Uses of Trexall Tablet: - Rheumatoid arthritis - Psoriasis Burkitt's lymphoma, Choriocarcinoma, Mycosis fungoides, Crohn's disease, Psoriasis, Osteosarcoma, Breast cancer, lymphosarcoma, Acute lymphoblastic leukaemia, Rheumatoid arthritis Severe renal or hepatic impairment, pre-existing profound bone marrow suppression in patients with psoriasis or rheumatoid arthritis, alcoholic liver disease, AIDS, pre-existing blood dyscrasias, pregnancy (in patients with psoriasis or rheumatoid arthritis), breast-feeding.

Antidote preparations, Immunosuppressant

Methotrexate inhibits dihydrofolic acid reductase. Dihydrofolates must be reduced to tetrahydrofolates by this enzyme before they can be utilized as carriers of one-carbon groups in the synthesis of p.r.n. nucleotides and thymidylate. Therefore, methotrexate interferes with DNA synthesis, repair, and cellular replication. Actively proliferating tissues such as malignant cells, bone marrow, fetal cells, buccal and intestinal mucosa, and cells of the urinary bladder are in general more sensitive to this effect of methotrexate. When cellular proliferation in malignant tissues is greater than in most normal tissues, methotrexate may impair malignant growth without irreversible damage to normal tissues

How to use Methotrexate: Take this medicine in the dose and duration as advised by your doctor. Swallow it as a whole. Do not chew, crush or break it. Methotrexate may be taken with or without food, but it is better to take it at a fixed time. Administration: 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. IV/IM Preparation Reconstitute with D5W or NS: 20-mg vial, up to 25 mg/mL; 1-g vial, up to 50 mg/mL May dilute further for IV infusion IV/IM Administration Administer by IM, IV push, or IV infusion Regular IV given with no more than 25 mg/mL IV push: Administered at 10 mg/min IV infusion (usually >100 mg): Administered over 30 minutes to 4 hours, or according to institutional protocol High-dose therapy (uses 1-g vial): Administered over 4 hours Specific dosing schemes vary, but high doses should be followed by leucovorin 24 hours after initiation of therapy to prevent toxicity Adult Dose: Adult: PO Burkitt's lymphoma 10-25 mg/day for 4-8 days, repeat after 7-10 days. Choriocarcinoma 15-30 mg/day for 5 days, repeat after an interval of at least 1 wk for 3-5 courses. Mycosis fungoides 2.5-10 mg/day to induce remission. Rheumatoid arthritis 7.5 mg once wkly, adjust if needed. Up to 20 mg/wk. Crohn's disease 12.5-22.5 mg once wkly for up to 1 yr. PO/IV/IM Psoriasis 10-25 mg once wkly, adjust subsequent doses if needed. IV Osteosarcoma 12-15 g/m2 as infusion, followed by folinic acid. Breast cancer 10-60 mg/m2 often w/ cyclophosphamide and fluorouracil. Advanced lymphosarcoma Up to 30 mg/kg, followed by folinic acid rescue. Acute lymphoblastic leukaemia Maintenance: 2.5 mg/kg every 14 days. PO/IM Acute lymphoblastic leukaemia Maintenance: 15 mg/m2 1-2 times/wk w/ other agents. IM Choriocarcinoma 15-30 mg/day for 5 days. Repeat after at least 1 wk for 3-5 courses. Mycosis fungoides 50 mg/wk in 1-2 divided doses. Crohn's disease 25 mg once wkly for 16 wk. Maintenance: 15 mg/wk. Intrathecal Meningeal leukaemia 12 mg/m2 (Max: 15 mg) once wkly for 2-3 wk, then once mthly. Hepatic impairment Bilirubin 3.1-5.0 mg/dL or AST > 3 times ULN: Give 75% of dose Bilirubin >5.0 mg/dL: Avoid use Child Dose: Polyarticular Juvenile Idiopathic Arthritis Initial: 10 mg/m² PO/IM/SC qWeek Meningeal Leukemia <1 year: 6 mg intrathecally (IT) every 2-5 days 1-2 years: 8 mg IT every 2-5 days 2-3 years: 10 mg IT every 2-5 days >3 years: 12 mg IT every 2-5 days Renal Dose: Renal impairment: CrCl (ml/min) Dosage Recommendation 61-80 75% of dose 51-60 70% of dose 10-50 30-50% of dose <10 Avoid use Intermittent hemodialysis: 50% of dose at normal dosing interval Continuous renal replacement therapy: 50% of dose at normal dosing interval

Decreased effectiveness with folic acid and its derivatives. Potentially Fatal: Increased toxicity with NSAIDs and salicylates; probenecid; some penicillins; aminoglycosides neomycin and paromomycin; sulfonamides such as sulfafurazole and sulfamethoxazole; co-trimoxazole or trimethoprim; nephrotoxic agents (e.g. cisplatin); ciclosporin; etretinate. Synergistic enhancement of effects with fluorouracil. Increased bioavailability of mercaptopurine. Reduces serum-valproate concentrations. Reduced serum concentrations with colestyramine. Increased serum concentrations with omeprazole.

Severe renal or hepatic impairment, pre-existing profound bone marrow suppression in patients with psoriasis or rheumatoid arthritis, alcoholic liver disease, AIDS, pre-existing blood dyscrasias, pregnancy (in patients with psoriasis or rheumatoid arthritis), breast-feeding.

Common - Abdominal pain - Indigestion - Loss of appetite - Nausea - Vomiting - Tiredness - Mouth sore >10% Arachnoiditis with intrathecal administration,Subacute toxicity with intrathecal administration (paralysis of extremities, cranial nerve palsy, seizure or coma),Demyelinating encephalopathy with cranial irradiation or other systemic chemotherapy,Reddening of skin,Hyperuricemia,Ulcerative stomatitis,Glossitis,Gingivitis,Nausea and vomiting,Diarrhea,Anorexia,Intestinal perforation,Mucositis (dose-dependent),Leukopenia,Thrombocytopenia,Renal failure,Azotemia,Nephropathy,Pharyngitis 1-10% Alopecia,Photosensitivity,Rash,Abdominal distress,Malaise,Fatigue,Chills, fever,Decreased resistance to infection,Gastrointestinal hemorrhage,Myelosuppression,Disorders of lung, interstitial pneumonia (acute, chronic),Atrophy of liver, cirrhosis, hepatic fibrosis or necrosis, elevated liver function tests, hepatic failure Potentially Fatal: Pulmonary reactions (e.g. interstitial lung disease); neurotoxicity (e.g. leukoencephalopathy, paresis, demyelination) with intrathecal use; foetal deaths.

Pregnancy category X. Studies in animals or human beings have demonstrated fetal abnormalities or there is evidence of fetal risk based on human experience or both, and the risk of the use of the drug in pregnant women clearly outweighs any possible benefit. The drug is contraindicated in women who are or may become pregnant.

Precaution: Hepatic or renal impairment, bone marrow depression, elderly, neonates. Ulcerative disorders of the GI tract. Monitor haematological, renal and hepatic function, and GI toxicity regularly. Lactation: Drug excreted in breast milk; do not nurse

Leucovorin is indicated to diminish the toxicity and counteract the effect of inadvertently administered overdosages of methotrexate and its administration should begin as promptly as possible.

Store at a temperature not exceeding 30°C in a dry place. Protect from light & moisture.

Antidote preparations, Immunosuppressant

Methotrexate is a folic acid antagonist that inhibits DNA synthesis. It irreversibly binds to dihydrofolate reductase, inhibiting the formation of reduced folates, and thymidylate synthetase, resulting in inhibition of purine and thymidylic acid synthesis.

US FDA Pregnancy Category X. Methotrexate should be used in the treatment of neoplastic diseases only when the potential benefit outweighs the risk to the fetus. It is contraindicated in nursing mothers.