.
Examination of the mouth and throat for mucosal changes.
Complete blood count with differential blood count and platelets. Methotrexate-induced hematopoietic suppression may occur abruptly and with apparently safe dosages. Any serious decrease in leucocyte or platelet counts indicates the immediate discontinuation of treatment and appropriate supportive therapy. Patients should be encouraged to report all signs and symptoms suggestive of infection to their doctor. In patients simultaneously taking hematotoxic medicinal products (e.g. leflunomide), blood count and platelets should be closely monitored.
Liver function tests: Particular attention should be given to the appearance of liver toxicity. Treatment should not be initiated or should be discontinued if there are persistent or significant abnormalities in liver function tests, other noninvasive investigations of hepatic fibrosis, or liver biopsies.
Temporary increases in transaminases to two or three times the upper limit of normal have been reported in patients at a frequency of 13-20%. Persistent elevation of liver enzymes and/or decrease in serum albumin may be indicative for severe hepatotoxicity. In the event of a persistent increase in liver enzymes, consideration should be given to reducing the dose or discontinuing therapy.
Histological changes, fibrosis and more rarely liver cirrhosis may not be preceded by abnormal liver function tests. There are instances in cirrhosis where transaminases are normal. Therefore, non-invasive diagnostic methods for monitoring of liver condition should be considered, in addition to liver function tests. Liver biopsy should be considered on an individual basis taking into account the patient's comorbidities, medical history and the risks related to biopsy. Risk factors for hepatotoxicity include excessive prior alcohol consumption, persistent elevation of liver enzymes, history of liver disease, family history of hereditary liver disorders, diabetes mellitus, obesity and previous contact with hepatotoxic drugs or chemicals and prolonged methotrexate treatment.
Additional hepatotoxic medicinal products should not be given during treatment with methotrexate unless clearly necessary. Alcohol consumption should be avoided. Closer monitoring liver enzymes should be undertaken in patients concomitantly taking other hepatotoxic medicinal products.
Increased caution should be exercised in patients with insulin-dependent diabetes mellitus, as during methotrexate therapy, liver cirrhosis developed in isolated cases without any elevation of transaminases.
Renal function: Should be monitored by renal function tests and urinalysis. If serum creatinine levels are increased, the dose should be reduced. If creatinine clearance is less than 30 mL/min, treatment with methotrexate should not be given. Treatment with moderately high and high doses of methotrexate should not be initiated at urinary pH values of less than 7.0. Alkalinization of the urine must be tested by repeated pH monitoring (value greater than or equal to 6.8) for at least the first 24 hours after the administration of methotrexate is started.
Respiratory tract examination: Patients must be monitored for symptoms of a lung function disorder and lung function tests performed if necessary. Lung-related symptoms (particularly a dry, non-productive cough) or non-specific pneumonitis that occurs during treatment with methotrexate can be a sign of potentially dangerous damage and require the discontinuation of treatment and careful monitoring. Although the clinical presentation is variable, patients with methotrexate-induced lung diseases typically suffer from fever, cough, dyspnoea, or hypoxemia. A chest X-ray must be taken to be able to exclude an infection. Acute or chronic interstitial pneumonia, often in association with blood eosinophilia, may occur and deaths have been reported. Patients should be informed of the risks of pneumonia and advised to contact their doctor immediately if they develop a persistent cough or persistent dyspnoea.
In addition, pulmonary alveolar hemorrhage has been reported with methotrexate used in rheumatologic and related indications. This event may also be associated with vasculitis and other comorbidities. Prompt investigations should be considered when pulmonary alveolar hemorrhage is suspected to confirm the diagnosis.
Methotrexate should be discontinued in patients with pulmonary symptoms and an immediate examination (including chest X-ray) should be performed to exclude infection and tumors. If methotrexate-induced lung disease is suspected, treatment with corticosteroids should be initiated and treatment with methotrexate should not be restarted.
Pulmonary symptoms require a rapid diagnosis and discontinuation of methotrexate therapy. Methotrexate-induced lung diseases such as pneumonitis can occur acutely and at any time during treatment, are not always completely reversible and have already been observed at all doses (including low doses of 7.5 mg/week).
Opportunistic infections can occur during treatment with methotrexate, including Pneumocystis jirovecii pneumonia, which can also have a fatal outcome. If a patient develops pulmonary symptoms, the possibility of Pneumocystis jirovecii pneumonia should be considered.
Particular caution is required in patients with impaired pulmonary function.
Particular caution is also required in the presence of inactive chronic infections (e.g. herpes zoster, tuberculosis, hepatitis B or C) as it is possible that activation of these infections may occur.
Renal impairment and patients at risk of renal impairment: As methotrexate is eliminated mainly via the kidneys, increased concentrations are to be expected in the presence of renal impairment, which may result in severe adverse reactions.
If there is the possibility of renal impairment (e.g. in elderly subjects), monitoring should take place at shorter intervals. This applies in particular when medicinal products that affect the elimination of methotrexate, that cause kidney damage (e.g. NSAIDs) or that can potentially lead to impairment of hematopoiesis, are administered concomitantly.
If risk factors such as renal function disorders, including mild renal impairment, are present, combined administration with NSAIDs is not recommended. Dehydration may also intensify the toxicity of methotrexate. (See renal function as previously mentioned).
Immune system: Due to its effect on the immune system, methotrexate may impair the response to vaccinations and affect the results of immunological tests. Concurrent vaccination using live vaccines should not be given.
Malignant lymphomas: Malignant lymphomas may occur in patients receiving low dose methotrexate, in which case therapy must be discontinued. If the lymphomas fail to regress spontaneously, cytotoxic treatment must be initiated.
Pleural effusions or ascites: Pleural effusions and ascites should be drained before initiation of methotrexate treatment.
Conditions that cause dehydration such as vomiting, diarrhea or stomatitis: Conditions that cause dehydration such as vomiting, diarrhea or stomatitis can increase toxicity as a result of raised active substance levels. In this case, treatment with methotrexate must be discontinued until the symptoms have disappeared.
It is important to determine any increase in active substance levels within 48 hours of therapy, otherwise irreversible methotrexate toxicity may occur.
Diarrhea and ulcerative stomatitis may be signs of toxic effects and require the discontinuation of treatment, otherwise, hemorrhagic enteritis and death from intestinal perforation may occur. Following the occurrence of haematemesis, black-colored stools or blood in the stools, treatment must be discontinued.
Folic acid supplementation: If acute methotrexate toxicity occurs, patients may require treatment with folinic acid. In patients with rheumatoid arthritis or psoriasis, folic acid or folinic acid supplementation may reduce methotrexate toxicity, such as gastrointestinal symptoms, stomatitis, alopecia and elevated liver enzymes.
It is recommended to check levels of vitamin B12 prior to initiating folic acid supplementation, particularly in adults aged over 50 years, as folic acid intake may mask a vitamin B12 deficiency.
Vitamin products: Vitamin preparations or other products containing folic acid, folinic acid or their derivatives may decrease the effectiveness of methotrexate.
Dermatitis and sunburn: Radiation-induced dermatitis and sunburn can reappear during methotrexate therapy (recall reactions). Psoriatic lesions can worsen during UV radiation and co-administration of methotrexate.
Skin toxicity: Severe, occasionally fatal, dermatologic reactions, including toxic epidermal necrolysis (Lyell's syndrome) or Stevens-Johnson syndrome have been reported after single or multiple doses of methotrexate.
Encephalopathy/leukoencephalopathy: Since cases of encephalopathy/leukoencephalopathy have occurred in cancer patients treated with methotrexate, this cannot be ruled out either for patients with non-cancer indications.
Progressive multifocal leukoencephalopathy (PML): Cases of progressive multifocal leukoencephalopathy (PML) have been reported in patients using methotrexate, mostly in combination with other immunosuppressive agents. PML can be fatal and should be considered in the differential diagnosis of immunosuppressed patients presenting with new or worsening neurological symptoms.
Lactose excipient warning: This medication contains lactose. Patients with rare hereditary conditions such as galactose intolerance, total lactase deficiency, or glucose-galactose malabsorption should not take this medicine.
Effects on Ability to Drive and Use Machines: Central nervous system symptoms, such as fatigue and dizziness, can occur during treatment with methotrexate which has a minor or moderate influence on the ability to drive and use machines.
Use in Pregnancy & Lactation: See Use in Pregnancy & Lactation section for further information.

Women of childbearing potential/contraception in females: Women must not get pregnant during methotrexate therapy and effective contraception must be used during treatment with methotrexate and at least 6 months thereafter.
Prior to initiating therapy, women of childbearing potential must be informed of the risk of malformations associated with methotrexate and any existing pregnancy must be excluded with certainty by taking appropriate measures, e.g. a pregnancy test. During treatment pregnancy tests should be repeated as clinically required (e.g. after any gap of contraception). Female patients of reproductive potential must be counselled regarding pregnancy prevention and planning.
Contraception in males: It is not known if methotrexate is present in semen. Methotrexate has been shown to be genotoxic in animal studies, such that the risk of genotoxic effects on sperm cells cannot completely be excluded. Limited clinical evidence does not indicate an increased risk of malformations or miscarriage following paternal exposure to low-dose methotrexate (less than 30 mg/week). For higher doses, there is insufficient data to estimate the risks of malformations or miscarriage following paternal exposure.
As precautionary measures, sexually active male patients or their female partners are recommended to use reliable contraception during treatment of the male patient and for at least 6 months after cessation of methotrexate. Men should not donate semen during therapy or for 6 months following discontinuation of methotrexate.
Pregnancy: Methotrexate is contraindicated during pregnancy in non-oncological indications. If pregnancy occurs during treatment with methotrexate and up to six months thereafter, medical advice should be given regarding the risk of harmful effects on the child associated with treatment, and ultrasonography examinations should be performed to confirm normal fetal development.
In animal studies, methotrexate has shown reproductive toxicity, especially during the first trimester. Methotrexate has been shown to be teratogenic to humans; it has been reported to cause fetal death, miscarriages, and/or congenital abnormalities (craniofacial, cardiovascular, central nervous system, and extremity-related). Methotrexate is a powerful human teratogen, with an increased risk of spontaneous abortions, intrauterine growth restriction, and congenital malformations in case of exposure during pregnancy.
Spontaneous abortions have been reported in 42.5% of pregnant women exposed to low-dose methotrexate treatment (less than 30 mg/week), compared to a reported rate of 22.5% in disease-matched patients treated with drugs other than methotrexate.
Major birth defects occurred in 6.6% of live births in women exposed to low-dose methotrexate treatment (less than 30 mg/week) during pregnancy, compared to approximately 4% of live births in disease-matched patients treated with drugs other than methotrexate.
Insufficient data is available for methotrexate exposure during pregnancy higher than 30 mg/week, but higher rates of spontaneous abortions and congenital malformations are expected, in particular at doses commonly used in oncologic indications.
When methotrexate was discontinued prior to conception, normal pregnancies have been reported.
When used in oncological indications, methotrexate should not be administered during pregnancy in particular during the first trimester of pregnancy. In each individual case, the benefit of treatment must be weighed up against the possible risk to the fetus. If the drug is used during pregnancy or if the patient becomes pregnant while taking this methotrexate the patient should be informed of the potential risk to the foetus.
Breastfeeding: As methotrexate passes into breast milk and may cause toxicity in nursing infants, treatment is contraindicated during the lactation period. Breast-feeding is therefore to be stopped prior to treatment.
Fertility: Methotrexate affects spermatogenesis and oogenesis and may decrease fertility. In humans, methotrexate has been reported to cause oligospermia, menstrual dysfunction, and amenorrhoea. These effects appear to be reversible after discontinuation of therapy in most cases. In oncologic indications, women who are planning to become pregnant are advised to consult a genetic counseling center, if possible, prior to therapy and men should seek advice about the possibility of sperm preservation before starting therapy as methotrexate may be genotoxic at higher doses.

Generally, the frequency and severity of adverse reactions are dependent on the size of the dose, the dosing frequency, the method of administration, and the duration of exposure.
In the antineoplastic treatment, myelosuppression and mucositis are the predominant dose-limiting toxic effects of methotrexate. The severity of these reactions depends on the dose, mode, and duration of application of methotrexate. Mucositis generally appears about 3 to 7 days after methotrexate application, leucopenia and thrombocytopenia follow a few days later. In patients with unimpaired elimination mechanisms, myelosuppression, and mucositis are generally reversible within 14 to 28 days.
Most serious adverse reactions of methotrexate include bone marrow suppression, pulmonary toxicity, hepatotoxicity, renal toxicity, neurotoxicity, thromboembolic events, anaphylactic shock, and Stevens-Johnson syndrome.
Most frequently observed (very common) adverse reactions of methotrexate include gastrointestinal disorders (e.g. stomatitis, dyspepsia, abdominal pain, nausea, loss of appetite) and abnormal liver function tests (e.g. increased Alanine aminotransferase (ALAT), Aspartate aminotransferase (ASAT), bilirubin, alkaline phosphatase). Other frequently occurring (common) adverse reactions are leukopenia, anemia, thrombocytopenia, headache, tiredness, drowsiness, pneumonia, interstitial alveolitis/pneumonitis often associated with eosinophilia, oral ulcers, diarrhea, exanthema, erythema, and pruritus.
The occurrence and severity of adverse reactions depend on dosage level and frequency of administration of methotrexate. However, as severe adverse reactions may occur even at low doses, it is essential for the treating physician to monitor patients closely.
Tabulated list of adverse reactions: The frequencies of the adverse reactions are classified as follows: Very common (≥1/10); common (≥1/100 to <1/10); uncommon (≥1/1000 to <1/100); rare (≥1/10,000 to <1/1,000); very rare (<1/10000), not known (cannot be estimated from the available data). (See Tables 2a and 2b.)


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Immediately notify a doctor or pharmacist of any adverse reactions that may be encountered when using the drug.

Pharmacodynamic interactions: Hepatotoxic agents: Due to its potentially toxic effect on the liver, additional hepatotoxic medicinal products should not be taken during treatment with methotrexate. If concomitant administration cannot be avoided, patients should be monitored closely for signs and symptoms of liver toxicity including closer monitoring of liver enzymes. Consumption of alcohol should be avoided or minimised.
Potentially hepatotoxic agents include e.g. retinoids (e.g. acitretin, etretinate), azathioprine and leflunomide.
Hematotoxic agents: Hematotoxic medicinal products should not be taken during treatment with methotrexate. If concomitant administration cannot be avoided, patients should be monitored closely for signs and symptoms of hematotoxicity including close monitoring of blood count and platelets.
Administration of additional hematotoxic medicinal products (e.g. metamizole) increases the probability of severe hematotoxic effects of methotrexate. Concomitant administration with leflunomide increases the risk for pancytopenia.
In the case of (pre-) treatment with medicinal products, which may have adverse reactions on the bone marrow (e.g. sulfonamides, trimethoprim-sulphamethoxazole, chloramphenicol, pyrimethamine); attention should be paid to the possibility of pronounced impairment of blood formation. Concomitant administration of folate antagonists such as trimethoprim/sulphamethoxazole has been reported to cause acute megaloblastic pancytopenia in rare instances.
Medicinal products that affect folate levels and folic acid-containing vitamin products: The concomitant administration of products that cause folate deficiency (e.g. sulfonamides, trimethoprim sulphamethoxazole) can lead to increased methotrexate toxicity. Particular care is therefore advisable in the presence of existing folic acid deficiency.
The use of nitrous oxide potentiates the effect of methotrexate on folate metabolism, yielding increased toxicity such as severe, unpredictable myelosuppression and stomatitis and in case of intrathecal administration, increased severe, unpredictable neurotoxicity. Whilst this effect can be reduced by administering calcium folinate, the concomitant use of nitrous oxide and methotrexate should be avoided.
Although the combination of methotrexate and sulfasalazine can cause an increase in the efficacy of methotrexate and as a result, more undesirable effects due to the inhibition of folic acid synthesis through sulfasalazine, such undesirable effects have only been observed in rare individual cases in the course of several studies.
Vitamin preparations or other products containing folic acid, folinic acid or their derivatives may decrease the effectiveness of methotrexate.
Ciclosporin: Ciclosporin may potentiate methotrexate efficacy and toxicity. There is a risk of excessive immunosuppression with a risk of lymphoproliferation when the combination is used.
Pharmacokinetic interactions: Interactions that may increase methotrexate levels: Frequent patient monitoring is necessary especially if high methotrexate doses are administered concomitantly with medicinal products, which reduce methotrexate protein binding, eliminate of methotrexate, or cause kidney damage. If concomitant use cannot be avoided, consider dose adjustment of methotrexate. Monitoring of methotrexate serum levels may be useful.
Probenecid, weak organic acids such as loop diuretics, and pyrazoles (phenylbutazone) can reduce the elimination of methotrexate and higher serum concentrations may be assumed to induce higher hematological toxicity.
Methotrexate is plasma protein bound and certain drugs such as oral hypoglycaemics, thiazide diuretics, sulfonamides, phenytoin, barbiturates, tranquilizers, oral contraceptives, amidopyrine derivatives, doxorubicin, p-aminobenzoic acid, some antibiotics such as penicillin, tetracyclines, chloramphenicol decrease this binding, which can lead to increased toxicity when used concurrently.
There is also a possibility of increased toxicity when low-dose methotrexate and non-steroidal anti-inflammatory medicinal products or salicylates are combined. NSAIDs may cause kidney damage.
Concomitant administration of levetiracetam and methotrexate has been reported to decrease methotrexate clearance, resulting in increased/prolonged blood methotrexate concentration to potentially toxic levels. Blood methotrexate and levetiracetam levels should be carefully monitored in patients treated concomitantly with the two drugs.
A concomitant administration of proton-pump inhibitors like omeprazole or pantoprazole can lead to interactions. Concomitant administration of methotrexate and omeprazole has led to delayed renal elimination of methotrexate. In combination with pantoprazole inhibited renal elimination of the metabolite 7-hydroxymethotrexate with myalgia and shivering was reported in one case.
Penicillins, glycopeptides, sulfonamides, ciprofloxacin, and cefalotin can, in individual cases, reduce the renal clearance of methotrexate, so that increased serum concentrations of methotrexate with simultaneous hematological and gastrointestinal toxicity may occur.
The application of procarbazine during high-dose methotrexate therapy increases the risk of impairment of renal function. Delayed methotrexate clearance should also be considered in combination with other cytostatic medicinal products.
Interactions that may reduce methotrexate levels: Concomitant use of enzyme-inducing anticonvulsants (carbamazepine, phenytoin, phenobarbital, primidone) may decrease the methotrexate exposure and impair its therapeutic effect. If used concomitantly, dose adjustment of methotrexate should be considered. Monitoring of methotrexate serum levels may be useful.
Cholestyramine can increase the non-renal elimination of methotrexate by interrupting the enterohepatic circulation. If cholestyramine administration cannot be avoided doses of cholestyramine and methotrexate should be separated as much as possible.
Oral antibiotics like tetracyclines, chloramphenicol, and non-absorbable broad-spectrum antibiotics can interfere with the enterohepatic circulation, by inhibition of the intestinal flora or suppression of the bacterial metabolism.
Methotrexate effects on other medicinal products: Methotrexate increases the plasma levels of mercaptopurine. The combination of methotrexate and mercaptopurine may therefore require dose adjustment.
One should be aware of pharmacokinetic interactions between methotrexate and 5-fluorouracil (increased t½ of 5-fluorouracil). If coadministration is necessary, the patient should be monitored for 5-fluorouracil toxicity and dose adjustments should be considered if necessary.
Theophylline and caffeine: An excessive consumption of caffeine- or theophylline-containing beverages (coffee, caffeine-containing soft drinks, black tea) should be avoided during methotrexate therapy since the efficacy of methotrexate may be reduced due to possible interaction between methotrexate and methylxanthines at adenosine receptors.
Methotrexate may decrease the clearance of theophylline; theophylline levels should be monitored when used concurrently with methotrexate.
Infection risk and vaccinations: Vaccination with a live vaccine in patients receiving chemotherapeutic agents may result in severe and fatal infections. On account of its possible effect on the immune system, methotrexate can falsify vaccinal and test results (immunological procedures to record the immune reaction). During methotrexate therapy, concurrent vaccination with live vaccines must not be carried out.
Particularly in the case of orthopedic surgery where susceptibility to infection is high, a combination of methotrexate with immune-modulating medicinal products must be used with caution.
Radiotherapy: Radiotherapy during use of methotrexate can increase the risk of soft tissue or bone necrosis.

Store below 30°C, protect from light.
Shelf Life: 36 months from manufacturing date.

Immunosuppressants

L04AX03 - methotrexate ; Belongs to the class of other immunosuppressants.