A double-blind comparative study of hydroxychloroquine and dapsone, alone and in combination, in rheumatoid arthritis

Monotreatment With Conventional Antirheumatic Drugs or Glucocorticoids in Rheumatoid Arthritis: A Network Meta-Analysis

Importance

This is the first network meta-analysis to assess outcomes associated with multiple conventional synthetic disease-modifying antirheumatic drugs and glucocorticoid.

Objective

To analyze clinical outcomes after treatment with conventional synthetic disease-modifying antirheumatic drugs and glucocorticoid among patients with rheumatoid arthritis.

Data Sources

With no time restraint, English language articles were searched in MEDLINE, Embase, Cochrane Central, ClinicalTrials.gov, and reference lists of relevant meta-analyses until September 15, 2022.

Study Selection

Four reviewers in pairs of 2 independently included controlled studies randomizing patients with rheumatoid arthritis to mono-conventional synthetic disease-modifying antirheumatic drugs, glucocorticoid, placebo, or nonactive treatment that recorded at least 1 outcome of tender joint count, swollen joint count, erythrocyte sedimentation rate, and C-reactive protein level. Of 1098 assessed articles, 130 articles (132 interventions) were included.

Data Extraction and Synthesis

The review followed the Preferred Reporting Items for Systematic Reviews and Meta-analyses reporting guideline, and data quality was assessed by the Cochrane risk of bias tool RoB 2. Data were extracted by a single author and checked independently by 2 authors. Data were analyzed using a random effect model, and data analysis was conducted from June 2021 to February 2023.

Main Outcomes and Measures

A protocol with hypothesis and study plan was registered before data recording. The most complete of recorded outcomes (tender joint count) was used as primary outcome, with imputations based on other outcomes to obtain a full analysis of all studies. Absolute change adjusted for baseline disease activity was assessed.

Results

A total of 29 interventions in 275 treatment groups among 132 randomized clinical trials (mean [range], 71.0% [27.0% to 100%] females in studies; mean [range] of ages in studies, 53 [36 to 70] years) were identified, which included 13 260 patients with rheumatoid arthritis. The mean (range) duration of RA was 79 (2 to 243) months, and the mean (range) disease activity score was 6.3 (4.0 to 8.8). Compared with placebo, oral methotrexate was associated with a reduced tender joint count by 5.18 joints (95% credible interval [CrI], 4.07 to 6.28 joints). Compared with methotrexate, glucocorticoid (-2.54 joints; 95% CrI, -5.16 to 0.08 joints) and remaining drugs except cyclophosphamide (6.08 joints; 95% CrI, 0.44 to 11.66 joints) were associated with similar or lower tender joint counts.

Conclusions and Relevance

This study's results support the present role of methotrexate as the primary reference conventional synthetic disease-modifying antirheumatic drug.

Safety of Short-Term Treatments with Oral Chloroquine and Hydroxychloroquine in Patients with and without COVID-19: A Systematic Review

Chloroquine (CQ) and hydroxychloroquine (HCQ) have recently become the focus of global attention as possible treatments for Coronavirus Disease 2019 (COVID-19). The current systematic review aims to assess their safety in short treatments (≤14 days), whether used alone or in combination with other drugs. Following the PRISMA and SWiM recommendations, a search was conducted using four health databases for all relevant English-, Chinese-, and Spanish-language studies from inception through 30 July 2021. Patients treated for any condition and with any comparator were included. The outcomes of interest were early drug adverse effects and their frequency. A total of 254 articles met the inclusion criteria, including case and case-control reports as well as cross-sectional, cohort, and randomised studies. The results were summarised either qualitatively in table or narrative form or, when possible (99 studies), quantitatively in terms of adverse event frequencies. Quality evaluation was conducted using the CARE, STROBE, and JADAD tools. This systematic review showed that safety depended on drug indication. In COVID-19 patients, cardiac adverse effects, such as corrected QT interval prolongation, were relatively frequent (0–27.3% and up to 33% if combined with azithromycin), though the risk of torsade de pointes was low. Compared to non-COVID-19 patients, COVID-19 patients experienced a higher frequency of cardiac adverse effects regardless of the regimen used. Dermatological adverse effects affected 0–10% of patients with autoimmune diseases and COVID-19. A broad spectrum of neuropsychiatric adverse effects affected patients treated with CQ for malaria with variable frequencies and some cases were reported in COVID-19 patients. Gastrointestinal adverse effects occurred regardless of drug indication affecting 0–50% of patients. In conclusion, CQ and HCQ are two safe drugs widely used in the treatment of malaria and autoimmune diseases. However, recent findings on their cardiac and neuropsychiatric adverse effects should be considered if these drugs were to be proposed as antivirals again.

Efficacy and safety of hydroxychloroquine in osteoarthritis: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND/AIMS

Conventional disease-modifying anti-rheumatic drugs have been trialed in osteoarthritis (OA). Hydroxychloroquine (HCQ), which has shown its effectiveness in rheumatoid arthritis, has been trialed for the treatment of OA; however, its efficacy and safety remain unclear. This systematic review and meta-analysis evaluate efficacy and safety of HCQ for the treatment of OA.

METHODS

MEDLINE, EMBASE, and Cochrane Central were searched from inception through June 2020. Two reviewers independently screened for randomized controlled trials (RCTs) comparing HCQ with placebo or other active-comparators for the treatment of knee, hand, or hip OA, extracted data, and performed Cochrane risk of bias assessments.

RESULTS

Six RCTs, four in hand OA, two in knee OA, consisting of 842 patients (436 in HCQ arm, 406 in control arm) were included. RCTs were conducted between 2012 and 2020, one each at UK, Netherlands, Germany, Italy, Iran, and Egypt; follow-up period ranged 24 to 52 weeks. High-quality evidence showed no clinically important pain reduction with HCQ compared to placebo/active-control in hand OA (standardized mean difference [SMD], 0.14; 95% confidence interval [CI], -0.20 to 0.48). Effect on pain reduction in knee and hand OA was small and non-significant (SMD, -0.09; 95% CI, -0.44 to 0.25). High-quality evidence showed no improvement in dysfunction with HCQ compared to placebo in hand OA patients (SMD, 0.08; 95% CI, -0.23 to 0.40). Effect on dysfunction improvement in knee and hand OA was modest and statistically non-significant (SMD, -0.20; 95% CI,-0.57 to 0.18). No improvement in quality of life was observed in hand OA.

CONCLUSION

HCQ has no benefit in reducing pain and improving physical function in hand or knee OA patients.

Cost-effectiveness of hydroxychloroquine versus placebo for hand osteoarthritis: economic evaluation of the HERO trial

Background: An economic evaluation alongside the Hydroxychloroquine Effectiveness in Reducing symptoms of hand Osteoarthritis (HERO) trial was undertaken to assess the cost-effectiveness of hydroxychloroquine compared with placebo for symptomatic treatment of hand osteoarthritis for patients with at least moderate hand pain and inadequate response to current therapies.

Methods: A trial-based cost–utility analysis was undertaken from the perspective of the UK National Health Service and Personal Social Services over a 12-month time horizon, using evidence from 248 participants included in the HERO trial, conducted in England. Patient-level data were collected prospectively over a 12-month period, using participant-completed questionnaires and investigator forms, to collect healthcare utilisation, costs and quality-adjusted life years (QALYs) using the EQ-5D-5L. The base-case analysis was conducted on an intention-to-treat basis and used multiple imputation methods to deal with missing data. Results were presented in terms of incremental cost-effectiveness ratios (incremental cost per QALY) and net health benefit, with uncertainty surrounding the findings explored using cost-effectiveness acceptability curves.

Results: The base-case analysis estimated slightly lower costs on average (−£11.80; 95% confidence interval (CI) −£15.60 to −£8.00) and marginally fewer QALYs (−0.0052; 95% CI −0.0057 to −0.0047) for participants in the hydroxychloroquine group versus placebo group at 12 months. The resulting incremental cost-effectiveness ratio of £2,267 per QALY lost indicated that although costs were saved, health-related quality of life was lost. Even assuming symmetrical preferences regarding losses and gains for health benefits, the findings do not fall within the cost-effective region. Similar findings arose for analyses conducted from the societal perspective and using complete cases only.

Conclusions: This economic evaluation indicates that hydroxychloroquine is unlikely to provide a cost-effective pain relief option for improving health-related quality of life in adult patients with moderate-to-severe hand osteoarthritis.

Systematic review and meta-analysis of the safety of chloroquine and hydroxychloroquine from randomized controlled trials on malarial and non-malarial conditions

BACKGROUND

Despite the expectations regarding the effectiveness of chloroquine (CQ) and hydroxychloroquine (HCQ) for coronavirus disease (COVID-19) management, concerns about their adverse events have remained.

OBJECTIVES

The objective of this systematic review was to evaluate the safety of CQ and HCQ from malarial and non-malarial randomized clinical trials (RCTs).

METHODS

The primary outcomes were the frequencies of serious adverse events (SAEs), retinopathy, and cardiac complications. Search strategies were applied to MEDLINE, EMBASE, LILACS, CENTRAL, Scopus, and Trip databases. We used a random-effects model to pool results across studies and Peto's one-step odds ratio (OR) for event rates below 1%. Both-armed zero-event studies were excluded from the meta-analyses. We used the Grading of Recommendations Assessment, Development, and Evaluation system to evaluate the certainty of evidence.

RESULTS

One hundred and six RCTs were included. We found no significant difference between CQ/HCQ and control (placebo or non-CQ/HCQ) in the frequency of SAEs (OR: 0.98, 95% confidence interval [CI]: 0.76-1.26, 33 trials, 15,942 participants, moderate certainty of evidence). However, there was a moderate certainty of evidence that CQ/HCQ increases the incidence of cardiac complications (RR: 1.62, 95% CI: 1.10-2.38, 16 trials, 9908 participants). No clear relationship was observed between CQ/HCQ and retinopathy (OR: 1.63, 95% CI: - 0.4-6.57, 5 trials, 344 participants, very low certainty of evidence).

CONCLUSIONS

CQ and HCQ probably do not increase SAEs, with low frequency of these adverse events on malarial and non-malarial conditions. However, they may increase cardiac complications especially in patients with COVID-19. No clear effect of their use on the incidence of retinopathy was observed.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42020177818.

Prospects for Therapies in Osteoarthritis

Osteoarthritis (OA) is a chronic, debilitating disease affecting millions of people worldwide. Management of OA involves pharmacological and non-pharmacological approaches. Conventional pharmacological treatments have limited efficacy and are associated with a number of side-effects, restricting the number of patients who can use them. New pharmacological therapies for managing OA are required and a number have been developed targeting different tissues in OA: bone and cartilage, synovium and nerves. However, there has been overall limited success. Disease-modifying osteoarthritis drugs (DMOADs) are a putative class of therapies aimed at improving OA structural pathologies and consequent symptoms. Recent DMOAD studies have demonstrated some promising therapies but also provided new considerations for future trials.

Safety of hydroxychloroquine in COVID-19 and other diseases: a systematic review and meta-analysis of 53 randomized trials

INTRODUCTION

Many concerns still exist regarding the safety of hydroxychloroquine (HCQ) in the treatment of Coronavirus Disease 2019 (COVID-19).

OBJECTIVES

The purpose of this study was to evaluate the safety of HCQ in the treatment of COVID-19 and other diseases by performing a systematic review and meta-analysis.

METHODS

Randomized controlled trials (RCTs) reporting the safety of HCQ in PubMed, Embase, and Cochrane Library were retrieved starting from the establishment of the database till June 5, 2020. Literature screening, data extraction, and assessment of risk bias were performed independently by two reviewers.

RESULTS

We identified 53 eligible studies involving 5496 patients. The meta-analysis indicated that the risk of adverse effects (AEs) in the HCQ group was significantly increased compared with that in the control group (RD 0.05, 95%CI, 0.02 to 0.07, P = 0.0002), and the difference was also statistically significant in the COVID-19 subgroup (RD 0.15, 95%CI, 0.07 to 0.23, P = 0.0002) as well as in the subgroup for other diseases (RD 0.03, 95%CI, 0.01 to 0.04, P = 0.003).

CONCLUSIONS

HCQ is associated with a high total risk of AEs compared with the placebo or no intervention in the overall population. Given the small number of COVID-19 participants included, we should be cautious regarding the conclusion stating that HCQ is linked with an increase incidence of AEs in patients with COVID-19, which we hope to confirm in the future through well-designed and larger sample size studies.

Candidate drug replacements for quinacrine in cutaneous lupus erythematosus

Cutaneous lupus erythematosus (CLE) is a disfiguring and potentially disabling disease that causes significant morbidity in patients. Antimalarials are an important class of medication used to treat this disease and have been the first-line systemic therapy since the 1950s. Quinacrine, in particular, is used as an adjuvant therapy to other antimalarials for improved control of CLE. Quinacrine is currently unavailable in the USA, which has taken away an important component of the treatment regimen of patients with CLE. This paper reviews the evidence of available local and systemic therapies in order to assist providers in choosing alternative treatments for patients who previously benefited from quinacrine therapy.

Revisiting hydroxychloroquine and chloroquine for patients with chronic immunity-mediated inflammatory rheumatic diseases

Hydroxychloroquine and chloroquine, also known as antimalarial drugs, are widely used in the treatment of rheumatic diseases and have recently become the focus of attention because of the ongoing COVID-19 pandemic. Rheumatologists have been using antimalarials to manage patients with chronic immune-mediated inflammatory rheumatic diseases for decades. It is an appropriate time to review their immunomodulatory and anti-inflammatory mechanisms impact on disease activity and survival of systemic lupus erythematosus patient, including antiplatelet effect, metabolic and lipid benefits. We also discuss possible adverse effects, adding a practical and comprehensive approach to monitoring rheumatic patients during treatment with these drugs.

Update on novel pharmacological therapies for osteoarthritis

Osteoarthritis (OA) is a chronic painful arthritis with increasing global prevalence. Current management involves non-pharmacological interventions and commonly used pharmacological treatments that generally have limited analgesic efficacy and multiple side effects. New treatments are therefore required to relieve patient symptoms and disease impact. A number of existing pharmacological therapies have been recently trialled in OA. These include extended-release triamcinolone and conventional disease-modifying anti-rheumatic drugs (DMARDs) used in the management of rheumatoid arthritis; generally, DMARDs have not shown a benefit in treating OA. Novel analgesic therapies are in development, including those targeting peripheral pain pathways. Disease-modifying osteoarthritis drugs (DMOADs) target key tissues in the OA pathophysiology process and aim to prevent structural progression; a number of putative DMOADs are in phase II development. There is preliminary evidence of structural improvement with some of these therapies but without concomitant symptom improvement, raising new considerations for future DMOAD trials.

The use of antimalarials in combination with other disease modifying agents in rheumatoid arthritis–the French Experience

A significant proportion of patients with rheumatoid arthritis have an aggressive, severe disease that may contribute to excess mortality. It has been suggested that early, aggressive therapy might improve the prognosis of these patients with active, severe rheumatoid arthritis. Combinations of disease modifying anti-rheumatic drugs including antimalarials are increasingly used in patients with active disease. While several open trials showed encouraging results, some controlled studies gave less support for the use of combination therapy. Ongoing controlled trials of double or triple combination therapy, such as hydroxychloroquine, methotrexate and sulphasalazine, should help define its place in treating patients with rheumatoid arthritis.

Anti-glioma Activity of Dapsone and Its Enhancement by Synthetic Chemical Modification

The sulfone dapsone is an old antibiotic used for the treatment of mycobacterial and protozoal infections. We postulated before that dapsone might possess biological activity exceeding its anti-infectious properties and that it could potentially be repurposed for the treatment of glioma. To test this hypothesis, we treated established and primary cultured glioma cells with dapsone or several dapsone analogues which we previously synthesized (D2-D5) and determined effects on proliferation, anchorage-independent growth and migration. While dapsone and its synthetic analogues D2-D5 displayed only modest anti-proliferative activity, important neoplastic features such as anchorage-independent growth, clonogenic survival and directed migration were significantly inhibited by dapsone treatment. Moreover, dapsone analogues D3, D4 and D5 yielded even enhanced anti-glioma activity against different pro-neoplastic features. Overall these data suggest that dapsone provides activity against glioma which can be further enhanced by molecular modifications. These compounds could potentially serve as a therapeutic adjunct to the treatment of gliomas in a repurposing approach.

Dapsone in dermatology and beyond

Dapsone (4,4′-diaminodiphenylsulfone) is an aniline derivative belonging to the group of synthetic sulfones. In 1937 against the background of sulfonamide era the microbial activity of dapsone has been discovered. Shortly thereafter, the use of dapsone to treat non-pathogen-caused diseases revealed alternate antiinflammatory mechanisms that initially were elucidated by inflammatory animal models. Thus, dapsone clearly has dual functions of both: antimicrobial/antiprotozoal effects and anti-inflammatory features similarly to non-steroidal anti-inflammatory drugs. The latter capabilities primarily were used in treating chronic inflammatory disorders. Dapsone has been investigated predominantly by in vitro methods aiming to get more insights into the effect of dapsone to inflammatory effector cells, cytokines, and/or mediators, such as cellular toxic oxygen metabolism, myoloperoxidase-/halogenid system, adhesion molecules, chemotaxis, membrane-associated phospholipids, prostaglandins, leukotrienes, interleukin-8, tumor necrosis factor α, lymphocyte functions, and tumor growth. Moreover, attention has been paid to mechanisms by which dapsone mediates effects in more complex settings like impact of lifespan, stroke, glioblastoma, or as anticonvulsive agent. Additionally, there are some dermatological investigations in human being using dapsone and its metabolites (e.g., leukotriene B₄-induced chemotaxis, ultraviolet-induced erythema). It could be established that dapsone metabolites by their own have anti-inflammatory properties. Pharmacology and mechanisms of action are determining factors for clinical use of dapsone chiefly in neutrophilic and/or eosinophilic dermatoses and in chronic disorders outside the field of dermatology. The steroid-sparing effect of dapsone is useful for numerous clinical entities. Future avenues of investigations will provide more information on this fascinating and essential agent.

Hydroxychloroquine effectiveness in reducing symptoms of hand osteoarthritis (HERO): study protocol for a randomized controlled trial

Background

Osteoarthritis (OA) is the most common type of arthritis, causing significant joint pain and disability. It is already a major cause of healthcare expenditure and its incidence will further increase with the ageing population. Current treatments for OA have major limitations and new analgesic treatments are needed. Synovitis is prevalent in OA and is associated with pain. Hydroxychloroquine is used in routine practice for treating synovitis in inflammatory arthritides, such as rheumatoid arthritis. We propose that treating patients with symptomatic hand OA with hydroxychloroquine will be a practical and safe treatment to reduce synovitis and pain.

Methods/design

HERO is an investigator-initiated, multicentre, randomized, double-blind, placebo-controlled trial. A total of 252 subjects with symptomatic hand OA will be recruited across primary and secondary care sites in the UK and randomized on a 1:1 basis to active treatment or placebo for 12 months. Daily medication dose will range from 200 to 400 mg according to ideal body weight. The primary endpoint is change in average hand pain during the previous two weeks (measured on a numerical rating scale (NRS)) between baseline and six months. Secondary endpoints include other self-reported pain, function and quality-of-life measures and radiographic structural change at 12 months. A health economics analysis will also be performed. An ultrasound substudy will be conducted to examine baseline levels of synovitis. Linear and logistic regression will be used to compare changes between groups using univariable and multivariable modelling analyses. All analyses will be conducted on an intention-to-treat basis.

Discussion

The HERO trial is designed to examine whether hydroxychloroquine is an effective analgesic treatment for OA and whether it provides any long-term structural benefit. The ultrasound substudy will address whether baseline synovitis is a predictor of therapeutic response. This will potentially provide a new treatment for OA, which could be of particular use in the primary care setting.

Trial registration

ISRCTN91859104.

Autoantibody epitope spreading in the pre-clinical phase predicts progression to rheumatoid arthritis

Rheumatoid arthritis (RA) is a prototypical autoimmune arthritis affecting nearly 1% of the world population and is a significant cause of worldwide disability. Though prior studies have demonstrated the appearance of RA-related autoantibodies years before the onset of clinical RA, the pattern of immunologic events preceding the development of RA remains unclear. To characterize the evolution of the autoantibody response in the preclinical phase of RA, we used a novel multiplex autoantigen array to evaluate development of the anti-citrullinated protein antibodies (ACPA) and to determine if epitope spread correlates with rise in serum cytokines and imminent onset of clinical RA. To do so, we utilized a cohort of 81 patients with clinical RA for whom stored serum was available from 1–12 years prior to disease onset. We evaluated the accumulation of ACPA subtypes over time and correlated this accumulation with elevations in serum cytokines. We then used logistic regression to identify a profile of biomarkers which predicts the imminent onset of clinical RA (defined as within 2 years of testing). We observed a time-dependent expansion of ACPA specificity with the number of ACPA subtypes. At the earliest timepoints, we found autoantibodies targeting several innate immune ligands including citrullinated histones, fibrinogen, and biglycan, thus providing insights into the earliest autoantigen targets and potential mechanisms underlying the onset and development of autoimmunity in RA. Additionally, expansion of the ACPA response strongly predicted elevations in many inflammatory cytokines including TNF-α, IL-6, IL-12p70, and IFN-γ. Thus, we observe that the preclinical phase of RA is characterized by an accumulation of multiple autoantibody specificities reflecting the process of epitope spread. Epitope expansion is closely correlated with the appearance of preclinical inflammation, and we identify a biomarker profile including autoantibodies and cytokines which predicts the imminent onset of clinical arthritis.

Dapsone and sulfones in dermatology: overview and update

In their 60-year history, dapsone and the sulfones have been used as both antibacterial and anti-inflammatory agents. Dapsone has been used successfully to treat a range of dermatologic disorders, most successfully those characterized by abnormal neutrophil and eosinophil accumulation. This article reviews and updates the chemistry, pharmacokinetics, clinical application, mechanism of action, adverse effects, and drug interactions of dapsone and the sulfones in dermatology.

Old and new drugs used in rheumatoid arthritis: a historical perspective. Part 2: the newer drugs and drug strategies

After a 20-year hiatus, drug development for rheumatoid arthritis resumed in the early 1980s with cyclosporine, continuing in the 1990s with minocycline, leflunomide, and the tumor necrosis factor-alpha antagonists, infliximab and etanercept. Unlike the older disease-modifying antirheumatic drugs (apart from the cytotoxics), the newer drugs were designed with strict reference to proven pathophysiology in rheumatoid arthritis and, apart from minocycline, the intended action of these agents is highly likely the explanation for the observed efficacy. The evidence for the evolution of more rational drug development in rheumatoid arthritis has not altered the fact that efficacy versus toxicity still remains the major determinant in the practical use of these agents, as well as in the use of other, experimental agents briefly discussed. Action, efficacy, and toxicity also determine the rational chronologic use of these drugs alone and, in particular, in combination.

Therapy of rheumatoid arthritis: new developments and trends

The medical therapy of rheumatoid arthritis (RA) has been influenced strongly during the past decade by the recognition that many patients develop joint damage within the first year of disease. This observation has motivated rheumatologists to initiate disease-modifying antirheumatic drugs (DMARDs) early in the disease course. This trend has been matched by the increased use of combination DMARD therapy, with the aim to maximize control of the signs and symptoms of RA and limit the development of joint damage. The results from controlled clinical trials generally have supported the concept that early, aggressive treatment with DMARDs is superior to less intensive strategies. In addition, certain DMARD combinations are more effective than the individual components of these regimens, but the evidence is strong for only a few DMARD combinations such as methotrexate and cyclosporine A. Three new drugs have been recently approved for the treatment of RA. Celecoxib, a selective cyclooxygenase-2 inhibitor, has similar clinical efficacy as conventional nonsteroidal anti-inflammatory drugs, and in short-term studies causes no more gastric and duodenal ulcers and erosions than patients treated with placebo. Treatment with leflunomide, an inhibitor of pyrimidine synthesis, has been shown in controlled clinical trials to produce significant clinical improvement in 50% to 60% of patients with RA and delay radiologic progression of disease. The era of biologic therapy has dawned with the apparent success of tumor necrosis factor (TNF)-alpha blockade using etanercept, a recombinant TNF receptor:Fc fusion protein, and infliximab, a chimeric anti-TNF monoclonal antibody. These new agents expand our treatment options in RA and should lead to innovative and more effective treatment approaches.

Is there a role for antibiotics in the treatment of patients with rheumatoid arthritis?

Despite many advances in the understanding and treatment of rheumatoid arthritis, its pathophysiology remains incompletely understood. An infectious aetiology of rheumatoid arthritis has long been postulated but, even though many continue to believe that there is a 'triggering agent for rheumatoid arthritis', none has been identified. Currently, both sulfasalazine and minocycline have been shown to be effective treatments for rheumatoid arthritis and are being used increasingly. In the case of minocycline, it appears that its ability to inhibit metalloproteases is an important characteristic that may account for some or part of its action against rheumatoid arthritis. Whether the antibacterial effects of these drugs or others are important in the treatment of rheumatoid arthritis continues to be investigated.

Dapsone in rheumatoid arthritis

Dapsone, a synthetic sulfone with chemical similarities to sulfapyridine, has been used for a number of years to treat leprosy and dermatitis herpetiformis. Recently, a number of prospective, randomized, double-blind trials have shown their success in the management of rheumatoid arthritis, with dapsone being superior to placebo and comparable to chloroquine and hydroxychloroquine. Its mode of anti-inflammatory actions in rheumatoid arthritis is not clearly understood, but modulation of neutrophil activity or inhibition of neutrophil inflammatory product formation or release appear to play a role. The major limiting side effect is hemolytic anemia, which may be mitigated through careful patient selection, conservative drug dosing, close monitoring, and possibly, concurrent administration of antioxidants or cytochrome P450 inhibitors. Methemoglobinemia is another common finding among patients receiving dapsone therapy, but rarely does it result in prominent symptoms other than transient pallor. Less common adverse events to dapsone include the idiosyncratic reactions of leukopenia and agranulocytosis, cutaneous eruptions, peripheral neuropathy, psychosis, toxic hepatitis, cholestatic jaundice, nephrotic syndrome, renal papillary necrosis, severe hypoalbuminemia without proteinuria, an infectious mononucleosis-like syndrome, and minor neurological and gastrointestinal complaints. In this report, two patients with advanced rheumatoid arthritis, who were safely and effectively treated with dapsone after failure with other second-line agents, are described and the literature is reviewed. We suggest that dapsone is an effective second-line agent in the treatment of rheumatoid arthritis.

Antimicrobial therapy for rheumatoid arthritis

New interest in the use of antibiotics in the treatment of arthritis was stimulated by two factors: (1) observations that, in some forms of chronic arthritis, microbial antigens persist in the synovial membrane, and (2) the increasing knowledge of the anti-inflammatory and immunosuppressive effects of antibiotics. Recently, several published controlled studies reported a beneficial effect of tetracyclines on RA and reactive arthritis. Whether the anti-arthritic activity of the tetracyclines investigated is mediated by the antimicrobial, anti-inflammatory or immunomodulatory properties remains to be determined. It may be concluded from these studies that tetracyclines have a beneficial effect on RA, especially when laboratory parameters are considered. The effect on the clinical parameters is not unequivocal. The adverse effects seem to be mild but the long-term efficacy and safety of tetracyclines as disease-modifying antirheumatic drugs remain to be demonstrated.