Methotrexate

Should be taken on an empty stomach. Best taken on an empty stomach. May be taken w/ meals to reduce GI discomfort. Avoid taking w/ milk-rich products.

Pre-existing blood dyscrasias (e.g. bone marrow hypoplasia, leucopenia, thrombocytopenia, significant anaemia), active infection, immunodeficiency syndrome (with overt or laboratory evidence), known active gastrointestinal ulcer disease, alcoholism. Severe renal impairment. Significant hepatic impairment (>5 mg/dL bilirubin levels), alcoholic liver disease. Immunisation with live vaccines. Pregnancy and lactation.

Patient with pleural effusion, ascites, folic acid deficiency; inactive and chronic infection (e.g. herpes zoster, TB, hepatitis B or C); risk factors for hepatotoxicity (e.g. persistent abnormal liver chemistries, history of above moderate alcohol consumption, family history of liver disease, diabetes, obesity, hyperlipidaemia), ulcerative colitis. Dehydrated and debilitated patient. Patient undergoing radiotherapy and orthopaedic surgery. Mild to moderate renal impairment. Children and elderly. Patient Counselling This drug may cause fatigue and dizziness, if affected, do not drive or operate machinery. Monitoring Parameters Assess pregnancy status prior to therapy in women of childbearing potential. Oncology: Monitor CBC with differential and platelets, serum creatinine, BUN, LFT at baseline and during therapy; methotrexate levels and urine pH (in high-dose methotrexate); fluid and electrolyte status (in patients with impaired elimination); chest x-ray at baseline; pulmonary function test; signs of toxicities in patients with impaired elimination (e.g. patients with ascites, pleural effusion). Evaluate urinary chorionic gonadotropin (hCG) during initial therapy (in patient with choriocarcinoma). Psoriasis: Monitor CBC with differential and platelets at baseline, 7-14 days after initial therapy or dose increase, every 2-4 weeks for the first few months then every 1-3 months depending on patient condition; BUN and serum creatinine at baseline and every 2-3 months; LFTs at baseline, monthly for 6 months then every 1-2 months; chest x-ray at baseline (patient with underlying disease); pulmonary function test. May consider purified protein derivative skin test for latent TB screening at baseline. Obtain liver biopsy at baseline or after 2-6 months, and with a total cumulative dose of 1.5 g and after each additional 1-5 g in patients with risk factors for hepatotoxicity, or in those without risk factors (with persistent elevations in 5 of 9 AST levels during 12-month period or decreased serum albumin below normal range with normal nutritional status) receiving high doses. Rheumatoid arthritis: CBC with differential and platelets, serum creatinine, LFT at baseline and every 2-4 weeks for 3 months after initial therapy or dose increases, then every 8-12 weeks during 3-6 months of therapy, every 12 weeks beyond 6 months of therapy, thereafter; chest x-ray within 1 year prior to therapy; hepatitis B and C serology (in high-risk patients). Perform TB testing annually for those who live, travel or work in areas with TB exposure. Obtain liver biopsy (in patients with risk factors for hepatotoxicity) at baseline or during treatment if with persistent increase in LFT. Juvenile idiopathic arthritis: Monitor CBC monthly; renal and liver function every 1-2 months; pulmonary function tests (if drug-induced lung disease is suspected).

Significant: Acute renal failure, bone marrow suppression (e.g. anaemia, pancytopenia, neutropenia, leucopenia, thrombocytopenia); gastrointestinal toxicity including ulcerative stomatitis and diarrhea; malignant lymphomas (low dose), impairment of fertility, oligospermia, menstrual dysfunction, pulmonary alveolar haemorrhage; encephalopathy/leucoencephalopathy; radiation recall dermatitis and sunburn; anaphylactic reaction, nonproductive cough, tumour lysis syndrome (in patients with high tumour burden), convulsions (intrathecal). Blood and lymphatic system disorders: Megaloblastic anaemia, haematopoietic disorders, lymphoproliferative disorder, lymphadenopathy. Cardiac disorders: Pericardial effusion. Ear and labyrinth disorders: Tinnitus. Endocrine disorders: Diabetes mellitus. Eye disorders: Conjunctivitis, blurred vision, retinopathy. Gastrointestinal disorders: Dyspepsia, abdominal pain, nausea, vomiting, mucositis, gingivitis, haematemesis, melena, pancreatitis, enteritis, gastrointestinal ulceration and bleeding. General disorders and administration site conditions: Fatigue, lethargy, fever, chills, wound healing impairment, asthenia. Infections and infestations: Respiratory or cutaneous bacterial infections, reactivation of inactive chronic infection. Investigations: Abnormal LFT (e.g. increased AST, ALT, bilirubin, alkaline phosphatase). Metabolism and nutrition disorders: Loss of appetite. Musculoskeletal and connective tissue disorders: Osteoporosis, stress fractures, arthralgia/myalgia, increased rheumatic nodules. Nervous system disorders: Headache, drowsiness, vertigo, paresis, hemiparesis. Psychiatric disorders: Depression, confusion, mood alterations, insomnia, psychoses. Renal and urinary disorders: Ulceration of the bladder, disturbed micturition, oliguria, haematuria, dysuria, anuria, proteinuria, electrolyte disturbance, nephropathy. Reproductive system and breast disorders: Gynecomastia, decreased libido, vaginal bleeding or ulceration, inflammation of the vagina, vaginal discharge. Respiratory, thoracic and mediastinal disorders: Epistaxis. Skin and subcutaneous tissue disorders: Alopecia, photosensitivity, pruritus, acne, ulceration, ecchymosis, erythema, exanthema, herpetiform eruptions of the skin, pigmentary changes, onycholysis, petechiae, hidradenitis, telangiectasia, furunculosis, painful damage to psoriatic lesions, nail hyperpigmentation, acute paronychia. Vascular disorders: Thromboembolic events (e.g. arterial thrombosis, cerebral thrombosis, DVT, retinal thrombosis, thrombophlebitis, pulmonary embolus), vasculitis, hypotension.
Potentially Fatal: Hepatotoxicity (fibrosis, cirrhosis), acute or chronic interstitial pneumonitis often associated with eosinophilia, Pneumocystis jirovecii pneumonia, severe dermatologic reactions (e.g. Stevens-Johnson syndrome, toxic epidermal necrolysis, exfoliative dermatitis, skin necrosis, erythema multiforme).

Increased serum concentration with ciprofloxacin, ciclosporin, penicillin, levetiracetam, probenecid, salicylates, sulfonamides, and PPI (e.g. omeprazole, pantoprazole), phenylbutazone, phenytoin. May enhance adverse effect (particularly pancytopenia) of leflunomide. Concomitant high-dose methotrexate and cisplatin may enhance nephrotoxicity. Reduced intestinal absorption with tetracyclines, non-absorbable broad-spectrum antibiotics, colestyramine. Decreased efficacy with vitamin preparations or other products containing folic acid or its derivatives. Increased risk of marked haematopoietic disorders with trimethoprim-sulfamethoxazole, chloramphenicol, pyrimethamine. Enhanced hepatotoxicity with azathioprine, retinoids and sulfasalazine. May increase plasma levels of mercaptopurine and theophylline. Potentiated effect with nitrous oxide.

Cytotoxic Chemotherapy / Immunosuppressants

L01BA01 - methotrexate ; Belongs to the class of antimetabolites, folic acid analogues. Used in the treatment of cancer.
L04AX03 - methotrexate ; Belongs to the class of other immunosuppressants.