| 单词 | methotrexate | |||
| 释义 | methotrexateenUKmeth·o·trex·ateM0254800 (mĕth′ə-trĕk′sāt)methotrexate(ˌmɛθəʊˈtrɛkseɪt; ˌmiːθəʊ-)meth•o•trex•ate(ˌmɛθ oʊˈtrɛk seɪt)n.
methotrexateenUKmethotrexate,drug used in halting the growth of actively proliferating tissues. Introduced in the 1950s, it is used in the treatment of leukemialeukemia, cancerous disorder of the blood-forming tissues (bone marrow, lymphatics, liver, spleen) characterized by excessive production of immature or mature leukocytes (white blood cells; see blood) and consequently a crowding-out of red blood cells and platelets. ..... Click the link for more information. , psoriasispsoriasis , occasionally acute but usually chronic and recurrent inflammation of the skin. The exact cause is unknown, but the disease appears to be an inherited, possibly autoimmune disorder that causes the overproduction of skin cells. ..... Click the link for more information. , and non-Hodgkin's lymphomalymphoma, non-Hodgkin's, any cancer of the lymphoid tissue (see lymphatic system) in which the Reed-Sternberg cells characteristic of Hodgkin's disease (the other category of lymphoma) are not present. ..... Click the link for more information. . By binding to an enzymeenzyme, biological catalyst. The term enzyme comes from zymosis, the Greek word for fermentation, a process accomplished by yeast cells and long known to the brewing industry, which occupied the attention of many 19th-century chemists. ..... Click the link for more information. that controls the metabolism of folic acid, methotrexate interferes with synthesis of nucleic acidsnucleic acid, any of a group of organic substances found in the chromosomes of living cells and viruses that play a central role in the storage and replication of hereditary information and in the expression of this information through protein synthesis. ..... Click the link for more information. and therefore with tissue cell reproduction. Because of its immunosuppressive qualities, it is also used in the treatment of rheumatoid arthritisarthritis, painful inflammation of a joint or joints of the body, usually producing heat and redness. There are many kinds of arthritis. In its various forms, arthritis disables more people than any other chronic disorder. ..... Click the link for more information. . methotrexate[‚meth·ə′trek‚sāt]methotrexateenUKmethotrexate[meth″o-trek´sāt]methotrexate (amethopterin, MTX)methotrexate sodiumPharmacologic class: Antimetabolite, folic acid antagonist Therapeutic class: Antineoplastic Pregnancy risk category X FDA Box Warning• Give drug under supervision of physician experienced in antimetabolite use. • Use drug only in life-threatening neoplastic diseases or in patients with severe, recalcitrant, disabling psoriasis that responds inadequately to other therapies. • Deaths have occurred when drug was used to treat cancer and psoriasis. • Monitor patient closely for bone marrow, liver, lung, and kidney toxicities. Explain risks involved, and stress importance of adequate follow-up. • Use caution when giving high-dose regimen for osteosarcoma. (High-dose regimens for other cancers are investigational.) • Don't use preserved forms and diluents containing preservatives for intrathecal or high-dose therapy. • Don't give to pregnant women or women with childbearing potential unless medical evidence suggests benefits may outweigh risks. Drug has caused fetal death and congenital anomalies. • Drug elimination is reduced in patients with renal impairment, ascites, or pleural effusions. Monitor them carefully for toxicity; dosage may need to be reduced or drug may need to be stopped. • Unexpectedly severe (sometimes fatal) bone marrow suppression and GI toxicity have occurred in patients receiving drug (usually in high doses) concurrently with nonsteroidal anti-inflammatory drugs (NSAIDs). • Drug causes hepatotoxicity, fibrosis, and cirrhosis, but generally only after prolonged use. Acute liver enzyme elevations are common but usually transient and asymptomatic. Perform periodic liver biopsies in psoriasis patients receiving long-term therapy. • Potentially dangerous lung disease may arise acutely at any time during therapy. Not always fully reversible, it has occurred at dosages as low as 7.5 mg/week. • Interrupt therapy for diarrhea and ulcerative stomatitis; otherwise, hemorrhagic enteritis and death from intestinal perforation may occur. • Malignant lymphomas may occur at low dosages and may not require cytotoxic treatment. Discontinue drug first; if lymphoma doesn't regress, begin appropriate treatment. • Drug may induce tumor lysis syndrome in patients with rapidly growing tumors. • Severe and occasionally fatal skin reactions have occurred within days of single or multiple P.O., I.M., I.V., or intrathecal doses. Drug withdrawal has led to recovery. • Potentially fatal opportunistic infections may occur. • When given concomitantly with radiation therapy, drug may increase risk of soft-tissue necrosis and osteonecrosis. ActionBinds to dihydrofolate reductase, interfering with folic acid metabolism and inhibiting DNA synthesis and cellular replication AvailabilityInjection: 20-mg, 25-mg, 50-mg, 100-mg, 250-mg, and 1,000-mg vials (lyophilized powder, preservative-free) Tablets: 2.5 mg, 5 mg, 7.5 mg, 10 mg, 15 mg Indications and dosages➣ Acute lymphoblastic leukemia Adults and children: 3.3 mg/m2 P.O. or I.M. daily for 4 to 6 weeks, then 20 to 30 mg/m2 P.O. or I.M. weekly in two divided doses; given with corticosteroid. Alternatively, 2.5 mg/kg I.V. q 14 days. ➣ Meningeal leukemia Adult and children: 12 mg/m2 (maximum of 15 mg) intrathecally at intervals of 2 to 5 days, repeated until cerebrospinal fluid cell count is normal ➣ Burkitt's lymphoma Adults: In stages I and II, 10 to 25 mg P.O. daily for 4 to 8 days; in stage III, combined with other neoplastic drugs. Patients in all stages usually require several courses of therapy, with 7- to 10-day rest periods between courses. ➣ Mycosis fungoides Adults: 2.5 to 10 mg/day P.O. or 50 mg I.M. q week or 25 mg I.M. twice weekly ➣ Osteosarcoma Adults: As part of adjunctive regimen with other antineoplastics, initially 12 g/m2 I.V. as 4-hour infusion, then 12 to 15 g/m2 I.V. in subsequent 4-hour infusions given at weeks 4, 5, 6, 7, 11, 12, 15, 16, 29, 30, 44, and 45 until peak blood level reaches 1,000 micromoles. Leucovorin rescue must start 24 hours after methotrexate infusion begins; if patient can't tolerate oral leucovorin, dose must be given I.M. or I.V. on same schedule. ➣ Trophoblastic tumors (choriocarcinoma, hydatidiform mole) Adults: 15 to 30 mg P.O. or I.M. daily for 5 days. Repeat course three to five times as required, with rest periods of at least 1 week between courses, until toxic symptoms subside. ➣ Lymphosarcoma (stage III) Adults: 0.625 to 2.5 mg/kg/day P.O., I.M., or I.V. ➣ Psoriasis Adults: After test dose, 2.5 mg P.O. at 12-hour intervals for three doses weekly, to a maximum of 30 mg weekly. Alternatively, 10 to 25 mg P.O., I.M., or I.V. as a single weekly dose, to a maximum of 30 mg weekly; decrease dosage when adequate response occurs. ➣ Rheumatoid arthritis Adults: 7.5 mg P.O. weekly as a single dose or divided as 2.5 mg q 12 hours for three doses weekly. May gradually increase, if needed, up to 20 mg/week; decrease when adequate response occurs. Dosage adjustment• Renal or hepatic impairment • Elderly patients Off-label uses• Relapsing-remitting multiple sclerosis • Refractory Crohn's disease Contraindications• Hypersensitivity to drug • Psoriasis or rheumatoid arthritis in pregnant patients • Breastfeeding PrecautionsUse cautiously in: • severe myocardial, hepatic, or renal disease; decreased bone marrow reserve; active infection; hypotension; coma • elderly patients • patients with childbearing potential • young children. AdministrationSee Be aware that methotrexate is a high-alert drug when used orally for nonchemotherapeutic use. See Know that patient must be adequately hydrated before therapy and urine must be alkalized using sodium bicarbonate. • Follow facility policy for handling, preparing, and administering carcinogenic, mutagenic, and teratogenic drugs. • Be aware that oral administration is preferred. Give oral dose 1 hour before or 2 hours after meals. (Food decreases absorption of tablets and reduces peak blood level.) • Reconstitute powder for injection with preservative-free solution, such as 5% dextrose solution or 0.9% sodium chloride injection. Reconstitute 20-mg and 50-mg vials to yield a concentration no greater than 25 mg/ml. Reconstitute 1-g vial with 19.4 ml to yield a concentration of 50 mg/ml. • For high-dose I.V. infusion, dilute in 5% dextrose solution. Administer each 10 mg over 1 minute or by infusion over 30 minutes to 4 hours as directed. • For intrathecal use, reconstitute immediately before administration, using preservative-free solution (such as 0.9% sodium chloride for injection), to a concentration of 1 mg/ml. See For intrathecal or high-dose therapy, use preservative-free injection form. • Avoid I.M. injections if platelet count is below 50,000/mm3. See For osteosarcoma, make sure leucovorin rescue is used appropriately in patients receiving high methotrexate doses. Rescue usually starts 24 hours after methotrexate infusion begins.  Adverse reactionsCNS: malaise, fatigue, drowsiness, dizziness, headache, aphasia, hemiparesis, demyelination, seizures, leukoencephalopathy, chemical arachnoiditis (with intrathecal use) EENT: blurred vision, pharyngitis GI: nausea, vomiting, stomatitis, hematemesis, melena, GI ulcers, enteritis, gingivitis, pharyngitis, anorexia, GI bleeding GU: hematuria, cystitis, infertility, menstrual dysfunction, defective spermatogenesis, abortion, tubular necrosis, severe nephropathy, renal failure Hematologic: anemia, leukopenia, thrombocytopenia, severe bone marrow depression Hepatic: hepatotoxicity Metabolic: hyperuricemia, diabetes mellitus Musculoskeletal: joint pain, myalgia, osteonecrosis, osteoporosis (with long-term use in children) Respiratory: dry nonproductive cough, pneumonitis, pulmonary fibrosis, pulmonary interstitial infiltrates Skin: pruritus, rash, urticaria, alopecia, painful plaque erosions, photosensitivity Other: chills, fever, increased susceptibility to infection, septicemia, anaphylaxis, sudden death InteractionsDrug-drug. Activated charcoal: decreased blood level of oral or I.V. methotrexate Folic acid derivatives: antagonism of methotrexate effects Fosphenytoin, phenytoin: decreased blood levels of these drugs Hepatotoxic drugs: increased risk of hepatotoxicity NSAIDs, phenylbutazone, probenecid, salicylates, sulfonamides: increased methotrexate toxicity Oral antibiotics: decreased methotrexate absorption Penicillin, sulfonamide: increased methotrexate blood level Procarbazine: increased nephrotoxicity Theophylline: increased theophylline level Vaccines: vaccine inefficacy Drug-diagnostic tests. Hemoglobin, platelets, red blood cells, white blood cells: decreased values Pregnancy tests: false-positive result Protein-bound iodine, transaminases, uric acid: increased levels Drug-food. Any food: delayed methotrexate absorption and decreased peak blood level Drug-herbs. Astragalus, echinacea, melatonin: interference with methotrexate-induced immunosuppression Drug-behaviors. Alcohol use: increased hepatotoxicity Sun exposure: photosensitivity Patient monitoring• Watch for vomiting, diarrhea, or stomatitis, which may cause dehydration. See Know that high-dose therapy may cause nephrotoxicity. Monitor renal function, hydration status, urine alkalization (for pH above 6.5), and methotrexate blood level. See Assess for fever, sore throat, bleeding, increased bruising, and other signs and symptoms of hematologic compromise or infection. • With high-dose or intrathecal therapy, watch for CNS toxicity. See Monitor creatinine and methotrexate blood levels 24 hours after therapy starts and then daily. Adjust leucovorin dosage as prescribed. • Check hematologic studies at least monthly; blood or platelet transfusions may be necessary. • Monitor liver and kidney function studies every 1 to 3 months. Evaluate uric acid levels. See Watch for signs and symptoms of pulmonary toxicity, such as fever, dry nonproductive cough, dyspnea, hypoxemia, and infiltrates on chest X-ray. • Know that methotrexate exits slowly from third-space compartments (ascites, pleural effusions). Before therapy starts, fluid should be evacuated; during therapy, monitor drug blood level. Patient teachingSee Review dosing instructions carefully with patient to avoid toxicity. Tell patient with rheumatoid arthritis or psoriasis to take doses weekly. • Advise patient to take oral doses 1 hour before or 2 hours after meals. • Instruct patient to report diarrhea, abdominal pain, clay-colored or black tarry stools, fever, chills, sore throat, unusual bleeding or bruising, sores in or around mouth, cough or shortness of breath, yellowing of skin or eyes, dark or bloody urine, swelling of feet or legs, or joint pain. • Tell patient to take temperature daily and to report fever or other signs or symptoms of infection. • Instruct patient to drink 2 to 3 L of fluid each day. • Advise male patients to use reliable contraception during and for at least 3 months after therapy. Advise female patients to use reliable contraception during and for one ovulatory cycle after therapy; also caution them not to breastfeed. • Advise patient to avoid sun exposure and to use sunscreen and protective clothing (especially if he has psoriasis). • Instruct patient to avoid alcohol. • Tell patient he'll need to undergo blood tests during therapy. • As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs, tests, foods, herbs, and behaviors mentioned above. meth·o·trex·ate(meth'ō-trek'sāt),methotrexate(mĕth′ə-trĕk′sāt)methotrexateA widely used, toxic antimetabolic agent. MTX is a potent folic acid antagonist (antifolate) and competes with dihydrofolate (the natural substrate) for binding sites on dihydrofolate reductase (DHFR), blocking production of tetrahydrofolate; folate is the vitamin co-factor in methyl group transport for purine and thymidilic acid synthesis and DNA synthesis.Toxicity Nausea, vomiting, anorexia, stomatitis, CNS changes, hypersensitivity, liver damage, ocular irritation, dose-limiting myelotoxicity may appear 4–7 days after beginning therapy, nephrotoxicity (crystallisation within renal tubules). Lab Transient increase of LFTs. Gynaecology—Indications May be used to manage tubal pregnancy; evokes resorption or tubal abortion by an unknown mechanism; failure of MTX is increased if hCG levels are increased. Pronunciation Medspeak-UK: pronounced MEE tho trex ate Medspeak-US: pronounced MEH tho trex ate Oncology A widely used chemotherapeutic, which may be used alone to cure certain malignancies (e.g., choriocarcinoma) or with other agents for lymphoproliferations (ALL; ANLL; Hodgkin lymphoma; non-Hodgkin’s, Burkitt’s and histiocytic lymphomas; mycosis fungoides; myeloma; head and neck, ovarian and small-cell carcinomas; osteosarcoma; medulloblastoma) and nonmalignant conditions (e.g., recalcitrant psoriasis, rheumatoid arthritis, inflammatory bowel disease). Combined with cyclosporine and prednisone, MTX reduces the incidence of acute GVHD from 23% to 9%, without affecting disease-free survival. methotrexateFolex® PFS, Rheumatrex® Oncology A widely used but toxic antimetabolic chemotherapeutic which may be used alone to treat certain malignancies–eg, choriocarcinoma, and with other agents for lymphoproliferations–ALL, ANLL, Hodgkin's disease, non-Hodgkin's, Burkitt's and histiocytic lymphomas, mycosis fungoides, myeloma, head & neck, ovarian and small cell carcinomas, osteosarcoma, medulloblastoma; nonmalignant conditions–eg, recalcitrant psoriasis, rheumatoid arthritis; combined with cyclosporine and prednisone, MTX ↓ the incidence of acute GVHD from 23% to 9%, without affecting disease-free survival; MTX is a potent folic acid antagonist–antifolate and competes with dihydrofolate—the natural substrate, for binding sites on dihydrofolate reductase–DHFR, blocking production of tetrahydrofolate–folate is the vitamin co-factor in methyl group transport for purine and thymidilic acid synthesis and DNA synthesis. See Leucovorin rescue, MDR gene Toxicity N&V, anorexia, stomatitis, CNS changes, hypersensitivity, liver damage, ocular irritation, dose-limiting myelotoxicity may appear 4-7 days after beginning therapy, nephrotoxicity–crystallization within renal tubules Lab Transient ↑of LFTs.meth·o·trex·ate(meth'ō-trek'sāt)methotrexateAn ANTIMETABOLITE and IMMUNOSUPPRESSIVE drug used to treat cancer and help in the treatment of RHEUMATOID ARTHRITIS. It acts by interfering with the metabolism of FOLIC ACID. The drug is on the WHO official list. A brand name is Maxtrex.Methotrexateimmunosuppressantsmeth·o·trex·ate(meth'ō-trek'sāt)Patient discussion about methotrexateQ. Is methotrexate available in the United States as a treatment for fibromyalgia? Last year I was diagnosed as fibromyalgia. I feel a lot of fatigue and stiffness. I came upon a website from where I read that rheumatoid arthritis causes those same symptoms and can be treated with methotrexate. After reading that, I purchased a half year supply of the drug over the counter in Mexico. It eliminated all of my symptoms. A month after my supply ran out, all the symptoms returned. Is methotrexate available in the United States as a treatment for fibromyalgia? methotrexateenUK
Synonyms for methotrexate
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