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PubMed1985

Inhibition of dihydrofolate reductase, methotrexate transport, and growth of methotrexate-sensitive and -resistant L1210 leukemia cells in vitro by 5-substituted 2,4-diaminoquinazolines.

A series of eighteen 2,4-diaminoquinazoline analogues of folic, isofolic, pteroic and isopteroic acids having various substituents at position 5 was studied. Each compound was evaluated as an inhibitor of L1210 dihydrofolate reductase, methotrexate influx into L1210 leukemia cells, and growth of methotrexate-sensitive and -resistant L1210 cells in vitro. Bridge reversal at positions 9 and 10 reduced the effectiveness of the classical analogues only with regard to the inhibition of the drug-sensitive cells as compared to methotrexate (MTX). Absence of the glutamate moiety adversely affected the potency of the compounds, particularly when coupled with reversal of the 9,10-bridge. However, the presence of -Cl at position 5 restored significantly the potency of these compounds. The pteroate and isopteroate analogue ethyl esters were generally more effective inhibitors of cell growth than their non-esterified counterparts. Regarding the effects of substituents at position 5, the data suggest that -Cl greater than -CH3 greater than -H for inhibition of methotrexate transport and growth of methotrexate-sensitive L1210 cells. The 5-Cl pteroate analogue and its corresponding ethyl ester were highly effective as growth inhibitors of methotrexate-resistant, transport-defective, L1210 cells in vitro.

Animals↗

PubMed1999

Oral methotrexate compared with injected methotrexate when used with misoprostol for abortion.

OBJECTIVE: This study was undertaken to compare oral to injected methotrexate with respect to effectiveness, side effects, and acceptability. STUDY DESIGN: One hundred women in an urban primary care practice were randomly assigned in phase 1 to receive 50 mg/m(2) methotrexate by either the oral or the injected route. In phase 2 another 87 women were allowed to choose between the oral and injected routes. In both phases and in all groups the methotrexate was followed 5 to 7 days later by misoprostol administered vaginally by the patient. The main outcome was the success rate (the number whose pregnancies aborted without surgery); other outcomes included side effects and acceptability. RESULTS: There were no differences in rates of success, side effects, or acceptability between groups receiving oral and injected methotrexate. Among the women in phase 2 the oral form was chosen by 57.5%. CONCLUSION: This study indicates that for medical abortions induced with methotrexate and misoprostol it is possible to offer both the oral and injected routes of methotrexate without sacrificing efficacy and that about half of the women offered a choice will choose the oral route.

Abortifacient Agents, Nonsteroidal↗

PubMed1995

Combination therapy with cyclosporine and methotrexate in severe rheumatoid arthritis. The Methotrexate-Cyclosporine Combination Study Group.

BACKGROUND: Patients with severe rheumatoid arthritis who are treated with methotrexate frequently have only partial improvement. METHODS: In a six-month randomized, double-blind trial, we compared combination therapy with cyclosporine (2.5 to 5 mg per kilogram of body weight per day in two divided doses at 12-hour intervals) and methotrexate (at the maximal tolerated dose) with methotrexate and placebo in 148 patients with rheumatoid arthritis who had residual inflammation and disability despite partial but substantial responses to prior methotrexate treatment. The primary outcome measure was the change in the number of tender joints. RESULTS: The mean (+/- SD) dose of cyclosporine at the final treatment was 2.97 +/- 1.02 mg per kilogram per day. As compared with the placebo group, the patients in the treatment group had a net improvement in the tender-joint count of 25 percent, or 4.8 joints (95 percent confidence interval, 0.7 to 8.9; P = 0.02), and in the swollen-joint count of 25 percent, or 3.8 joints (95 percent confidence interval, 1.3 to 6.3; P = 0.005); improvement in overall disease activity as assessed by the physician (19 percent, P < 0.001) and the patient (21 percent, P < 0.001); and improvement in joint pain (23 percent, P = 0.04) and in the degree of disability (26 percent, P < 0.001). The mean erythrocyte sedimentation rate increased by 4.2 mm per hour in the cyclosporine group and decreased by 4.8 mm per hour in the placebo group (P = 0.006). Thirty-six patients (48 percent) in the cyclosporine group and 12 patients (16 percent) in the placebo group (P < 0.001) met the 1993 criteria for improvement of the American College of Rheumatology (more than 20 percent improvement in the numbers of both swollen and tender joints and improvement in three of five other variables). Seventeen patients in the cyclosporine group and 12 patients in the placebo group were withdrawn from the study; 2 patients in the cyclosporine group died, 1 from viral pneumonia and the other in a motor vehicle accident. Serum creatinine concentrations increased by a mean of 0.14 +/- 0.27 mg per deciliter (12 +/- 24 mmol per liter) in the cyclosporine group and by 0.05 +/- 0.19 mg per deciliter (4 +/- 17 mmol per liter) in the placebo group (P = 0.02). CONCLUSIONS: In a six-month study, patients with severe rheumatoid arthritis and only partial responses to methotrexate had clinically important improvement after combination therapy with cyclosporine and methotrexate. Side effects were not substantially increased. Long-term follow-up of patients treated with this combination is needed.

Arthritis, Rheumatoid↗

PubMed2002

Cost-effectiveness comparison of therapy for psoriasis with a methotrexate-based regimen versus a rotation regimen of modified cyclosporine and methotrexate.

BACKGROUND: Because health care resources are limited, therapeutic regimens should be assessed for their relative costs and effectiveness. OBJECTIVE: We assessed cost-effectiveness for treating psoriasis using two strategies: one consisted principally of methotrexate and the other was principally a rotational schedule of modified cyclosporine (Neoral) with methotrexate. METHODS: We performed a cost-effectiveness analysis using a computerized decision analytic model of simulated patients with moderate to severe psoriasis. Patients were randomly assigned to receive treatment with one of the two strategies. Direct costs included acquisition of medications, laboratory and physician fees, and costs of treating side effects. Because of uncertainty regarding rates of clearing of psoriasis, the relative efficacy of methotrexate and cyclosporine was varied over a wide range in a sensitivity analysis. RESULTS: In the base case over a 10-year treatment period, the methotrexate strategy cost $33,000 and provided approximately 2 years clear of psoriasis compared with $38,000 and approximately 4 years clear of psoriasis for the rotational strategy. When the relative effectiveness of cyclosporine to methotrexate in clearing psoriasis varied from approximately 1 to 20, the rotational strategy cost from $4100 to $2700 per incremental clear year. CONCLUSION: In selecting therapies for psoriasis patients, both costs and effectiveness should be considered. In this simulation, patients could obtain additional periods clear of psoriasis at an incremental cost by using cyclosporine in rotation with methotrexate. If even a small utility gain accompanies the complete clearing of psoriasis, such a strategy may be a worthwhile investment of resources comparable to other healthcare interventions.

Cost-Benefit Analysis↗

PubMed2006

The molecular mechanism of resistance to methotrexate in mouse methotrexate-resistant cells by cancer drug resistance and metabolism SuperArray.

Drug resistance is often a limiting factor in successful chemotherapy. Understanding of the molecular mechanism of resistance to methotrexate is important for optimal use as well as for the development of new drugs. Using standard cytogenetic techniques, double minutes (DMs) were detected in mouse methotrexate-resistant cell lines inducted in vitro in this study. Moreover, functional SuperArray, determining the regulation of gene expression corresponding to 96 genes involved in the metabolism of and the development of resistance to cancer drugs was used to study in detail the molecular mechanism of resistance to methotrexate. Significant higher expressions of many genes especially dhfr, mrp5, atm and p53 were detected in methotrexate-resistant cells than in normal mouse cells by SuperArray analysis and corresponding excessive expressions of DHFR, MRP5, ATM, and P53 proteins in methotrexate-resistant cells were also confirmed by Western blot analysis. The results in this study indicated that DHFR, MRP5, ATM, and P53 could play important roles in resistance to methotrexate and some of them would be new potential drug targets.

Animals↗

PubMed1997

Risk factors for methotrexate-induced lung injury in patients with rheumatoid arthritis. A multicenter, case-control study. Methotrexate-Lung Study Group.

BACKGROUND: Toxicity limits the use of methotrexate. OBJECTIVE: To identify risk factors for methotrexate-induced lung injury in patients with rheumatoid arthritis. DESIGN: Case-control study. SETTING: One private and five academic rheumatology practices. PARTICIPANTS: Methotrexate recipients with rheumatoid arthritis with and without lung injury. MEASUREMENTS: Potential risk factors examined were sociodemographic and lifestyle characteristics, medical history, clinical and ancillary features and treatment of rheumatoid arthritis before methotrexate therapy, and characteristics of methotrexate therapy. Cases of lung injury were defined according to the modified criteria of Searles and McKendry. RESULTS: Ninety-four percent of the study participants were white, and 67% were women. Case-patients (n = 29) were older than controls (n = 82) (61.5 compared with 54.5 years of age). The strongest predictors of lung injury, after adjustment for other variables, were older age (odds ratio [OR], 5.1 [95% CI, 1.2 to 21.1]), diabetes (OR, 35.6 [CI, 1.3 to infinity]), rheumatoid pleuropulmonary involvement (OR, 7.1 [CI, 1.1 to 45.4]), previous use of disease-modifying antirheumatic drugs (OR, 5.6 [CI, 1.2 to 27.0]), and hypoalbuminemia (OR, 19.5 [CI, 3.5 to 109.7]). Previous use of disease-modifying antirheumatic drugs and hypoalbuminemia had very large attributable risks. CONCLUSION: Knowledge of the risk factors that predispose patients with rheumatoid arthritis to the toxic effects of methotrexate on the lung may provide a rationale for monitoring high-risk patients and may facilitate their management.

Antirheumatic Agents↗

PubMed1989

Immunomodulation by low-dose methotrexate. I. Methotrexate selectively inhibits Lyt-2+ cells in murine acute graft-versus-host reactions.

We have studied the effect of methotrexate in murine acute graft vs host (GvH) disease at concentrations analogous to those used in human rheumatoid arthritis. The GvH reaction was induced by i.v. injection of parental spleen cells into a normal F1 recipient. The acute suppression of T cell function in GvH mice was prevented by methotrexate given orally for 10 days at 1.0 or 0.5 mg/kg but not at 0.25 mg/kg. T cell mitogen response and IL-2 secretion that were inhibited in GvH mice were restored by methotrexate. Protection from immunosuppression in drug-treated GvH mice lasted at least 3 wk after drug dosing was stopped. The mechanism of the protective effect appears to be a preferential inhibition of donor and host Lyt-2+ Ts cell proliferation. In mixing experiments we found that methotrexate inhibited Ts function in GvH mice. By dual fluorescence labeling we showed that the engraftment of donor Lyt-2+ cells was prevented by drug treatment. This was not true of donor L3T4+ cells which were clearly present in the spleens of GvH mice after methotrexate treatment. These donor L3T4 cells were functional in that they induced the production of anti-DNA autoantibodies in the methotrexate-treated GvH mice.

Acute Disease↗

PubMedDate not supplied

A randomized phase III trial of cisplatinum, methotrexate, cisplatinum + methotrexate, and cisplatinum + 5-fluoro-uracil in end-stage head and neck cancer.

In a previous phase III trial of chemotherapy for patients with end-stage squamous cell carcinoma of the head and neck we have shown that Bleomycin shortened the survival period, compared with untreated controls. The survival of patients treated with Cisplatinum and Bleomycin did not differ significantly from untreated patients, but Cisplatinum significantly prolonged survival. A further similar trial is reported here, the four treatment arms were Methotrexate alone, Cisplatinum alone, Cisplatinum + Methotrexate, and Cisplatinum + 5-Fluoro-uracil. The response rates were: Methotrexate alone 19%, Cisplatinum alone 40%, Cisplatinum + Methotrexate 31%, and Cisplatinum + 5-Fluoro-uracil 33%. The median survival time for the Cisplatinum alone group, 260 days, was significantly longer than the 80 days for the Methotrexate alone group. The median survival times for Cisplatinum + Methotrexate (160 days) and for Cisplatinum + 5-Fluoro-uracil (200 days) did not differ significantly from that for Cisplatinum alone.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed1986

Marrow transplantation for severe aplastic anemia: methotrexate alone compared with a combination of methotrexate and cyclosporine for prevention of acute graft-versus-host disease.

Forty-six patients with severe aplastic anemia (median age, 23 years) were treated with high-dose cyclophosphamide followed by infusion of marrow from an HLA-identical family member. To evaluate postgrafting prophylaxis for graft-v-host disease (GVHD), they were entered into a prospective randomized trial comparing the effect of a combination of methotrexate and cyclosporine (n = 22) to that of methotrexate alone (n = 24). Forty-four of the forty-six patients had evidence of sustained marrow engraftment. Only one patient in each of the two study groups showed graft rejection. A significant reduction in the cumulative incidence of grades II to IV acute GVHD was seen in patients given methotrexate/cyclosporine (18%) compared with those given methotrexate alone (53%) (P = .012). In three patients given methotrexate alone, grade III developed, and in six, grade IV acute GVHD developed, compared with none given methotrexate/cyclosporine. Eighteen of the 22 patients given methotrexate/cyclosporine and 15 of the 24 given methotrexate alone are alive between 5.5 and 44.5 months (median, 18 months), with actuarial survival rates at 2 years of 82% and 60%, respectively (P = .062). The incidence of fatal infections was higher in patients given methotrexate alone, whereas there are as yet no significant differences in the incidence of chronic GVHD. We conclude that methotrexate/cyclosporine treatment resulted in a significant decrease in the incidence and severity of acute GVHD in patients who received transplants for severe aplastic anemia and thus an improvement in survival.

Acute Disease↗

PubMed1993

Nonmetastatic gestational trophoblastic disease. Weekly methotrexate compared with 8-day methotrexate-folinic acid.

The efficacy of single agent chemotherapy with methotrexate in low risk gestational trophoblastic disease is well established, but efforts to reduce toxicity and patient time and cost continue. Twenty-five patients with nonmetastatic postmolar gestational trophoblastic disease were seen by the Division of Gynecologic Oncology at the University of South Florida between February 1986 and December 1991. Patients were treated with either weekly intramuscular methotrexate 40 mg/M2 (Group 1, n = 13) or alternating doses of intramuscular methotrexate 1 mg/kg and folinic acid 0.1 mg/kg over eight consecutive days with an eight- day interval (Group 2, n = 12). Patient age, body weight and pre-treatment beta-hCG values were similar in the two groups. One patient defaulted from treatment and was lost to follow-up. All other patients were cured. Complete remission was achieved with primary chemotherapy in nine (69%) patients in Group 1 and nine (75%) in Group 2. All patients with pre-treatment beta-hCG of 650 mIU/ml or less responded to primary therapy whereas 50% of those with higher levels required second-line therapy. When secondary and tertiary treatment were included, the duration of treatment was similar in both groups. Remission was achieved at significantly lower levels of methotrexate in group 1 patients (p < 0.001). No major toxicities occurred. Side effects were gastrointestinal and myelosuppressive and occurred in 2.5% and 15.6% of treatment cycles in Groups 1 and 2, respectively (p < 0.01). Weekly methotrexate is an equally effective and less toxic regimen than eight-day methotrexate-folinic acid in nonmetastatic postmolar gestational trophoblastic disease.

Adult↗

PubMed1985

A randomized prospective comparison of methotrexate with a combination of methotrexate, bleomycin, and cisplatin in head and neck cancer.

Combination chemotherapy with methotrexate, bleomycin, and cis-diamminedichloroplatinum (II) was compared to weekly therapy with methotrexate alone in a randomized prospective trial in 163 patients with recurrent or metastatic squamous cancer of the mucous membranes of the head and neck. The combination produced responses in 48% compared to 35% for methotrexate alone, with 16% complete remissions versus 8%, respectively. The difference in overall and complete remission rates is significant (P = 0.04) using a one-sided binary regression test. Median time to disease progression among responders was 5.8 months for the combination and 5 months for methotrexate, and median survival was 5.6 months in each group. Toxicity was similar in the two groups. Ambulatory patients, those without fixed neck nodes and those without distant metastases, responded more often. Poor performance status, distant metastases, history of heavy smoking, and adjacent organ invasion by the primary tumor were associated with shorter survival, as were weight loss, the presence of tumor in the neck, and heavy alcohol consumption. The addition of bleomycin and cisplatin to methotrexate produces more remissions, and especially complete remissions, but has not made a major impact on the course of far-advanced head and neck cancer.

Adult↗

PubMed2006

Combination treatment with methotrexate, cyclosporine, and intraarticular betamethasone compared with methotrexate and intraarticular betamethasone in early active rheumatoid arthritis: an investigator-initiated, multicenter, randomized, double-blind, parallel-group, placebo-controlled study.

OBJECTIVE: To investigate whether disease control can be achieved in early active rheumatoid arthritis (RA) by treatment with methotrexate and intraarticular betamethasone, and whether the addition of cyclosporine to the regimen has any additional effect. METHODS: Patients (n = 160) were randomized to receive methotrexate 7.5 mg/week plus cyclosporine 2.5 mg/kg of body weight/day (combination therapy) or methotrexate plus placebo-cyclosporine (monotherapy). At weeks 0, 2, 4, 6, and 8 and every 4 weeks thereafter, betamethasone was injected into swollen joints (maximum 4 joints or 4 ml per visit). Beginning at week 8, if synovitis was present, the methotrexate dosage was increased stepwise up to 20 mg/week, with a subsequent stepwise increase in the cyclosporine or placebo-cyclosporine dosage up to 4 mg/kg. RESULTS: At 52 weeks, 20% improvement according to the American College of Rheumatology criteria (ACR20) was achieved in 85% of the combination therapy group versus 68% of the monotherapy group (P = 0.02). The median individual overall ACR response (ACR-N) in the 2 groups was 80.0% (interquartile range 40.1-91.8%) and 54.5% (interquartile range 2.4-87.8%), respectively (P = 0.025). At 48 and 52 weeks, ACR remission criteria were met in 35% of the combination therapy group and 28% of the monotherapy group. Progression in the Larsen score at 52 weeks was -0.2 +/- 6.5 and 0.4 +/- 6.9 (mean +/- SD) in the combination therapy and monotherapy groups, respectively. Serum creatinine levels increased by 7%, and hypertrichosis was more prevalent, in the combination therapy group. CONCLUSION: Combined treatment with methotrexate and intraarticular glucocorticoid showed excellent disease control and stopped the progression of erosions in patients with early active RA, who had a poor prognosis. Addition of cyclosporine improved the ACR20 and ACR-N responses, whereas the ACR50 and ACR70 responses, remission rates, and radiographic changes did not differ between the 2 study groups.

Adult↗

PubMed1990

Comparative study on the pharmacokinetics of 7-hydroxy-methotrexate after administration of methotrexate in the dose range of 0.5-33.6 g/m2 to children with acute lymphoblastic leukemia.

Concentrations of 7-hydroxy-methotrexate (7-OH-MTX) were determined in serum samples obtained after 266 infusions of methotrexate administered to 58 children with acute lymphoblastic leukemia. The dose of methotrexate (MTX) was in the range of 0.5-33.6 g/m2. Pharmacokinetic parameters (metabolic index, drug/metabolite ratio, half-life) of 7-OH-MTX and their relationship to the kinetics of methotrexate were analyzed. A great variability was observed in the extent and time-course of the metabolite formation. The concentration of the metabolite was higher than that of the parent compound at any examined time after the end of the 24 hours' infusion. The increase of 7-OH-MTX levels at the end of the methotrexate infusion was found to be proportionate to the increase of the dose of MTX. Males had significantly higher metabolite levels than did females (P less than 0.01) in the dose range of 0.5-8.0 g/m2. The age of the patients also significantly influenced the rate of the metabolite formation. The serial number of the treatment courses did not have effect on the metabolism of MTX. Dose dependency of the elimination half-life of the metabolite was found. Although a tendency was observed that patients in continuous complete remission had higher metabolite levels than those who relapsed, the difference was not significant. Further studies are needed to determine the clinical importance of 7-OH-MT.

Adolescent↗

PubMed1985

Timing- and sequence-dependent synergism between etoposide and methotrexate or etoposide, methotrexate and 5-fluorouracil in advanced leukemia L1210.

The optimal synergism in combination therapy of leukemia L1210 depends on the sequence and the timing of the agents used. Etoposide (20 mg/kg applied intravenously) 3 h before methotrexate (50 mg/kg administered subcutaneously) results in significantly improved therapeutic action. Simultaneous application of these drugs, or an exceeding of that interval, do not entail synergism. Similar to the results obtained with other transplantable murine tumors, the optimal interval between methotrexate and 5-fluorouracil treatments of leukemia L1210 amounts to 6 h. Sequential treatment with etoposide (20 mg/kg given intravenously) significantly improves the efficacy of combined methotrexate (50 mg/kg applied subcutaneously) and 5-fluorouracil (80 mg/kg administered subcutaneously). The optimal synergism combining etoposide, methotrexate and 5-fluorouracil is achieved when the interval between etoposide and methotrexate amounts to 3 h followed 6 h later by 5-fluorouracil.

Animals↗

PubMed2003

Comparison of intrathecal chemotherapy for leptomeningeal carcinomatosis of a solid tumor: methotrexate alone versus methotrexate in combination with cytosine arabinoside and hydrocortisone.

OBJECTIVE: To compare the efficacy of intrathecal methotrexate single therapy with three-drug combination therapy in patients with leptomeningeal carcinomatosis. METHODS: Fifty-five patients who had pathologically proven leptomeningeal carcinomatosis of a solid tumor were evaluated in terms of pathological response. Group M (n = 29) received methotrexate 15 mg and group MHA (n = 26) received methotrexate 15 mg, hydrocortisone 15 mg/m(2) and ara-C 30 mg/m(2) twice a week intrathecally until a cytological response was obtained. RESULTS: Primary sites of the tumor were the lung (n = 33), breast (n = 13) and stomach (n = 5). The pathology of 45 patients was adenocarcinoma. The cytological response rate to intrathecal chemotherapy was significantly higher in the MHA group than in the M group (38.5 vs 13.8%, P = 0.036). The median survival was 18.6 weeks in the MHA arm and 10.4 weeks in the M arm (P = 0.029). CONCLUSION: Combination intrathecal chemotherapy with methotrexate, cytosine arabinoside and hydrocortisone showed more favorable effects than methotrexate single therapy for leptomeningeal carcinomatosis in solid tumors.

Adenocarcinoma↗

PubMed1995

5'-Cholesteryl-phosphorothioate oligodeoxynucleotides: potent inhibition of methotrexate transport and antagonism of methotrexate toxicity in cells containing the reduced-folate carrier.

Polyanionic 5'-cholesteryl-phosphorothioate oligodeoxynucleotides of varying polymer length and nucleobase composition were examined for an effect on methotrexate transport via the reduced-folate carrier of L1210 mouse cells. Methotrexate transport was inhibited by each of the oligodeoxynucleotide analogs tested. Inhibition was most pronounced (IC50 = 0.21 microM, standard assay) for a 5'-cholesteryl heteropolymer consisting of 15 phosphorothioate deoxynucleotides with alternating deoxycytosine and deoxyadenosine (Chol-PS-d(CA)7C). Homopolymers with 15 deoxycytosine (Chol-PS-dC15) or deoxythymidine (Chol-PS-dT15) residues were approximately 2-fold less inhibitory than Chol-PS-d(CA)7C. The relative potency of transport inhibition by deoxycytosine oligomers of varying length was: Chol-PS-dC5 > Chol-PS-dC15 > Chol-PS-dC28 > Chol-PS-dC3. Substantial inhibition was retained in cells preincubated with inhibitors and washed prior to transport determinations and the inhibitor sensitivity could be increased substantially by reducing the concentration of cells. Mixed competitive and non-competitive inhibition was observed for each analog. In standard high-folate medium, Chol-PS-oligodeoxynucleotides (5.0 microM) had minimal effects on the growth of L1210 cells, but antagonized the cytotoxicity of methotrexate. The response to methotrexate (IC50 = 12 nM) decreased to the greatest extent (20.8-fold) in the presence of Chol-PS-d(CA)7C (IC50 = 250 nM). Under limiting folate conditions, Chol-PS-d(CA)7C alone inhibited cells growth by a process which could be reversed by folic acid. The results show that Chol-PS-oligodeoxynucleotides are among the most potent known inhibitors of the reduced-folate carrier. Direct growth inhibition of folate-deficient cells and antagonism of methotrexate cytotoxicity indicate that Chol-PS-oligodeoxynucleotides retain the ability to inhibit the reduced-folate carrier for several days in cultured cells.

Animals↗

PubMed1985

Changes in liver histology during methotrexate therapy of psoriasis correlated to the concentration of methotrexate and folate in erythrocytes.

To investigate, whether an assessment of the folate and methotrexate concentrations in erythrocytes could be used to indicate incipient histological liver changes, these 2 parameters were related to liver histology in series of liver biopsies (means 4.3 biopsies) from 31 long-term methotrexate-treated psoriasis patients. Logistic regression analysis showed that the probability of changes in liver histology during methotrexate therapy increased significantly with increasing erythrocyte methotrexate concentrations and with decreasing erythrocyte folate concentration. The application of these variables as a decisive criterion when to institute liver biopsy surveillance needs further studies, but can probably help reduce the number of liver biopsies to be taken during long-term methotrexate therapy considerably.

Adult↗

PubMed1978

Radioimmunoassay of methotrexate: use of 75Se-labelled methotrexate.

75Se-labelled methotrexate has been used as the radiolabel in a radioimmunoassay for methotrexate and its use compared with that of 3H-methotrexate. The gamma-labelled drug has proved to be extremely reliable and easier to use than 3H-methotrexate. Results obtained with it compare well with those obtained with tritiated drug. There are practical advantages in using a gamma emitter, and it is suggested that the modified radioimmunoassay is invaluable for routine monitoring of methotrexate in patients undergoing chemotherapy with the drug.

Cross Reactions↗