The effect of folic acid supplementation on the pharmacokinetics and pharmacodynamics of oral methotrexate during the remission-induction period of treatment for moderate-to-severe plaque psoriasis

Methotrexate polyglutamates

INTRODUCTION

Methotrexate polyglutamates (MTXPGs) are intracellular metabolites of methotrexate (MTX) that play a critical role in the drug's activity, influencing both its efficacy and toxicity. As the exact implications of MTXPGs in these processes remain a subject of debate, a comprehensive review of MTXPGs could provide valuable insights for clinicians and pharmacists, potentially minimizing adverse reactions and enhancing therapeutic outcomes.

AREAS COVERED

A comprehensive search of relevant literature was conducted in PubMed and Web of Science databases, including studies from their inception to April 2024. Eligible studies included reviews, clinical trials, and real-world analyses. Additional manual searches and citation reviews were also performed. This review aims to explore MTXPGs with a primary focus on their pharmacokinetics, analytical methods, determinants of drug exposure, and their correlation with MTX efficacy and toxicity.

EXPERT OPINION

MTXPGs have not yet garnered significant attention in clinical practice. However, multiple studies have demonstrated a relationship between MTXPGs and the efficacy and toxicity of MTX, suggesting a potential avenue for personalized treatment strategies. Future research should aim to further validate and refine this correlation. Additionally, attention should also be directed toward other metabolites of MTX, which may hold clinical significance.

Basic Therapeutic Approach for Patients with Plaque Psoriasis: Korean Expert Consensus Using the Modified Delphi Method

BACKGROUND

Currently, there is no consensus on the treatment of psoriasis in Korean patients.

OBJECTIVE

This study aimed to establish a consensus on the basic therapeutic principles for Korean patients with plaque psoriasis.

METHODS

Using the modified Delphi method, a steering committee proposed 53 statements for the first Delphi round, which covered five subjects: (1) the goal of treatment and evaluation of disease severity, (2) topical therapy, (3) phototherapy, (4) conventional systemic therapy, and (5) biologic therapy. The panel of dermatologists scored the level of agreement for each statement on a ten-point scale with scores ranging from 1 (strongly disagree) to 10 (strongly agree). After discussing the results of the first round, the committee reformulated 41 statements. Finally, consensus was defined as more than 70% of the second round scores being ≥7.

RESULTS

The panel participants strongly agreed that the ideal treatment goals for Korean patients with plaque psoriasis should include complete skin clearance and high dermatological quality of life. A strong consensus was also reached on the use of topical agents for psoriasis of any severity, the consideration of phototherapy before biologics therapy, the conventional systemic agents for moderate-to-severe psoriasis, and the recommendation of biologic for retractable psoriasis to conventional systemic therapy and phototherapy.

CONCLUSION

This modified Delphi panel established an expert consensus on the therapeutic approach for Korean patients with plaque psoriasis. This consensus may improve the treatment outcomes for psoriasis in Korea.

Methotrexate Dosing Regimen for Plaque-type Psoriasis: An Update of a Systematic Review

Background Methotrexate (MTX) is a systemic treatment for plaque-type psoriasis. At the time of approval, no dose-ranging studies were performed. Nowadays, a uniform dosing regimen is lacking. This might contribute to suboptimal treatment with the drug.Objective To summarize the literature involving the MTX dosing regimens in psoriasis patients.Methods In this SR, RCTs and documents with aggregated evidence (AgEv) on the MTX dosing regimen in psoriasis were summarized. All randomized controlled trials (RCTs) in which oral, subcutaneous or intramuscular MTX was used in patients with psoriasis and AgEv, were included. The MEDLINE, EMBASE and CENTRAL databases were searched up to June 20, 2022. This SR was registered in PROSPERO.Results Thirty-nine RCTs had a high risk of bias. Test dosages were given in only 3 RCTs. In the RCTs, MTX was usually prescribed in a start dose of 7.5 mg/week (n = 13). MTX was mostly given in a start dose of 15 mg/week, in the AgEv (n = 5). One guideline recommended a test dose, in other aggregated evidence a test dose was not mentioned or even discouraged.Conclusions There is a lack of high-quality evidence and available data for dosing MTX in psoriasis is heterogeneous.

The safety of commonly used vitamins and minerals

Dietary supplements are the most common type of complementary medicine in Australia, reportedly used by 47% of the population. Vitamins and minerals are particularly popular

Like all medicines, supplements can cause potential harms such as adverse reactions, drug interactions, monetary cost, delay of more effective therapy, false hope, and increased medication burden

Although most vitamins and minerals are available for open sale, many are subject to legal restrictions as scheduled medicines, depending on the dose

Consumers are at risk of overdose when the same ingredient is present in multiple products

Health professionals can assist consumers by discussing the potential benefits and harms of vitamins and minerals and assisting them to find authoritative information

Adverse events with vitamins and minerals should be reported to the Therapeutic Goods Administration

A Review of Clinical Applications and Side Effects of Methotrexate in Ophthalmology

Methotrexate (MTX) is a folate analog widely used against a range of diseases including malignancies and autoimmune disorders. Its high effectiveness-price ratio also won extensive application in ophthalmology. On the other hand, although MTX has an excellent pharmacological efficacy, MTX associated side effects in clinical use, which vary from patient to patient, are nonnegligible. There is no comparatively systematic review on MTX associated side effects and its risk factors. This review aimed to reveal novel clinical approaches of MTX and its adverse effects in order to provide a reference for ophthalmic scholars in clinical application of MTX.

Folate Nutritional Status among Psoriasis Patients not Exposed to Antifolate Drug

Background:

Folic acid fortification program has been established to prevent tube defects. However, concern has been raised among patients using anti-folate drug, i.e. psoriatic patients, a common, chronic, autoimmune inflammatory skin disease associated with obesity and smoking.

Objective:

To investigate dietary and circulating folate, vitamin B12 (B12) and homocysteine (hcy) in psoriatic subjects exposed to the national mandatory folic acid fortification program.

Methods:

Cross-sectional study using the Food Frequency Questionnaire, plasma folate, B12, hcy and psoriasis severity using the Psoriasis Area and Severity Index score. Median, interquartile ranges (IQRs) and linear regression models were conducted to investigate factors associated with plasma folate, B12 and hcy.

Results:

82 (73%) mild psoriasis, 18 (16%) moderate and 12 (11%) severe psoriasis. 58% female, 61% non-white, 31% former smokers, and 20% current smokers. Median (IQRs) were 51 (40, 60) years. Only 32% reached the Estimated Average Requirement of folate intake. Folate and B12 deficiencies were observed in 9% and 6% of the blood sample respectively, but hyperhomocysteinaemia in 21%. Severity of psoriasis was negatively correlated with folate and B12 concentrations. In a multiple linear regression model, folate intake contributed positively to 14% of serum folate, and negative predictors were psoriasis severity, smoking habits and saturated fatty acid explaining 29% of circulating folate.

Conclusion:

Only one third reached dietary intake of folate, but deficiencies of folate and B12 were low. Psoriasis severity was negatively correlated with circulating folate and B12. Stopping smoking and a folate rich diet may be important targets for managing psoriasis.

Joint American Academy of Dermatology-National Psoriasis Foundation guidelines of care for the management of psoriasis with systemic nonbiologic therapies

Psoriasis is a chronic inflammatory disease involving multiple organ systems and affecting approximately 2% of the world's population. In this guideline, we focus the discussion on systemic, nonbiologic medications for the treatment of this disease. We provide detailed discussion of efficacy and safety for the most commonly used medications, including methotrexate, cyclosporine, and acitretin, and provide recommendations to assist prescribers in initiating and managing patients on these treatments. Additionally, we discuss newer therapies, including tofacitinib and apremilast, and briefly touch on a number of other medications, including fumaric acid esters (used outside the United States) and therapies that are no longer widely used for the treatment of psoriasis (ie, hydroxyurea, leflunomide, mycophenolate mofetil, thioguanine, and tacrolimus).

Methotrexate Hepatotoxicity and the Impact of Nonalcoholic Fatty Liver Disease

Methotrexate (MTX) is commonly used to treat individuals with rheumatological and dermatologic disorders. Current American College of Rheumatology (ACR) and American Association of Dermatology (AAD) guidelines identify diabetes and obesity as risk factors for MTX-induced liver injury. Both diabetes and obesity are components of the metabolic syndrome, and are also risk factors for nonalcoholic fatty liver disease (NAFLD). NAFLD affects approximately 40% of the U.S. population, and those with more advanced NAFLD (i.e., nonalcoholic steatohepatitis with or without fibrosis) are likely to develop progressive liver disease. As such, individuals who are treated with MTX may need to be screened for advanced NAFLD, as this may put them at an increased risk of MTX-induced liver injury. In this mini-review, we review the current ACR and AAD guidelines on MTX hepatotoxicity, discuss the evidence (or lack thereof) of the impact of metabolic risk factors on MTX-induced liver injury and highlight the areas that need further research.

Pharmacokinetic profile of methotrexate in psoriatic skin via the oral or subcutaneous route using dermal microdialysis showing higher methotrexate bioavailability in psoriasis plaques than in non-lesional skin

AIMS

The aim of this pilot study was to use microdialysis to evaluate levels of Methotrexate (MTX) directly in psoriatic skin following oral or subcutaneous administration of MTX to elaborate a complete pharmacokinetic profile within the dermal skin.

METHODS

Six patients with chronic plaque psoriasis on the arm undergoing treatment with MTX were included in a mono-centre clinical trial. Patients were under treatment with p.o. or s.c. MTX (7.5 and 15 mg) for at least 3 months. Interstitial fluid was collected ex vivo via dermal microdialysis from lesional or non-lesional skin and via intravenous microdialysis as well as blood serum every hour up to 10 h after methotrexate administration every hour. MTX was analysed via liquid chromatography.

RESULTS

The area under the curve (AUC) of methotrexate from peripheral blood was up to four times higher than from microdiaylsis, which detection of free unbound MTX. The AUC from dialysates in psoriatic lesional skin was higher than in non-lesional psoriatic skin, and the AUC levels from i.v. microdialysis were non-significantly higher than those from lesional psoriatic skin. Pharmacokinetic profiles were individually quite different and did not primarily depend on the dose or the means (p.o. vs. s.c.) in which it was administered.

CONCLUSION

Dermal microdialysis is a valid tool to evaluate levels of methotrexate in the skin of psoriasis patients. Drug levels and bioavailability of methotrexate were higher in lesional than non-lesional psoriatic skin. The individual AUC of MTX was not primarily dependent on the route or dose of administration.

Systemic methotrexate for the treatment of psoriasis

In the era of biologic therapies, methotrexate (MTX), a classic immunomodulator, is still the cornerstone of systemic treatment of psoriasis. MTX has been used for many years, achieving good responses with a good safety profile. However, only a few randomized clinical trials have been performed involving MTX, and most of the current evidence comes from pivotal studies of biologic drugs. The aim of this article is to make an extensive review of the MTX mechanism of action, pharmacokinetics, efficacy, safety and tolerability, especially focusing on the future perspective of this old drug and recent advances in the field of pharmacogenetics.

Efficacy of the apitherapy in the treatment of recalcitrant localized plaque psoriasis and evaluation of tumor necrosis factor-alpha (TNF-α) serum level: A double-blind randomized clinical trial

BACKGROUND

No universal consensus about optimal modality for treating the recalcitrant localized plaque psoriasis (RLPP) is available.

OBJECTIVE

To evaluate the immunological and clinical therapeutic effect of using apitherapy in the treatment of RLPP.

METHODS

Randomized 50 patients with RLPP received apitherapy (n = 25) and placebo (n = 25) every week. Both treatments were injected into lesions at weekly intervals for a maximum of 12 treatments. Following up was 6 months later. Tumor necrosis factor-alpha (TNF-α) level was measured at pre-study and at 12th week.

RESULTS

A significant difference was found between the therapeutic responses of RLPP to the apitherapy and placebo groups (p<0.001). In the apitherapy group, complete response was achieved in 92% of patients. There was statistically significant decrease in TNF-α in the apitherapy group compared to the placebo group. No recurrence was observed in the apitherapy group.

CONCLUSION

Apitherapy is effective and a safe treatment for recalcitrant localized plaque psoriasis, when other topical or physical therapies have failed.

Sugarcane bagasse lignin, and silica gel and magneto-silica as drug vehicles for development of innocuous methotrexate drug against rheumatoid arthritis disease in albino rats

The present study clarifies co-therapy action of deliveries from their textural changes point of view. Methotrexate (MTX) was immobilized onto biodegradable lignin, silica gel and iron/silica nanocomposite. Loaded-MTX was i.p. injected into albino rats at doses of 0.25 and 0.5mg/kg/week for 2.5months, after which spleen, liver, testes and knee joint tissues were collected for tests. IFN-γ and IL-17A mRNA gene expressions in spleen in all biological samples were determined by RT-PCR. Physicochemical features of drug carriers were monitored by XRD, BET-PSD, SEM and TEM. Drug inflammatory-site targeting was found to be closely related to the physico-features of deliverers. The interlayered lignin of micro- and meso-pore channels directed MTX toward concealed infected cells in liver and testes tissues, while meso-structured silica flacks satisfied by gathering MTX around knee joints. The magneto-silica nanocomposite targeted MTX toward spleen tissue, which is considered as a lively factory for the production of electron rich compounds.

The possibilities and principles of methotrexate treatment of psoriasis - the updated knowledge

Psoriasis is a chronic multifactorial disease affecting 2–4% of the general population. Due to its nature, psoriasis has a negative impact on the quality of life of patients. Therefore, the choice of an appropriate and individually tailored treatment controlling the symptoms of the disorder is necessary and continues to be a challenge for dermatologists. Therapeutic modalities in psoriasis should on the one hand be effective and on the other hand present a good safety profile. Methotrexate (MTX) is one of treatment options for psoriasis and can be administered both as monotherapy or in combination schemes. The paper presents the current state of knowledge about the possible treatment of psoriatic patients with MTX according to contemporary guidelines.

Methotrexate toxicity during treatment of chronic plaque psoriasis: a case report and review of the literature

Methotrexate continues to be one of the most widely used systemic immunosuppressive agents in dermatology. In addition to the important, well-characterized adverse effects such as hepatotoxicity and myelosuppression, methotrexate may induce a number of rare cutaneous adverse events including methotrexate-induced ulceration. We present a case of methotrexate-induced cutaneous ulceration in a patient with chronic plaque psoriasis occurring during long-standing methotrexate therapy. Withdrawal of the drug and appropriate skin care led to rapid healing of the ulceration and the agent was later safely reintroduced for the ongoing management of the patient's chronic plaque psoriasis. Review of the literature demonstrates cases of this important rare adverse event, primarily occurring in patients with chronic plaque psoriasis, induced by triggers such as accidental overdose or introduction of an interacting agent. Cutaneous ulceration typically precedes other markers of toxicity. Active treatment with folinic acid (calcium leucovorin) may be required. Early recognition, prompt cessation of methotrexate, and appropriate treatment minimizes morbidity. Dermatologists need to be alert to the possibility of cutaneous adverse events associated with methotrexate therapy, aware of potential drug interactions, and confident in the management of methotrexate toxicity.

Diet in dermatology: Part II. Melanoma, chronic urticaria, and psoriasis

The roles of dietary factors in aggravating, preventing, or treating skin diseases are common questions encountered in dermatology practice. Part II of this two-part series reviews dietary modifications that can potentially be utilized in the management of melanoma, chronic urticaria, and psoriasis patients. Specifically, we examine the effect of alcohol consumption and supplementation with vitamins D and E, polyunsaturated fatty acids, selenium, green tea, resveratrol, and lycopene on melanoma risk. The relationships between chronic urticaria symptoms and dietary pseudoallergens, gluten, and vitamin D are analyzed. We explore weight loss, reduced alcohol consumption, and gluten avoidance as means of reducing psoriasis-associated morbidity, as well as the possible utility of supplementation with polyunsaturated fatty acids, folic acid, vitamin D, and antioxidants. With proper knowledge of the role of diet in these cutaneous disease processes, dermatologists can better answer patient inquiries and consider implementation of dietary modifications as adjuncts to other treatments and preventative measures.

Considerable variation among Iranian dermatologists in the dosing and monitoring of methotrexate for treating psoriasis

BACKGROUND

Methotrexate (MTX) is a risky medication requiring careful attention to dosing and monitoring. Dosing and monitoring practices are not well characterized.

AIMS

The aim of this study was to assess variation in the dosing and monitoring of methotrexate among Iranian dermatologists.

METHODS

A questionnaire was administered to forty experts in psoriasis concerning the use of MTX.

RESULTS

Among the 39 responding dermatologists (15 women, 24 men), 54% saw fewer than 10 psoriatic patients per week, 23% 10-20 patients, and 23% more than 20 patients. About half of the dermatologists treat their patients with an initial MTX dose of <7.5 mg/week (range 5-17.5 mg/week), an average dose of <10 mg/week (range 5-25 mg/week), and a maximum dose of <20 mg/week (range 7.550 – mg/week) with 71.8% prescribing the medication orally and 28.2% intramuscularly. Subcutaneous injection was preferred by none of the dermatologists as a usual route of administration. Nearly 5% of the dermatologists believe that liver biopsy should be performed prior to treatment with MTX in all patients, and another 5% consider this procedure prior to treatment only in patients with risk factors. About 44 and 33% of the dermatologists do the liver biopsy after 1.0-1.5 g and 3.54 g total cumulative doses, respectively.

CONCLUSION

After more than a half century, there are still noticeable controversies on the manner of using MTX in treating psoriasis among Iranian dermatologists. A national guideline may help standardize treatment practices.

The effect of folate supplementation on methotrexate efficacy and toxicity in psoriasis patients and folic acid use by dermatologists in the USA

BACKGROUND

Methotrexate (MTX) is an effective treatment for psoriasis but its use is limited by its toxicity. Folate supplementation can be used to reduce the adverse effects of MTX, though this may impact efficacy. The frequency of folic acid supplementation is not well characterized.

PURPOSE

The objective of this study was to review the literature involving the use of folate in patients (in particular those with psoriasis) treated with MTX and analyze trends in folic acid use.

METHODS

We searched PubMed from 1 May 1989 through 1 April 2012 using the terms 'folic acid,' 'folinic acid,' 'folate,' 'supplementation,' and 'methotrexate.' We also used the National Ambulatory Medical Care Survey (NAMCS) database to collect data regarding trends in MTX use and folic acid supplementation by physicians in the USA from 1993 through 2009. We assessed data including the number of MTX visits, rate of folic acid use, diagnoses, physician specialty, and demographics of patients. We used linear regression to analyze the change in folic acid use over time.

RESULTS

Twenty-six published trials were included addressing folic acid supplementation with MTX. The majority found a benefit to folic acid supplementation, but there were only seven studies in psoriasis. Dermatologists were among the highest prescribers of MTX, and psoriasis was commonly treated with MTX. Folic acid supplementation significantly increased over this time period (p < 0.0001). However, dermatologists ranked lowest for their folate use, co-prescribing folate to only 9.1 % of MTX-treated patients.

LIMITATIONS

In contrast to rheumatoid arthritis, there is a scarcity of literature describing the effect of folate on MTX toxicity and efficacy in psoriasis patients. NAMCS data only included outpatient visits to non-federally employed physicians, and there is the possibility of healthcare providers not documenting over-the-counter folic acid usage. Lastly, doses of MTX and folic acid were not recorded in the database.

CONCLUSION

Dermatologists were the least likely specialists to supplement MTX with folic acid. The evidence for supplementation of folic acid is mixed. The literature confirms a reduction in the adverse effects of MTX but less strongly that there may be a reduction in efficacy too. Keeping in mind the potential for folate to reduce MTX efficacy, folic acid supplementation should be considered in MTX-treated patients.

A consensus report on appropriate treatment optimization and transitioning in the management of moderate-to-severe plaque psoriasis

BACKGROUND

There is limited information on systemic and biological treatment optimization and transitioning in routine clinical practice.

OBJECTIVE

To provide practical guidance on treatment optimization and transitioning for moderate-to-severe plaque psoriasis.

METHODS

Dermatologists from 33 countries contributed to the Transitioning Therapies programme. Fourteen questions were identified. Answers were drafted based on systematic literature reviews (7/14 questions) and expert opinion (7/14 questions). Using a modified Delphi procedure, dermatologists from 30 countries voted on their level of agreement with each draft answer (scale: 1-9, strong disagreement to strong agreement). Consensus was defined as ≥75% of participants scoring within the 7-9 range.

RESULTS

Consensus was achieved on the answers to all questions. Recommendations for the use of cyclosporine and methotrexate were agreed. Transitioning from a conventional systemic therapy to a biological agent may be done directly or with an overlap (if transitioning is required because of lack of efficacy) or potentially with a treatment-free interval (if transitioning is required for safety reasons). Combination therapy may be beneficial. Continuous therapy for patients on biologicals is strongly recommended. However, during successful maintenance with biological monotherapy, a dosage reduction may be considered to limit drug exposure, although this may carry the risk of decreased efficacy. Switching biologicals for reasons of efficacy should be done without a washout period, but switching for reasons of safety may require a treatment-free interval.

CONCLUSION

This consensus provides practical guidance on treatment optimization and transitioning for moderate-to-severe plaque psoriasis, based on literature reviews and the expert opinion of dermatologists from across the globe.

Which antipsoriatic drug has the fastest onset of action? Systematic review on the rapidity of the onset of action

The time necessary for a treatment to become effective is crucial for patients and physicians but has been largely neglected in the reporting and comparison of clinical trials in dermatology. The aim of this systematic review is to determine the time until the onset of action (TOA) of systemic agents approved for moderate-to-severe psoriasis. Primary outcome is the TOA defined as the weighted mean time until 25% of the patients achieved a psoriasis area and severity index (PASI) 75 response. Among the biologics, infliximab has the shortest TOA (3.5 weeks), followed by ustekinumab (high dose 4.6/low dose 5.1 weeks/not weight adapted), adalimumab (4.6 weeks), etanercept (high dose 6.6/low dose 9.5 weeks), and alefacept (high dose 15.4 weeks/low dose: no data). Among the conventional treatments, good data are available for cyclosporine A (CsA; TOA: 6.0 weeks) and limited data are found for methotrexate (MTX; TOA: high dose 3.2/low dose 9.9 weeks). No data are available for fumaric acid esters and retinoids. This systematic review provides clinically relevant information on the onset of action of antipsoriatic agents, although the data currently available allow only a limited assessment. Psoriasis trials should consider including TOA as an additional outcome measure.

S3 - Guidelines on the treatment of psoriasis vulgaris (English version). Update

Psoriasis vulgaris is a common and often chronic inflammatory skin disease. The incidence of psoriasis in Western industrialized countries ranges from 1.5% to 2%. Patients afflicted with severe psoriasis vulgaris may experience a significant reduction in quality of life. Despite the large variety of treatment options available, surveys have shown that patients still do not received optimal treatments. To optimize the treatment of psoriasis in Germany, the Deutsche Dermatologi sche Gesellschaft (DDG) and the Berufsverband Deutscher Dermatologen (BVDD) have initiated a project to develop evidence-based guidelines for the management of psoriasis. They were first published in 2006 and updated in 2011. The Guidelines focus on induction therapy in cases of mild, moderate and severe plaque-type psoriasis in adults including systemic therapy, UV therapy and topical therapies. The therapeutic recommendations were developed based on the results of a systematic literature search and were finalized during a consensus meeting using structured consensus methods (nominal group process).

Effect of genetic polymorphisms in the folate pathway on methotrexate therapy in rheumatic diseases

Methotrexate (MTX) is the first-line treatment for rheumatoid arthritis and is frequently used in the management of other forms of inflammatory arthritis. It is currently challenging to predict which patients will achieve adequate disease control and which patients will develop adverse effects while taking MTX. As an analog of dihydrofolic acid, MTX enters cells through the reduced folate carrier-1 protein, and is polyglutamated. MTX polyglutamates inhibit key enzymes in the folate pathway to produce an anti-inflammatory effect. It has been suggested that genetic polymorphisms in the folate pathway may influence intracellular folate and MTX polyglutamates pools, and thus MTX response. However, studies to identify genetic predictors have yielded inconclusive results. Nonreplication across studies has been attributed to insufficient statistical power as well as pharmacological and clinical confounders. Prospective studies, standardizing the definitions of response and toxicity, and application of genome-wide approaches may advance the search for genetic predictors of MTX response.

The Use of Methotrexate in Dermatology / Upotreba metotreksata u dermatologiji

Methotrexate is a cytotoxic antimetabolite agent and a folic acid antagonist. Except for its use in oncology and rheumatology, it is widely used in dermatology. The most important indications include severe forms of psoriasis, but also a wide range of autoimmune diseases and dermatoses with different etiology and pathophysiology such as: bullous pemphigoid, dermatomyositis, pityriasis rubra pilaris, sarcoidosis, T-cell lymphomas, Behcet’s disease, adult atopic eczema, scleroderma, Reiter’s syndrome and many others. For dermatological indications methotrexate is usually taken in low oral doses, 5-25 mg once a week. In certain diseases it can be applied to the lesion itself, or in the form of local preparations. Considering the fact that numerous drugs affect various metabolic phases of methotrexate and may increase its toxicity, it is of utmost importance to consider other prescribed drugs, especially certain antibiotics, nonsteroidal antiinflammatory drugs, antiepileptic drugs, retinoids, proton pump inhibitors and so on. If the selection of patients is correct, if drugs are taken regularly and laboratory monitoring is included, methotrexate is a truly efficient and safe drug that can be taken for months or years if necessary.

[Guidelines on the use of methotrexate in psoriasis]

Psoriasis, a chronic multifactorial inflammatory disease that develops in genetically predisposed individuals, affects approximately 1.5% of the Spanish population. This disease has a negative impact on patients' quality of life, and long-term therapy is often required to control the symptoms. In addition to the classical systemic treatments (methotrexate, acitretin, cyclosporine, and ultraviolet light), the group of drugs known as biologics (etanercept, infliximab, adalimumab, and ustekinumab) provides the dermatologist with an expanded therapeutic armamentarium, thereby improving the likelihood of controlling psoriasis in patients with severe and/or extensive disease. Methotrexate, a classic antipsoriatic drug, is still very useful either as single-drug therapy or in combination with other systemic drugs, particularly as a rescue therapy or combined with biologics. This article aims to establish the role of methotrexate in the treatment of psoriasis. We considered it of interest to develop guidelines for using methotrexate in the management of psoriasis with a view to ensuring the safe and proper use of this drug in the management of psoriasis. This document was developed by consensus among members of the Psoriasis Group of the Spanish Academy of Dermatology and Venereology.

Assessment and management of methotrexate hepatotoxicity in psoriasis patients: report from a consensus conference to evaluate current practice and identify key questions toward optimizing methotrexate use in the clinic

Experts in psoriasis, hepatology, pharmacokinetics and pharmacogenetics convened to discuss the safety and monitoring of methotrexate with respect to hepatotoxicity when used in the treatment of psoriasis. Methotrexate is an efficacious and cost-effective treatment for psoriasis, but is associated with significant safety issues, particularly relating to hepatotoxicity. Current British, Dutch, German, EU and US guidelines for baseline evaluations, monitoring and prevention of hepatotoxicity in patients with psoriasis receiving methotrexate were evaluated. Liver safety monitoring is currently reliant upon multiple methods, including biopsy, serological tests for biomarkers such as type III procollagen amino terminal propeptide (PIIINP), and liver function tests based on liver enzymes. Monitoring of patients receiving long-term therapy is expected to be improved by the utilization of serum biomarkers currently in development such as the Enhanced Liver Fibrosis (ELF) panel and other non-invasive tests of hepatic architecture, such as fibroelastography, microbubbles and magnetic resonance imaging. Appropriate studies to determine optimal dosing to maximize efficacy and minimize toxicity, potentially utilizing pharmacogenetic principles, are clearly needed. Key questions for future research are identified including needs for optimal screening and monitoring, identification of appropriate biomarkers, assessment of relationships between dosing and safety, utility of liver biopsy, optimal dosing regimens (including route of administration), methods to measure methotrexate levels in blood, and use of methotrexate as a standardized active comparator in trials of experimental drugs used to treat psoriasis.

Red blood cell methotrexate polyglutamates emerge as a function of dosage intensity and route of administration during pulse methotrexate therapy in rheumatoid arthritis

OBJECTIVE

MTX is a prodrug producing anti-arthritic effects through a folylpolyglutamate synthase-mediated activation to MTX polyglutamates (MTXPGs). Our objective was to characterize the pharmacokinetics of intracellular MTXPGs and the factors associated with their accumulation in adult RA patients treated with MTX weekly.

METHODS

MTX pharmacokinetics were evaluated in 47 MTX-naïve patients enrolled in an MTX dose-escalation study for an average of 20 weeks and 223 patients enrolled in a cross-sectional study under long-term MTX therapy. Short-chain (MTXPG1-2), long-chain (MTXPG3) and very long-chain (MTXPG4-5) concentrations were measured in circulating red blood cells using liquid chromatography. Statistical analyses consisted of non-linear mixed models, multivariate regression analyses and Wilcoxon signed-rank test.

RESULTS

The accumulation of MTXPG1-5 was sigmoidal and steady-state concentrations were achieved after 7 weeks of therapy. However, additional exposure and MTX dosage escalation produced a selective redistribution towards longer chain MTXPGs at the expense of shorter chain MTXPGs. Age, glomerular filtration rate and route of MTX administration were the most important predictors of MTXPG accumulation. In 10 patients, a switch from oral to parenteral MTX was associated with a 37% increase in long-chain MTXPGs, a 132% increase in very long-chain MTXPGs and a concomitant 31% reduction in disease activity (P<0.02).

CONCLUSION

The selective emergence of long-chain MTXPGs is function of dose, time of exposure and hence dosage intensity. Switching from oral to parenteral MTX produces a selective accumulation of longer chain MTXPGs that are known to be more potent inhibitors of de novo purine biosynthesis than shorter chain MTXPGs.

Determinants of red blood cell methotrexate polyglutamate concentrations in rheumatoid arthritis patients receiving long-term methotrexate treatment

OBJECTIVE

Methotrexate (MTX) is the most commonly used disease-modifying antirheumatic drug (DMARD) in the management of rheumatoid arthritis (RA). MTX is transported into cells, where additional glutamate moieties are added and it is retained as MTX polyglutamates (MTXGlu [referred to as a group as MTXGlun]). There is large interpatient variability in MTXGlun concentrations. This study was undertaken to determine nongenetic factors that influence red blood cell (RBC) MTXGlun concentrations in patients receiving long-term stable low-dose oral MTX.

METHODS

One hundred ninety-two patients receiving long-term oral MTX for the treatment of RA were recruited. Trough MTXGlun concentrations were measured by high-performance liquid chromatography. Univariate analysis was performed to determine variables influencing MTXGlun concentrations. Backward stepwise multivariate regression analysis was done to determine variables that affect individual MTXGlun concentrations; variables with P values of <0.1 in the univariate analysis for any MTXGlun were included.

RESULTS

Univariate analysis revealed that increased age, lower estimated glomerular filtration rate (GFR), higher MTX dosage, longer duration of MTX treatment, and use of prednisone were associated with significantly higher MTXGlun concentrations. Smokers had significantly lower concentrations of MTXGlu3, MTXGlu3-5, and MTXGlu1-5. Sex, rheumatoid factor and anti-cyclic citrullinated peptide status, RBC folate level, and body mass index had no significant effect on MTXGlun levels. Concomitant use of other DMARDs was associated with lower MTXGlu2 levels, and treatment with nonsteroidal antiinflammatory drugs was associated with lower MTXGlu3 and MTXGlu1-5 concentrations. Multivariate regression analysis revealed that age, MTX dosage, and estimated GFR were the major determinants of MTXGlun concentrations.

CONCLUSION

Large interpatient variability in MTXGlun concentrations can be explained, at least in part, by a combination of factors, particularly age, MTX dosage, and renal function. There are complex interactions between smoking, RBC folate levels, and concentrations of MTXGlun.