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PubMed1980

Limited penetration of methotrexate into human osteosarcoma spheroids as a proposed model for solid tumor resistance to adjuvant chemotherapy.

It is generally accepted that oxygen has a limited ability to diffuse into solid tumor masses. However, the question of the ability of chemotherapy agents to penetrate solid tumor masses has not been evaluated. This clearly would have an impact on the ability of chemotherapy to control microscopic disease during the "avascular" phase of growth. An attempt was made to evaluate the ability of methotrexate to penetrate solid tumor masses when grown in three dimensions (spheroids). Since methotrexate is used in the clinical management of human osteosarcoma, we chose this drug-tumor combination for our studies. This was done by growing human osteosarcoma cells into spheroids and exposing spheroids of various sizes to tritiated methotrexate. Audioradiographs were obtained from sections through the center of spheroids of various sizes. Our findings suggest that methotrexate has a limited ability to penetrate into avascular tumor masses when grown in three dimensions. This is most evident when the tumor masses are approximately 250 micron and larger in diameter. In addition, we compared the degree of penetration of methotrexate to the growth fraction of the tumor, as measured by tritiated thymidine, and found that the growth fraction was much greater than the fraction of cells reached by methotrexate. We conclude that the limited ability of methotrexate to penetrate solid tumor masses offers an alternative explanation for the limited effectiveness of methotrexate when used as an adjuvant for osteosarcoma. We question whether the established biochemical mechanisms for methotrexate resistance are comprehensive explanations for its limited clinical effectiveness.

Autoradiography↗

PubMed1995

Attenuation of interleukin 2-induced pulmonary vascular leak syndrome by low doses of oral methotrexate.

Pulmonary vascular leak induced in mice by interleukin 2 (IL-2) was attenuated by pretreatment with single or multiple doses of oral methotrexate. Methotrexate also attenuated pulmonary vascular leak when either larger doses of IL-2 or when lymphokine-activated killer (LAK) cells or LAK cells plus IL-2 were administered. Lymphoid infiltrates in the lungs of mice treated with IL-2 and methotrexate were significantly lower. The number of mice surviving treatment with high doses of IL-2 was also significantly increased when these mice were treated with methotrexate. Methotrexate prevented the IL-2-induced increase in the number of splenocytes that were asialo GM1+ but had no effect on Lyt 2+ or L3T4+ cell content. A marginal but significant inhibition in the generation of effector splenocytes that were cytolytic to either YAC or MCA-205 tumor targets was observed in mice treated with methotrexate and IL-2. In vivo studies indicated that methotrexate did not compromise the anti-tumor efficacy of treatment regimens that contained IL-2, LAK cells, or IL-2 and LAK cells. These results demonstrate the potential clinical utility of methotrexate in attenuating pulmonary vascular leak induced by IL-2 without compromising its efficacy. One potential mechanism of action of methotrexate is related to its ability to stimulate the release of adenosine followed by the inhibition of the adhesion of leukocytes to the IL-2-activated endothelium.

2-Chloroadenosine↗

PubMedDate not supplied

Methotrexate as rescue/adjunctive immunotherapy in infant and adult heart transplantation.

Methotrexate may be a useful adjunct to more conventional immunosuppression in heart transplantation, but experience is limited. We report our findings in 18 patients aged 19 days to 64 years, who were treated with methotrexate. Five patients were less than 1 year of age; 11 patients were over 16 years of age. Indications could be divided in two groups. Seven patients were treated with methotrexate as rescue therapy for unresolving acute grade 3 rejection or for early recurrence after one rejection episode that had been treated with steroids and antilymphocyte serum. All infants were treated with methotrexate for life-threatening rejection. Methotrexate was given as an adjunct to conventional treatment in six patients for mild rejection, which occurred while steroids were being decreased or in patients with relative contraindications to high-dose steroids. One grade 3b rejection could not be reversed with methotrexate and led to the patient's death 3 months later. One grade 1b rejection only temporarily improved and was actually reversed with high-dose steroids after 4 months. All other rejections were rapidly reversed with the use of methotrexate. Tolerance of methotrexate has been very good with transient leukopenia in four patients, with ulcerative stomatitis in one patient, and with transient elevation of liver enzymes in two patients. We conclude that methotrexate is a valuable rescue/adjunctive immunotherapeutic agent that is capable of altering heart rejection with considerable safety and efficacy.

Adolescent↗

PubMed2000

Methotrexate as a steroid sparing agent for asthma in adults.

BACKGROUND: Sustained oral corticosteroid use can lead to complications, so there is interest in identifying agents that can reduce oral steroid use in people with asthma. Methotrexate has attracted attention as a possible steroid sparing agent in patients with chronic oral steroid dependent asthma. OBJECTIVES: The objective of this review was to assess the effects of adding methotrexate to oral corticosteroids in adults with stable asthma who are dependent on oral corticosteroids. SEARCH STRATEGY: The Cochrane Airways Group trials register and reference lists of identified articles were searched. SELECTION CRITERIA: Randomised trials of the addition of methotrexate compared with placebo in adult steroid dependent asthmatics. Duration of therapy needed to be at least 12 weeks. DATA COLLECTION AND ANALYSIS: Trial quality was assessed and data extraction was carried out by two reviewers independently. Study authors were contacted for missing information. MAIN RESULTS: Ten trials involving a total of 185 people were included. Study design and quality, corticosteroid dosages and outcomes varied widely. There was a reduction in oral corticosteroid dose favouring methotrexate in parallel trials (weighted mean difference -4.1 mg per day, 95% confidence interval -6.8 to -1.3) and also in cross-over trials (weighted mean difference -2.9 mg per day, 95% confidence interval -5.9 to -0.2). There was no difference between methotrexate and placebo for forced expiratory volume in one minute (weighted mean difference 0.12 litre, 95% confidence interval -0.21 to 0.45). Hepatotoxicity was a common adverse effect with methotrexate compared to placebo (odds ratio 6.9, 95% confidence interval 3.1 to 15.5). REVIEWER'S CONCLUSIONS: Methotrexate may have a small steroid sparing effect in adults with asthma who are dependent on oral corticosteroids. However, the overall reduction in daily steroid use is probably not large enough to reduce steroid-induced adverse effects. This small potential to reduce the impact of steroid side-effects is probably insufficient to offset the adverse effects of methotrexate.

Administration, Oral↗

PubMed2003

Methotrexate for induction of remission in refractory Crohn's disease.

BACKGROUND: Although corticosteroids are effective for induction of remission of Crohn's disease, approximately 20% of patients who respond relapse when steroids are withdrawn and become steroid dependent (Binder 1985). Furthermore, corticosteroids exhibit significant adverse effects. The success of methotrexate as a treatment for rheumatoid arthritis led to its evaluation in patients with refractory Crohn's disease. Methotrexate has been studied for induction of remission of refractory Crohn's disease and has become the principal alternative to azathioprine/6MP therapy. The evidence for its effectiveness has not been subjected to a systematic review. OBJECTIVES: To conduct a systematic review of the evidence for effectiveness of methotrexate for induction of remission in patients with active Crohn's disease in the presence and absence of concomitant steroid therapy. SEARCH STRATEGY: A computer-assisted search of MEDLINE and EMBASE for relevant studies published in English, French, Spanish, Italian and German between 1966 and June 2002. Manual searches of reference lists from potentially relevant papers were performed to identify additional studies. The Cochrane Controlled Trials Register and the IBD Review Group Specialized Trials Register were also searched. SELECTION CRITERIA: Randomized controlled trials involving patients of age > 17 years with refractory Crohn's disease defined by conventional clinical, radiological and endoscopic criteria, which was categorized as being active (Crohn's disease activity index >150). DATA COLLECTION AND ANALYSIS OUTCOME MEASURES: The outcome measure was the rate of induction of remission and complete withdrawal from steroids in the treatment and control groups after 16 weeks of treatment. A secondary outcome was induction of remission with reduction in steroid dose of at least 50%. Selection of trials: The results of the searches above were reviewed independently by two observers and relevant studies selected according to the predefined selection criteria. Any disagreement among reviewers was resolved by consensus. The same two reviewers assessed the methodological quality of each trial (details of randomization method, including whether intention-to-treat analysis was possible from the published data, number of patients lost to follow-up, and if a blinded outcome assessment was used). A standard data extraction form was used. Appropriateness of combining results: Trials were first reviewed to assess the clinical comparability of trial protocols and study populations. MAIN RESULTS: Three randomized placebo-controlled trials were identified. The three studies differed with respect to participants, intervention, and outcomes to the extent that it was considered to be inappropriate to combine the data statistically. Two studies which employed low doses of methotrexate orally showed no statistically significant difference between methotrexate and placebo treated patients, and one which employed a higher dose intramuscularly showed substantial benefit (number needed to treat, NNT=5). Adverse effects were more common with high dose intramuscular methotrexate therapy than with placebo. REVIEWER'S CONCLUSIONS: There is evidence from a single large randomized trial on which to recommend the use of methotrexate 25 mg intramuscularly weekly for induction of remission and complete withdrawal from steroids in patients with refractory Crohn's disease. Although adverse effects are more common than with placebo, they were not severe. There is no evidence on which to base a recommendation for use of lower dose oral methotrexate.

Crohn Disease↗

PubMed2003

Etanercept added to background methotrexate therapy in patients with rheumatoid arthritis: continued observations.

OBJECTIVE: To observe the long-term safety and efficacy of combination therapy with etanercept and methotrexate in patients with rheumatoid arthritis (RA), and to determine whether the addition of etanercept allowed reductions in methotrexate or corticosteroid dosages while maintaining a clinical response. METHODS: Patients with RA who received methotrexate plus etanercept in a previous randomized, placebo-controlled trial were offered the opportunity to enroll in an open-label extension study for further evaluation of treatment with etanercept and methotrexate. RESULTS: Seventy-nine of the 89 patients in the original blinded study enrolled in the extension study, and 65 of these patients continue in the study. Patients have received etanercept therapy for up to 47 months (median 44 months). The types and rate of adverse events noted during the extension trial were similar to those observed in the controlled trial. At the 3-year assessment, 77% of the 57 patients available for evaluation met American College of Rheumatology 20% (ACR20) criteria for improvement in RA, 47% met the ACR50 criteria, and 23% met the ACR70 criteria. Of the 36 patients assessed at 3 years in the extension study, 30 (83%) were able to decrease their dosages of corticosteroids, and 20 (56%) were able to discontinue corticosteroid therapy. At 3 years, the dosage of methotrexate was decreased in 41 of 66 patients (62%), and methotrexate therapy was discontinued in 19 patients (29%). CONCLUSION: In this observational continuation study, the addition of etanercept to background methotrexate provided sustained clinical benefit over a median period of 44 months. With etanercept therapy, there were trends toward dosage reduction or discontinuation of methotrexate and corticosteroids, without apparent worsening of ACR response rates. Compared with the controlled trial, no increases in the rate of adverse events were observed.

Adult↗

PubMed2004

Reduction of synovial sublining layer inflammation and proinflammatory cytokine expression in psoriatic arthritis treated with methotrexate.

OBJECTIVE: Methotrexate is one of the most commonly used disease-modifying antirheumatic drugs in the management of psoriatic arthritis (PsA). Despite the differences between the inflammation in PsA and rheumatoid arthritis (RA), the effects of methotrexate on the synovium have been described solely in RA. In this study, we sought to determine the effects of methotrexate on the inflammatory infiltrate and on cytokine and metalloproteinase gene expression in the synovium of PsA patients. METHODS: Ten patients with PsA (median duration 18 months) underwent arthroscopy and synovial biopsy of an inflamed knee before and after clinical improvement induced by methotrexate. Immunohistologic analysis was performed using antibodies to CD3, CD4, CD8, CD68, factor VIII, vascular cell adhesion molecule, E-selectin, and intercellular adhesion molecule (ICAM). Matrix metalloproteinase 3 (MMP-3) and tissue inhibitor of metalloproteinases 1 (TIMP-1) messenger RNA (mRNA) were quantified by competitive reverse transcription-polymerase chain reaction (RT-PCR). Interleukin-1alpha (IL-1alpha), IL-1beta, IL-2, IL-4, IL-5, IL-8, IL-10, IL-12p35, IL-12p40, IL-15, interferon-gamma (IFNgamma), and tumor necrosis factor alpha (TNFalpha) mRNA expression was quantified by real-time PCR. RESULTS: Patients received a median methotrexate dosage of 13.75 mg/week (range 7.5-15) for a median of 11.5 months (range 7-14 months). The Ritchie Articular Index, swollen joint count, and Disease Activity Score were significantly reduced. There was a decrease in all immunohistologic staining, although this was statistically significant only for CD3, CD4, CD8, CD68, E-selectin, and ICAM. Despite clinical improvement in all patients, there was a residual T cell infiltrate in all synovial biopsy tissues. The synovial lining layer thickness, but not hypervascularity, was significantly reduced. There was also a significant reduction in MMP-3, but not TIMP-1, expression. Before treatment, PsA synovium was characterized by a predominant expression of the proinflammatory cytokines IL-15, IFNgamma, IL-1beta, and TNFalpha and the antiinflammatory cytokine IL-10. Methotrexate reduced synovial IL-1alpha, IL-1beta, IL-8, IL-10, IL-15, IFNgamma, and TNFalpha mRNA expression, but the effect was significant only for IL-8. CONCLUSION: Methotrexate produced a clinical response in PsA by reducing, but not abolishing, the inflammatory infiltrate, adhesion molecule expression, and MMP-3 and proinflammatory cytokine gene expression, particularly IL-8, in the synovium. Methotrexate did not reduce hypervascularity, which is a prominent differentiating feature of PsA synovium.

Antirheumatic Agents↗

PubMed2002

Transport of methotrexate into LNCaP human prostate cancer cells.

Uptake of methotrexate into the LNCaP human prostate cancer cells was linear for the first 60 min. The initial rate of methotrexate uptake was highest at extracellular pH 4.5 and decreased markedly until pH 7.0 to 8.0. Transport of methotrexate into LNCaP cells showed two components, one saturable -K(m) = 0.13 +/- 0.06 microM and V(max) = 1.20 +/- 0.16 pmol x 45 min(-1) x mg(-1) protein at low concentrations and the other apparently not saturable up to 10 microM. Uptake of methotrexate was inhibited by structural analogs with the K(i) values being 6.53, 12.4, and 85.6 microM for 5-formyltetrahydrofolate, 5-methyltetrahydrofolate, and folic acid, respectively. Uptake of methotrexate into LNCaP cells was not inhibited by the energy poisons in contrast to methotrexate uptake into PC-3 prostate cancer cells. Uptake was inhibited by increasing concentrations of sulfate and phosphate ions and by the organic anions probenecid and DIDS, suggesting that methotrexate may be transported by an anion-exchange mechanism. These results show that methotrexate is transported into LNCaP prostate cancer cells by a carrier-mediated process.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗

PubMed1983

Synthesis, binding and intracellular retention of methotrexate polyglutamates by cultured human breast cancer cells.

Synthesis, binding, and intracellular retention of methotrexate polyglutamates by cultured human breast cancer cells were investigated by gel filtration and high-pressure liquid chromatography to separate methotrexate from its metabolites. MCF-7, ZR-75-1, and MDA-231 human breast cancer cells were found to readily convert methotrexate to higher polyglutamates during a 24-hr incubation period, although at differing rates. Examination of that portion of intracellular methotrexate specifically bound to dihydrofolate reductase revealed that, with prolonged incubation, methotrexate polyglutamates become the predominant drug form bound to the enzyme. Similarly, methotrexate polyglutamates accumulated free in the cytosol and when cells were suspended in drug-free medium, were retained intracellularly both bound to dihydrofolate reductase and in the unbound fraction, indicating their slow passage through the cell membrane. Studies of methotrexate polyglutamate binding to purified bacterial dihydrofolate reductase revealed high affinity binding for compounds with up to 6 additional glutamyl residues. These studies demonstrate that methotrexate polyglutamates are readily formed in human breast cancer cells, bind intracellularly to dihydrofolate reductase, and are selectively retained both bound to the enzyme and free in the cell cytosol.

Binding Sites↗

PubMed1994

Cell-type specific response of peripheral blood lymphocytes to methotrexate in the treatment of rheumatoid arthritis.

The mode of action of methotrexate in the treatment of rheumatoid arthritis is still questionable. Although in vitro results suggest an immunosuppressive effect of methotrexate, several clinical studies have failed to confirm these effects in patients treated with oral low-dose methotrexate. With respect to the highly variable bioavailability of methotrexate, we investigated the effects of an intravenous administration of 15 mg methotrexate per week on peripheral blood lymphocyte subsets in eight patients with rheumatoid arthritis. Methotrexate after 12 weeks significantly (P < 0.01) reduced total peripheral blood lymphocytes and led to a pronounced redistribution of lymphocyte subsets with a preferred reductive effect on B-lymphocytes (P < 0.005) and T-lymphocytes (P < 0.05). Natural killer cells and killer cell-like T cells, on the other hand, were unaffected by the treatment. Our results suggest a cell-type specific effect of intravenously administered low-dose methotrexate on peripheral blood lymphocytes. This effect, in our opinion, may contribute to the mode of action of methotrexate as an immunosuppressive drug in the treatment of rheumatoid arthritis.

Adult↗

PubMed1985

Urinary pH and urine flow independent renal clearance of methotrexate in dogs.

The effects of urine flow and pH on methotrexate renal clearance were studied in seven conditioned male Beagle-Mongrel dogs. Steady-state plasma methotrexate and inulin concentrations were achieved by i.v. infusions preceded by i.v. bolus doses. Plasma and urine concentrations of methotrexate were quantitated by a sensitive high-performance liquid chromatographic assay, while those of inulin were measured by a colorimetric method. Since plasma protein binding of methotrexate was pH and concentration independent, methotrexate/inulin renal clearance without correcting for plasma binding was used for most of the data analyses. The results showed that the renal clearance ratios at the plasma methotrexate levels (approximately 0.1, 1.0, 20.0 and 100 micrograms/ml) studied remained relatively constant when urine pH (differences of up to about 2.5 units) and flow rate (differences of up to approximately 30 times) were changed. This indicated that renal reabsorption of methotrexate in these dogs was negligible. However, concentration-dependent renal clearance was observed. The mean renal clearances were 3.84, 3.94, 2.73, and 2.72 ml/min/kg at plasma concentrations of about 0.1, 1.0, 20.0, and 100.0 micrograms/ml, respectively, when urine was alkalized by sodium bicarbonate. The corresponding clearances were 4.02, 4.28, 2.62,and 2.65 ml/min/kg when urine was acidified by ammonium chloride. These showed the existence of saturable tubular secretion of methotrexate. No 7-hydroxy-methotrexate, a metabolite found in other species, was detected in the urine and plasma of the dogs.

Animals↗

PubMed1983

Regulatory aspects of the glutamylation of methotrexate in cultured hepatoma cells.

The glutamylation of methotrexate has been evaluated in H35 hepatoma cells in vitro as a function of the conditions of culture. Glutamylation yields methotrexate polyglutamate with two to five additional glutamate residues and is a saturable process. The rate of glutamylation increases little above 10 microM extracellular methotrexate which corresponds to an intracellular concentration of approximately 4 microM. The rate of glutamylation measured over a 6-h period was stimulated by a reduction in cellular folates and prior incubation of the cells with insulin. Glutamylation was also more rapid in dividing cultures than in confluent cells. The combination of insulin inclusion and folate reduction, which was additive, caused approximately a fourfold increase in the rate of glutamylation over control cells under the conditions tested. The maximal rate of methotrexate glutamylation, which was 100 nmol/g/h, occurred in folate-depleted, insulin-supplemented cells. Supplementing folate-depleted cells with reduced folate coenzymes caused the glutamylation to be reduced by more than 90%. The turnover of methotrexate polyglutamates in cells saturated with these derivatives occurred at approximately one-half the rate of net synthesis and was stimulated to nearly the same extent by folate depletion and insulin. In addition to showing that folates can modify the rates of methotrexate polyglutamate formation, data are presented suggesting that methotrexate polyglutamates can regulate their own synthesis. The consequences of the formation of these retained forms of methotrexate in H35 hepatoma cells (M. Balinska, J. Galivan, and J.K. Coward (1981) Cancer Res. 41,2751-2756) and the effects of potential regulators of this process are discussed in terms of the glutamylation of folates in the cells and the chemotherapeutic effects of antifolates.

Animals↗

PubMed1984

A fluorescent analogue of methotrexate as a probe for folate antagonist molecular receptors.

A dansyl-L-lysine analogue of methotrexate, N alpha-(4-amino-4-deoxy-10- methylpteroyl )-N epsilon-(5-[N,N-dimethylamino]-1-naphthalenesulfonyl)-L-lysine, is a potent inhibitor of murine L1210 dihydrofolate reductase. The dansyl fluorescence emission was enhanced approximately 3-fold with a 10 nm blue shift upon binding to L1210 dihydrofolate reductase. The fluorescent analogue was only 10-fold less potent than methotrexate in inhibiting the growth of methotrexate-sensitive and -resistant L1210 cells and competes effectively for [3H]methotrexate transport with a Ki of 7.02 microM, a value virtually identical to the Kt for methotrexate in both cell lines. In addition, strong dansyl fluorescence was found to be associated with dihydrofolate reductase from methotrexate-resistant, dihydrofolate reductase-overproducing L1210 cells following incubation of viable cells with the fluorescent methotrexate analogue for 4 hr. The results demonstrate that the dansyl-L-lysine analogue of methotrexate was rapidly transported into L1210 cells where it formed a high-affinity, fluorescent complex with intracellular dihydrofolate reductase.

Animals↗

PubMed1986

Further studies on substituted quinazolines and triazines as inhibitors of a methotrexate-insensitive murine dihydrofolate reductase.

Data are presented on the systematic analysis of thirty-five quinazoline and substituted triazine compounds as inhibitors of a methotrexate-insensitive form of dihydrofolate reductase purified from methotrexate-resistant L5178Y murine leukemia cells. Several of the compounds were found to be more potent inhibitors of this enzyme activity than was methotrexate. Two of the triazine compounds had IC50 values approaching 10nM, which is close to that of methotrexate for the normal drug-sensitive dihydrofolate reductase. In addition, some of these compounds, especially the triazines, exhibit a specificity of inhibition for the methotrexate-insensitive enzyme as compared to the normal methotrexate-sensitive dihydrofolate reductase derived from the same cell line. These compounds may, therefore, be potentially useful in the treatment of those methotrexate-resistant tumours which express an altered, methotrexate-insensitive dihydrofolate reductase.

Animals↗

PubMed1987

Transport of folate compounds by leukemic cells. Evidence for a single influx carrier for methotrexate, 5-methyltetrahydrofolate, and folate in CCRF-CEM human lymphoblasts.

Influx kinetics and inhibitor specificity have been compared for the transport of methotrexate, 5-methyltetrahydrofolate, and folate in CCRF-CEM human lymphoblastoid cells. Influx of each folate compound proceeded with approximately the same Vmax, fluctuated in the same fashion with the ionic composition of the medium, and was blocked by low concentrations of an N-hydroxysuccinimide ester of methotrexate in both an anion-deficient buffer and in a buffered saline medium containing physiological concentrations of glucose and bicarbonate. Moreover, methotrexate influx was inhibited by 5-methyltetrahydrofolate and folate, and the inhibition constants (Ki) of the latter compounds were equivalent to their Kt values for half-maximal influx. Folate influx was likewise inhibited by methotrexate. The Ki for methotrexate was equivalent to its Kt for influx, and o-phthalate and phosphate each inhibited folate and methotrexate with the same degree of effectiveness. Various reversible and irreversible inhibitors reduced the influx of each folate substrate by greater than 90%, and the progression of inhibition in each case was indicative of a single uptake component. Folate influx exhibited the same high sensitivity to inhibitors of methotrexate influx when measurements were performed at folate concentrations near the Kt for influx (10-50 microM) or at concentrations approximating physiological conditions (5-20 nM). These results indicate that CCRF-CEM cells possess a single shared transport system for the uptake of methotrexate, 5-methyltetrahydrofolate, and folate and that other high- or low-affinity uptake processes are not present in these cells.

Biological Transport↗

PubMed1984

Radioimmunoassays of 7-hydroxymethotrexate and methotrexate.

Antisera against 7-hydroxymethotrexate were raised in rabbits by injection of 7-hydroxymethotrexate coupled to bovine serum albumin. A 125I-radiolabelled probe was synthesised by radioiodination of 7-hydroxymethotrexate conjugated to tyrosine methyl ester. We developed with these reagents a liquid phase radioimmunoassay for 7-hydroxymethotrexate in which methotrexate did not interfere significantly (cross-reactivity factor = 2.5 X 10(-4]. Similar techniques were used also for the development of a specific radioimmunoassay for methotrexate, which minimally cross-reacted with 7-hydroxymethotrexate. The assessment of the specificity of these assays showed that parallel monitoring of methotrexate and 7-hydroxymethotrexate in human plasma was possible. Coefficients of variation for duplicate determinations were less than 15% between 0.06 and 1.2 nmol/l for methotrexate and between 0.08 and 9 nmol/l for 7-hydroxymethotrexate. Methotrexate and its oxidative metabolite, 7-hydroxymethotrexate, were quantified in plasma of patients following high-dose infusion (2 g over 24 h) by radioimmunoassay and high performance liquid chromatography. The agreement between the two techniques was found satisfactory, as evaluated by least square regression analysis (slopes 1.007 +/- 0.046 for 7-hydroxymethotrexate and 0.937 +/- 0.046 for methotrexate with y-axis intercept not significantly different from zero). These radioimmunoassays permitted also the evaluation of the concentrations of methotrexate and 7-hydroxymethotrexate in plasma after intravenous bolus injection (50 mg/m2), and large inter-individual difference in both methotrexate and 7-hydroxymethotrexate kinetic behaviour could be observed.

Animals↗

PubMed1996

Oral methotrexate and vaginal misoprostol for early abortion.

Intramuscular methotrexate followed by vaginal misoprostol has been shown to be effective for abortion at < or = 49 days gestation. Oral dosing of the methotrexate may offer advantages over parenteral dosing. This pilot study was performed to evaluate if oral methotrexate would be effective when combined with vaginal misoprostol to effect abortion at < or = 49 days gestation. Twenty pregnant women were randomized to receive methotrexate 25 mg or 50 mg followed 7 days later by misoprostol 800 micrograms vaginally. The misoprostol dose was repeated the next day if the abortion did not occur. Complete abortion occurred in all subjects in both groups within 20 days after the methotrexate. However, women in the 50 mg group passed the pregnancy within 24 hours of the first or second dose of methotrexate more often than women in the 25 mg group (80% vs. 50%, p = 0.35). Vaginal bleeding lasted 12.1 +/- 3.1 days and 9.4 +/- 4.5 days in immediate success and delayed success patients, respectively. Oral methotrexate may be an effective alternative to intramuscular methotrexate in treatment regimens for nonsurgical abortion.

Abortifacient Agents↗

PubMed1996

Treatment of the small unruptured ectopic pregnancy: a cost analysis of methotrexate versus laparoscopy.

OBJECTIVE: To compare the economic costs between two strategies for management of the small unruptured ectopic pregnancy: initial treatment with methotrexate versus initial treatment with laparoscopic salpingostomy. METHODS: We assumed that both treatment strategies would result in identical clinical outcomes: resolution of the ectopic pregnancy without maternal mortality or long-term morbidity. Based on a literature review, estimates were derived for the likely clinical outcomes of a single injection of methotrexate (50 mg/m2) and for the likely clinical outcomes of the laparoscopy strategy. A range of values was evaluated for the initial success rate of each strategy and varying assumptions made about the type of treatment modality used for initial treatment failures. Direct medical costs of each strategy were estimated based on actual reimbursement rates of a third-party payer for the components of each strategy. The treatment strategies were compared in best-case/worst-case scenarios to determine the potential range of differences in costs between the two strategies. RESULTS: The cost of the methotrexate strategy ranged from $438 to $1390, and the cost of laparoscopic salpingostomy ranged from $2506 to $2974; therefore, the methotrexate strategy was less costly than laparoscopy, with a cost difference ranging from $1124 (best-case laparoscopy-worst-case methotrexate scenario) to $2536 (worst-case laparoscopy-best-case methotrexate scenario). Sensitivity analyses demonstrated that initial therapy with methotrexate was less costly over a wide range of probability and cost estimates. CONCLUSION: Initial methotrexate is a cost-effective alternative to laparoscopic salpingostomy in the treatment of the small unruptured ectopic pregnancy.

Costs and Cost Analysis↗