Side Effects of Methotrexate (Anti-Rheumatic) Oral

Methotrexate, an antifolate agent, synthesized in 1948, is a commonly used medicine for certain cancers, and since 1970, after it was realized that it prevents joint deformity and precludes the progression of bony erosion, it is used in the treatment of rheumatoid arthritis. It belongs to the group of drugs called antirheumatics. As Methotrexate interferes with certain cell growth like bone marrow cells, tumor cells, and skin cells, it is also used in the treatment of leukemia, psoriasis, and polyarticular-course juvenile rheumatoid arthritis.

The drug, in low doses as well as high doses, is known to cause numerous side effects.

Common Side Effects

The common side effects include the following:

• Nausea.

• Abdominal pain.

• Fever and chills.

• Fatigue.

• Sensitivity to light.

• Hair loss.

• Mouth sores.

• Burning skin lesions.

• It also produces abnormal values in liver function tests and reduced blood cell counts.

Systemic Side Effects

Methotrexate affects multiple systems, which are manifested by the following symptoms:

1. Renal Failure- Acute renal failure is commonly known. The cause behind this is the tubular necrosis associated with the accumulation of the drug and its metabolites in the tubules, possibly due to their insoluble nature in acidic urine. Alternatively, Methotrexate may be directly toxic to tubules. This may cause a rise in serum Methotrexate levels.

Little or no urination and swelling in the ankles or legs are the signs of renal dysfunction.

2. Neurological Manifestations- Despite the occurrence of acute, subacute, and chronic neuropathy, the mechanisms of neurotoxicity are not well established. Manifestations of acute neuropathy are in the form of aseptic meningitis, leukoencephalopathy affecting the brain and spinal cord, headache, nausea, and vomiting. Subacute neuropathy presents as seizure, paraplegia, or cerebellar dysfunction. Necrotizing leukoencephalopathy is amongst the most common manifestations of chronic neuropathy.

Drowsiness, irritability, problems with coordination, stiffness of the neck, problems in vision, confusion, weakness, loss of body movements, etc., are the associated nervous problems.

3. Hematopoietic Side Effects- Pancytopenia or reduction in any one of the three cell line lineages is frequently seen in the Methotrexate toxicity affecting the hematopoietic system. Megaloblastic anemia, leukopenia (especially neutropenia), thrombocytopenia may all be seen individually or in combinations. An elderly patient with folate deficiency or hypoalbuminemia, dehydration, and renal dysfunction is more predisposed to developing these hematological manifestations. In such cases, even an accidental overdose may lead to pancytopenia.

Lightheadedness, shortness of breath, fatigue, fever, chills, bruises, sores in the skin and mouth, cold extremities, and pale skin are the manifestations of low blood cell count.

4. Hypersensitivity Reactions- Methotrexate, in low as well as high doses, may cause the expression of drug-derived antigens on keratinocytes. These, when detected by cytotoxic-T lymphocytes and mononuclear cells, can result in keratinocyte apoptosis. Hypersensitivity reactions may be considered in both mucocutaneous as well as hematological manifestations.

Ulcers of the oral mucosa and skin, with erythema and urticaria, are frequently seen.

5. Pneumonitis- The patients present with a non-productive cough. This may be associated with fever, dyspnea, or malaise. The patient may be found to have pneumonitis (activated T cells induce a hypersensitivity reaction) or diffuse interstitial disease (lung fibroblasts induced eosinophils, occasionally with peripheral eosinophilia).

6. Hepatic Problems- Abdominal pain is a constant feature of Methotrexate toxicity. This may occasionally be associated with vomiting and diarrhea. Hepatotoxicity, with raised aminotransferase, is frequently seen. Liver damage may be seen with fatty infiltration to fibrosis to frank cirrhosis. Diabetic patients and alcohol users are prone to more severe hepatic involvement.

Right upper abdominal pain, dark-colored urine, yellowish discoloration of skin and whites of the eyes, nausea, loss of appetite, and swelling around the midsection are the signs of liver problems.

7. Tumor Cell Breakdown- The signs of tumor cell breakdown include the following:

• Muscle cramps.

• Fatigue.

• Tingling sensation in the hands, feet, and mouth.

• Nausea.

• Vomiting.

• Increased or decreased heart rate.

• Diarrhea.

8. Fertility Issues- Methotrexate may produce problems with fertility in both men and women.

9. Teratogenic Side Effects of Methotrexate- Methotrexate has abortifacient and teratogenic side effects, and therefore, its use is contraindicated in pregnancy. Also, it is advisable to use effective birth control methods while taking Methotrexate because of its adverse effects on the fetus. It has the following teratogenic side effects:

• Limb defects.

• Craniofacial abnormalities.

• Anencephaly.

• Meningomyelopathy.

• Hydrocephalus.

10. Breastfeeding and Methotrexate- The use of Methotrexate is not recommended in breastfeeding women because it can pass through breast milk. It is advisable to breastfeed the baby only after a week of stopping the medication.

Serious Side Effects

Methotrexate also causes serious side effects which need immediate medical intervention. These include the following:

• Lymph node swelling.

• Loss of weight.

• Vomiting.

• Diarrhea.

• Sudden chest pain.

• Wheezing.

• Dry cough.

• Shortness of breath.

• Cough with mucus or dry cough.

• Difficulty in swallowing.

• Red and warm skin with swelling and oozing.

• Bloody stools.

• Blood in the urine.

• Blister or ulcer formation in the oral cavity.

• Swelling in the gums.

• Night sweats.

Important:

• Alcohol Interaction:Methotrexate, if taken along with alcohol, increases the chance of liver damage.

• Injecting live vaccines is not recommended in people who are taking Methotrexate. MMR (measles, mumps, rubella) vaccine, chickenpox, typhoid, rotavirus, yellow fever, influenza, and shingles vaccine are the live vaccines.

• Methotrexate increases the sensitivity to sunlight and thereby increases the chance of sunburn. So, the use of sunscreen above SPF 30 is advised in people who consume Methotrexate.

Methotrexate Overdose:

Overdose of Methotrexate causes serious complications. Seek immediate help in case of overdosing Methotrexate which shows the following symptoms:

• Nausea and vomiting.

• Bloody stools.

• Unusual bruises.

• Mouth sores.

• Little or no urination.

• Coughing up blood.

• Vomiting blood.

How Should Methotrexate Be Taken?

Methotrexate should not be consumed daily and should be consumed only as per the prescription of the treating doctor. It is usually given weekly, once or two to four times a week. In a few cases, Methotrexate is given daily, followed by a rest period of one week or more. Taking Methotrexate daily without the doctor’s advice may result in the death of the individual.

Conclusion:

Methotrexate should not be consumed without the advice of the doctor. It is also advised to tell the doctor that you are taking Methotrexate before starting any medicine or doing any surgical or dental procedure. Pregnancy planning should be avoided while taking Methotrexate, and also it should not be used in the gestation and postpartum period without the advice of the doctor.