Antimalarials in rheumatology: efficacy and safety

Safety of treatment with chloroquine and hydroxychloroquine: A ten-year systematic review and meta-analysis

OBJECTIVE

To estimate the incidence rate ratio (IRR) of adverse events (AE) in chloroquine or hydroxychloroquine users.

METHODS

We systematically reviewed randomized controlled trials (RCTs), using MEDLINE (2010-2020) and EMBASE (2010-2020) databases, reporting AE in chloroquine or hydroxychloroquine users during treatment for lupus, rheumatoid arthritis, malaria and COVID-19. The protocol for this systematic review is registered at the PROSPERO database (CRD42020197938). The quality of the included studies was assessed using the Cochrane risk-of-Bias tool and relevant data were extracted though a customized data collection form, independently, by two authors. The IRR of AE was estimated using a random-effect model meta-analysis and heterogeneity was evaluated by T² and I². Subgroup analysis was performed, and publication bias was assessed by funnel-plot.

RESULTS

Forty-six RCTs met our eligibility criteria and were included in our analysis (23132 patients). There was not a single death attributed to chloroquine or hydroxychloroquine use in the included RCTs. The IRR of general AE during antimalarial use was 1.15 [CI 95% 1.01-1.31]. COVID-19 patients treated with either antimalarial presented an 83% and 165% higher risk of developing general and gastrointestinal AE, respectively, in comparison with controls. The use of antimalarial increased the risk of developing dermatological AE by 92% in malarial studies and reduced by 65% in lupus studies. We did not find a significatively higher risk of cardiovascular nor ophthalmological AE in antimalarial users.

CONCLUSIONS

Our data reinforces that chloroquine and hydroxychloroquine have a good safety profile though caution is advised when using higher than usual doses in hospitalized COVID-19 patients.

Precision medicine in the care of rheumatoid arthritis: Focus on prediction and prevention of future clinically-apparent disease

There is an emerging understanding that an individual's risk for future rheumatoid arthritis (RA) can be determined using a combination of factors while they are still in a state where clinically-apparent inflammatory arthritis (IA) is not yet present. Indeed, this concept has underpinned several completed and ongoing prevention trials in RA. Importantly, risk factors can be divided into modifiable (e.g. smoking, exercise, dental care and diet) and non-modifiable factors (e.g. genetics, sex, age). In addition, there are now several biomarkers including autoantibodies, inflammatory markers and imaging techniques that are highly predictive of future clinically-apparent IA/RA. Although none of the prevention studies have yet provided major breakthroughs, several of them have provided valuable insights that can help to improve the design of future clinical trials and enable RA prevention. In aggregate, these findings suggest that the most accurate disease prediction models will require the combination of demographic and clinical information, biomarkers and potentially medical imaging data to identify individuals for intervention. This review summarizes some of the key aspects around precision medicine in RA with special focus on disease prediction and prevention.

The Efficacy of Antimalarials in Systemic Lupus Erythematosus

The use of antimalarial drugs to treat systemic lupus erythematosus (SLE) is reviewed regarding their value in SLE of mild-to-moderate disease activity, as corticosteroid-sparing agents, and as an adjunctive therapy in severe SLE. A retrospective controlled study of a variety of antimalarials and a randomized discontinuation trial of hydroxychloroquine support the considerable clinical belief that antimalarials are of benefit in mild-to-moderate SLE. Anecdotal reports and the opinion of experienced clinicians suggest that antimalarials permit the use of lower doses of corticosteroids. No controlled study has confirmed a corticosteroid-sparing role for antimalarials, although no controlled study has been conducted specifically to address this hypothesis. The data on antimalarials in severe SLE are scant.

Antimalarials are likely effective in at least a subgroup of SLE patients with mild-to-moderate disease activity. Whether these agents are corticosteroid sparing and prevent severe disease exacerbations is unproven. Given the low toxicity of antimalarials, further studies are clearly warranted.

Factors associated with chloroquine-induced retinopathy in rheumatic diseases

Antimalarials are very useful drugs in the treatment of various rheumatic diseases. One of their main side effects is ocular toxicity, specifically retinopathy. Our objective was to identify risk factors associated with chloroquine retinopathy. A single, trained evaluator reviewed patient records with rheumatic diseases. They were taking chloroquine and identified by the ophthalmologydepartment as having retinopathy during their routine eye evaluation. These cases were classified according to clinical evaluation, visual fields and fluorangiographic study. Up to four controls were selected for each case, matched by age, gender, diagnosisand similar time on chloroquine.In all, 34 variableswere studied, among these: weight, age, disease duration, keratopathy, total cumulative dose (TCD), mean daily dose (MDD), lean body weight adjusted daily dose (LBWDD) and laboratory tests. Descriptive and inferential statistics comparing cases and controls in all patients and subgroup analysis were carried out. Significance was set at the 0.05 level. Odds ratio and 95% confidence intervals were calculated. Sixteen cases of chloroquine retinopathy were identified, eight patients with rheumatoid arthritis (RA), seven with systemic lupus erythematosus (SLE) and one with dermatomyositis. All were female. Mean age was 47.3 + 12.2 years; weight 59.5 + 10.7 kg; disease duration 12.8 + 6.0 years; time on chloroquine 54.1 + 27.8 (min-max: 30-197) months. There was a significant difference in the following variables in all patients: MDD 212.3 + 52.6 versus 170 + 51.3, p 0.009; and LBWDD 5 + 1 versus 4.2 + 1.5, p 0.03, for cases and controls, respectively. In subgroup analysis the MDD remained significantly different (235.5 + 45.8 versus 169.7 + 46.l, p 0.004) only in RA, whereas LBWDD was different both in SLE and RA. Keratopathy increased the risk for retinopathy: OR, 95% CI: 5, 1.4-l7.6, p 0.01. In conclusion, in accordance with previous studies, the MDD, LBWDD and keratopathy were risk factors associated with chloroquine retinopathy. Periodic ophthalmologic evaluations are mandatory.

Therapy and pharmacological properties of hydroxychloroquine and chloroquine in treatment of systemic lupus erythematosus, rheumatoid arthritis and related diseases

OBJECTIVES

This review examines the pharmacokinetics, modes of action and therapeutic properties of the anti-malarial drugs, hydroxychloroquine (HCQ) and chloroquine (CQ), in the treatment of systemic lupus erythematosus (SLE), rheumatoid arthritis (RA) and related conditions, as well as osteoarthritis (OA).

KEY FINDINGS

Both HCQ and CQ have historically been employed successfully for the treatment of SLE and RA for over 70 years. HCQ has been used extensively for SLE where it has a good reputation for controlling the dermatological complications in SLE. It has also been reported to effectively control the symptoms of Sjøgren's syndrome, as well as preventing thrombosis in phospholipid antibody (aPL) syndrome. In RA and SLE, HCQ is preferred because of the lower incidence of gastrointestinal adverse reactions compared with CQ and it might have a lower risk of ocular adverse reactions. There is increasing evidence that HCQ may reduce atherosclerosis and risks of cardiovascular disease in rheumatic patients. Both HCQ and CQ have been shown to improve glycaemia and reduce the risks of type II diabetes mellitus. Although both HCQ and CQ are effective in low-moderate RA, HCQ is now preferred as part of combination therapy for more severe disease. The advantages of combination therapy are that the doses of the individual drugs may be lowered so reducing adverse reactions. Both HCQ and CQ are diastereoisomers, have basic properties and are given as the sulphate and phosphate salts. While being relatively well absorbed orally and with good bioavailability, they have long and variable plasma terminal elimination half-lives (approximately 40-60 days). This reflects their high volume of distribution, V D (HCQ 44,000L; CQ 65,000L) which extends into aqueous compartments, long mean residence time (HCQ 1300 h; CQ 900 h) and with about half the drugs (metabolites) undergoing renal clearance. The strong binding to melanin reflects the ocular injury and dermatological properties of these drugs. The consensus is that the occurrence of ocular adverse reactions can be minimised by close attention to the dose (which should be set on a body weight basis) with regular (e.g. quarterly) retinal examination. Although HCQ and CQ can pass through the placenta, the use of these drugs during pregnancy does not appear to risk harm to the baby and might be beneficial to the mother with SLE and her child by controlling the SLE disease activity, which is known to be an important factor affecting pregnancy outcome. The modes of action of HCQ and CQ in these arthritides represent somewhat of an enigma. Undoubtedly, these drugs have multiple actions related, in part, their ability to accumulate in lysosomes and autophagosomes of phagocytic cells as well as affecting MHC Class II expression and antigen presentation; actions of the production of pro-inflammatory cytokines [e.g. interleukin-1 (IL-1) tumour necrosis factor-α (TNFα)]; control of toll-like receptor-9 activation; and leucocyte generation of reactive oxygen species (ROS); i.e. antioxidant activity. The actions of these drugs on T and B cells are less clear but may depend on these leucocyte-mediated actions. Anti-malarials also protect against cytokine-mediated cartilage resorption. This and other actions may underlie the potential benefits in treating OA. The exact relationships of these various actions, mostly determined in vitro, have not been specifically defined in vivo or ex vivo in relation to clinical efficacy.

OUTCOMES

HCQ and CQ have a good reputation for being effective and relatively safe treatments in SLE, mild-moderate RA and Sjøgren's syndrome. There is need for (a) more information on their mode of action in relation to the control of these diseases, (b) scope for developing formulations that have improved pharmacokinetic and therapeutic properties and safety, and (c) further exploring their use in drug combinations not only with other disease modifying agents but also with biologics.

Pharmacology of Chloroquine and Hydroxychloroquine

The 4-aminoquinolines are weak bases that are completely absorbed from the gastrointestinal tract, sequestered in peripheral tissues, metabolized in the liver to pharmacologically active by-products, and excreted via the kidneys and the feces. The parent drugs and metabolites are excreted with a half-life of elimination of approximately 40 days. However, slow release from sequestered stores of the drugs means that after discontinuation, they continue to be released into the plasma for years. Correct dosing is based on the ideal body weight of the patient, which depends on height. The 4AQs diminish autoimmunity without compromising immunity to infections.

Emerging role of endosomal toll-like receptors in rheumatoid arthritis

Toll-like receptors (TLRs) and their downstream signaling pathways have been comprehensively characterized in innate immunity. In addition to this function, these receptors have also been suggested to be involved in the pathogenesis of many autoimmune diseases, including rheumatoid arthritis (RA). Murine in vivo models and human in vitro tissue models of RA have provided a wealth of information on the potential activity of TLRs and components of the downstream signaling pathways. Whilst most early work investigated the cell surface TLRs, more recently the focus has moved to the endosomal TLRs 3, 7, 8, and 9. These receptors recognize self and foreign double-stranded RNA and single-stranded RNA and DNA. The development of therapeutics to inhibit the endosomal TLRs or components of their signaling cascades may represent a way to target inflammation upstream of cytokine production. This may allow for greater specificity than existing therapies including cytokine blockade. Here, we review the current information suggesting a role for the endosomal TLRs in RA pathogenesis and the efforts to target these receptors therapeutically.

Hydroxychloroquine cardiotoxicity presenting as a rapidly evolving biventricular cardiomyopathy: key diagnostic features and literature review

Cardiotoxicity is a rare but serious complication of hydroxychloroquine, a 4-aminoquinoline increasingly used in the treatment of rheumatological disorders. We describe typical clinical, echocardiographic, and histological features of this rare condition according to the currently available literature, illustrated with a recent new biopsy-proven case of hydroxychloroquine cardiotoxicity in a 52-year-old female with rheumatoid arthritis. Presentation in this case was of a rapidly progressive decompensated biventricular cardiomyopathy associated with recurrent biomarker elevations, conduction system disease, and possibly neuromyotoxicity. Death occurred suddenly 2 months after diagnosis despite drug discontinuation and clinical improvement. The potential role of cardiac magnetic resonance delayed gadolinium enhancement imaging in the prognosis of this toxic cardiomyopathy is also introduced. This case-based literature review highlights that, although rare, hydroxychloroquine cardiotoxicity can be fatal, particularly if irreversible histopathological changes have occurred prior to drug discontinuation. Given this, regular screening with 12-lead electrocardiography and transthoracic echocardiography to detect conduction system disease and/or biventricular morphological or functional changes should be considered in hydroxychloroquine-treated patients in addition to recommended ophthalmological screening.

Ultrasonographic evaluation of the muscle architecture in patients with systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a multi-system chronic inflammatory disease with a broad spectrum of clinical and serological manifestations. Although clinical evidence of proximal skeletal muscle involvement is not rare in patients with SLE, there is no knowledge about the effects of SLE on the macroscopic structural parameters of the muscles. Therefore, in this study, we aimed to explore the muscle strength and structure of SLE patients using isokinetic testing and ultrasonographic imaging. Thirty-one SLE patients (5 men, 26 women) with a mean age of 38.61 ± 10.68 years and mean disease duration of 3.71 ± 3.23 years without any previous history of myositis and 31 age- and sex-matched healthy subjects were enrolled. Demographic and clinical characteristics of the patients were recorded. Ultrasonographic evaluations were performed with a 7- to 12-MHz linear probe from vastus lateralis and gastrocnemius muscles of the nondominant extremity. Measurements included muscle thickness, pennation angle, and fascicule length. Isokinetic nondominant knee muscle strength tests were performed at 60 and 180°/s. We found that muscle thickness, pennation angle, and fascicle length of vastus lateralis muscles were increased in patients with SLE in comparison to control subjects (p < 0.001, p = 0.007, and p = 0.217, respectively). On the other hand, the measurements pertaining to the gastrocnemius muscles were found to be similar between the two groups. We observed that all isokinetic knee muscle strength values were decreased in SLE patients, and knee strength values were found to be negatively correlated with age and positively correlated with height (all p < 0.01). We found that the structural and strength changes were seen in the proximal muscles of SLE patients. Pathophysiology and clinical relevance of these changes need to be further investigated.

Treatment of cutaneous lupus erythematosus

In patients with cutaneous lupus erythematosus (CLE) and mild skin involvement, local therapy consisting of topically applied pharmacological agents, e.g., topical/intralesional steroids, may be sufficient. Recent reports have also shown efficacy of topical calcineurin inhibitors in patients with CLE, particularly on the face. Special attention receives consistent sun protection through photoresistant clothing and application of light-shielding substances with highly potent chemical or physical UVA- and UVB-protective filters. These substances should be applied in sufficient amount (ca. 2 mg/cm(2)) at least 20-30 minutes before sun exposure in order to avoid induction and exacerbation of cutaneous lesions. The mainstay of treatment for disfiguring and widespread skin manifestations in patients with CLE, irrespective of the subtype of the disease, is antimalarial agents. Our understanding of the use of combinations of antimalarials and proper dosing according to the ideal bodyweight limits problems with toxicity. Further therapies, such as methotrexate, or retinoids, dapsone, mycophenolate mofetil, and thalidomide in selected cases, can be helpful for patients with resistant disease; however, side effects need to be taken into consideration. Recent advances in biotechnology resulted in the development of novel systemic agents, but randomized controlled trials are necessary for the approval of new therapeutic strategies in CLE.

Use of antimalarials in dermatology

The antimalarials chloroquine and hydroxychloroquine have been used for the treatment of inflammatory diseases for more than 60 years. Even today new indications evolve due to the complex mode of action of these compounds. Due to the fear of side effects, especially irreversible retinopathy, their use is often limited. These side-effects, however, are a consequence of excessive daily dosages. An effective, safe therapy needs correct dosing, i. e. adherence to maximal daily dosages of 3.5(-4) mg chloroquine or 6(-6.5) mg hydroxychloroquine per kilogram ideal body weight. If the actual body weight is lower than the ideal body weight, this actual weight is used for the calculation of the dosage. Observing these limits allows a rather safe therapy of the diseases like lupus erythematosus, REM syndrome, porphyria cutanea tarda (2 × 125 mg chloroquine/week), cutaneous sarcoidosis and dermatomyositis. If standard therapies fail, then antimalarials can be tried to treat Sjögren syndrome, granuloma annulare or erosive lichen planus. If therapy fails, either can be combined with quinacrine to increase their effectiveness. Chloroquine and hydroxychloroquine are indispensable and well-tolerated essential drugs in dermatology and especially suited as part of a combination scheme, for example with corticosteroids, as they act synergistically and reduce side-effects.

Antimalarial myopathy: an underdiagnosed complication? Prospective longitudinal study of 119 patients

OBJECTIVES

To evaluate the prevalence and incidence of antimalarial myopathy in patients with rheumatic diseases treated with antimalarial drugs.

METHODS

Over a three year period, all patients with rheumatic diseases who were taking antimalarial drugs were studied. Serum muscle enzymes were assessed at the time of inclusion and every six months thereafter. Muscle strength, electromyography (EMG), and muscle biopsy were assessed in patients with a persistent muscle enzyme disturbances.

RESULTS

119 patients were included (111 chloroquine, eight hydroxychloroquine). Of these, 22 (18.5%) had a persistent muscle enzyme disturbance: lactate dehydrogenase 19/22 (86%); creatine kinase 7/22 (32%), and aldolase 3/22 (14%). Findings of antimalarial myopathy were detected in 3/15 biopsied patients (20%) by light microscopy and in all 15 by electron microscopy. Eleven patients had myopathy at the time of inclusion (prevalence 9.2%) and four patients developed muscle injury during follow up (annual incidence 1.2%). Muscle weakness was observed in 8 of 15 patients with biopsy proven myopathy, giving a prevalence of clinical antimalarial myopathy of 6.7%. All these patients also had a myopathic pattern on electromyography.

CONCLUSIONS

The prevalence of antimalarial myopathy is higher than previously recognised when muscle enzyme determination is used as a screening method. When a persistent muscle enzyme disturbance is observed, clinical and electromyographic studies should be undertaken periodically to detect the development of clinical myopathy. In cases of clinical myopathy, an anatomical-pathological tissue study, including an ultrastructural study, is mandatory to confirm the diagnosis.

Systemic lupus erythematosus in three ethnic groups: XVI. Association of hydroxychloroquine use with reduced risk of damage accrual

OBJECTIVE

To examine whether hydroxychloroquine (HCQ) usage is associated with a reduced risk of damage accrual in patients with systemic lupus erythematosus (SLE).

METHODS

Patients (n = 518) meeting the American College of Rheumatology criteria for diagnosis of SLE and with </=5 years disease duration at study entry were followed up annually. Socioeconomic, demographic, clinical, and serologic manifestations as well as disease activity (by the Systemic Lupus Activity Measure [SLAM]) and damage (by the Systemic Lupus International Collaborating Clinics damage index [SDI]) were measured. Propensity scores were calculated to adjust for confounding factors affecting treatment assignment. A Cox proportional hazards model was used to compare the risk of developing new damage according to HCQ use at enrollment into the study.

RESULTS

Fifty-six percent of the patients were treated with HCQ at the time of study enrollment. Patients who were not treated with HCQ on enrollment had higher SLAM and SDI scores than patients who were treated. Untreated patients were significantly more likely to have major organ involvement such as renal disease (P < 0.0001) or central nervous system disease (P < 0.0025). Results of unadjusted analysis suggested that treated patients were less likely to accrue damage (hazard ratio [HR] 0.68). With adjustment for differences in treatment assignment, HCQ usage was still associated with a reduced risk of developing new damage, with an HR of 0.68 (95% confidence interval [95% CI] 0.53-0.93) (P = 0.014). With adjustment for differences in treatment assignment, HCQ usage was still associated with a reduced risk of developing new damage (HR 0.73 [95% CI 0.52-1.00]) (P = 0.05). However, patients receiving HCQ who had no damage at study entry had a statistically significant decrease in the risk of damage accrual (HR 0.55 [95% CI 0.34-0.87]) (P = 0.0111), whereas those receiving HCQ who had damage at study entry did not (HR 1.106 [95% CI 0.70-1.74]) (P = 0.6630).

CONCLUSION

These findings indicate that, after adjustment for propensity to receive HCQ, HCQ usage is independently associated with a reduced risk of damage accrual in SLE patients who had not yet accrued damage at the time of treatment initiation.

Optimal use of antimalarials in treating cutaneous lupus erythematosus

Antimalarials have been used to treat cutaneous and systemic lupus erythematosus (LE) for decades. Although controlled studies comparing the efficacy of antimalarials versus placebo and other treatments are generally lacking, many case reports and series support the therapeutic efficacy of these agents in treating both LE-specific and -nonspecific skin lesions. Currently, the two most frequently used antimalarial agents are chloroquine and hydroxychloroquine. There may be a delay of weeks to months in the onset of therapeutic effects of antimalarials when treating LE. Smoking appears to inhibit the therapeutic efficacy of antimalarials when treating cutaneous LE. Antimalarials have been associated with a number of potentially serious adverse effects, including irreversible loss of vision. The aim of this review is to discuss the many facets of antimalarials that will help clinicians optimally utilize these agents when treating cutaneous LE.

Hydroxychloroquine cardiotoxicity in systemic lupus erythematosus: a report of 2 cases and review of the literature

BACKGROUND

Hydroxychloroquine (HCQ) is extensively used in the long-term treatment of systemic lupus erythematosus (SLE). Although considered by clinicians to be relatively safe, serious side effects have been documented in the literature. Retinotoxicity has received the most attention, whereas neuromyotoxicity and cardiotoxicity have been described in isolated case reports. We present 2 cases of potential cardiotoxicity occurring in patients with SLE while receiving long-term HCQ therapy.

OBJECTIVE

To review the incidence, presentation, and mechanism of serious antimalarial toxicity, and to discuss the impact of HCQ on cardiac health in SLE.

METHODS

The authors reviewed the English-language literature from 1948 to December 2002 using Medline databases.

RESULTS

In addition to our patients, there are 2 published cases of biopsy-proven HCQ cardiotoxicity in the English-language literature. Both occurred in patients with SLE. The literature indicates that antimalarial cardiotoxicity may be of particular importance in patients with SLE given their already increased cardiac risk due to primary heart disease and accelerated atherosclerosis. Endomyocardial biopsy reveals a constellation of findings including vacuolar myopathy, myeloid bodies, and curvilinear bodies.

CONCLUSIONS

As HCQ use among SLE patients increases, clinicians should be alert to the possibility of antimalarial cardiotoxicity. The potential severity and reversibility of this complication underscore the importance of timely diagnosis. The cases presented here, one with biopsy and one without, illustrate the utility of endomyocardial biopsy in HCQ-treated SLE patients with cardiac complaints to ensure accurate diagnosis and appropriate management.

In vitro metabolism of chloroquine: identification of CYP2C8, CYP3A4, and CYP2D6 as the main isoforms catalyzing N-desethylchloroquine formation

In humans, the antimalarial drug chloroquine (CQ) is metabolized into one major metabolite, N-desethylchloroquine (DCQ). Using human liver microsomes (HLM) and recombinant human cytochrome P450 (P450), we performed studies to identify the P450 isoform(s) involved in the N-desethylation of CQ. In HLM incubated with CQ, only DCQ could be detected. Apparent Km and Vmax values (mean +/- S.D.) for metabolite formation were 444 +/- 121 microM and 617 +/- 128 pmol/min/mg protein, respectively. In microsomes from a panel of 16 human livers phenotyped for 10 different P450 isoforms, DCQ formation was highly correlated with testosterone 6beta-hydroxylation (r = 0.80; p < 0.001), a CYP3A-mediated reaction, and CYP2C8-mediated paclitaxel alpha-hydroxylation (r = 0.82; p < 0.001). CQ N-desethylation was diminished when coincubated with quercetin (20-40% inhibition), ketoconazole, or troleandomycin (20-30% inhibition) and was strongly inhibited (80% inhibition) by a combination of ketoconazole and quercetin, which further corroborates the contribution of CYP2C8 and CYP3As. Of 10 cDNA-expressed human P450s examined, only CYP1A1, CYP2D6, CYP3A4, and CYP2C8 produced DCQ. CYP2C8 and CYP3A4 constituted low-affinity/high-capacity systems, whereas CYP2D6 was associated with higher affinity but a significantly lower capacity. This property may explain the ability of CQ to inhibit CYP2D6-mediated metabolism in vitro and in vivo. At therapeutically relevant concentrations ( approximately 100 microM CQ in the liver), CYP2C8, CYP3A4, and, to a much lesser extent, CYP2D6 are expected to account for most of the CQ N-desethylation.

Medical management of children with juvenile rheumatoid arthritis

One of the most important and changing areas of research in paediatric rheumatology is the optimum approach to the treatment of children with chronic arthritis. Until recently all medications for children with arthritis were nonspecific in terms of our understanding, albeit poor, of the pathogenesis of these diseases. Of current therapies, low dose, once-a-week methotrexate has emerged as the therapeutic agent of choice for children who fail to respond adequately to administration of a nonsteroidal anti-inflammatory drug. Thereby, it has displaced the more traditional slower acting anti-rheumatic drugs, although one or more of them are often combined with methotrexate in the polypharmaceutical approach to childhood arthritis. Better and more specific agents are needed, especially for systemic onset disease, unremitting polyarticular involvement, and certain complications such as resistant chronic uveitis. At this time the introduction of the cyclo-oxygenase 2 inhibitors and etanercept (soluble tumour necrosis factoralpha.p75 fusion protein) may herald an era of more specific and effective therapy.

Long-term effectiveness of antimalarial drugs in rheumatic diseases

OBJECTIVE

The purpose of this study was to compare the long-term effectiveness between chloroquine (CQ) and hydroxychloroquine (HCQ).

METHODS

Medical charts of all patients seen by eight rheumatologists practising in two tertiary care centres and starting antimalarial treatment between January 1985 and December 1993 were reviewed. Patient characteristics, disease, and treatment information were collected. The main outcome measures were the cause of and the time to the discontinuation of antimalarial drugs resulting from all causes, principally toxicity or inefficacy, or both. Bivariate analysis including t tests and chi 2 tests were used to assess differences between means and proportions respectively. Survival curves were evaluated using the Kaplan-Meier method. Multivariate analysis (Cox regression) was used to adjust for potential confounders.

RESULTS

After all medical records were reviewed, 1042 eligible cases were identified. From these, 940 (90%) had usable information and they represent the cohort. Five hundred and fifty eight had rheumatoid arthritis, 178 had systemic lupus erythematosus, 127 had palindromic arthritis, and 77 had other diagnoses. Fifty seven per cent of the patients received CQ and 43% HCQ. The proportion of patients with side effects taking HCQ and CQ was 15% and 28% respectively (p = 0.001). Using Cox regression model to adjust for age at the onset of antimalarial treatment, physician differences, sex, disease type, disease duration before treatment, and rank selection, there were no differences in the hazard ratio (HR) for overall discontinuations between CQ and HCQ. While the HR for discontinuations because of toxicity was lower for HCQ (HR = 0.6, 95% CI 0.4, 0.9), the HR for discontinuations because of inefficacy was significantly higher for HCQ (HR = 1.4, 95% CI 1.1, 1.9).

CONCLUSIONS

After adjusting for time and several confounders HCQ was less toxic but less effective than CQ. Only one case of probable/possible retinopathy was found. Therefore, we propose a careful baseline ophthalmological evaluation by an expert and then one or every two years if proper doses are used.

Sarcoidosis of the paranasal sinuses treated with hydroxychloroquine

A case of sarcoidosis of the paranasal sinuses is reported. Biopsies of the sinus mucosa showed typical noncaseating granulomas. Hydroxychloroquine, which is known to be active on the cutaneous form of sarcoidosis, was used here with success and is proposed as an effective alternative to high-dose systemic steroids.

Clinical pharmacokinetics and metabolism of chloroquine. Focus on recent advancements

This paper presents the current state of knowledge on chloroquine disposition, with special emphasis on stereoselectivity and microsomal metabolism. In addition, the impact of the patient's physiopathological status and ethnic origin on chloroquine pharmacokinetics is discussed. In humans, chloroquine concentrations decline multiexponentially. The drug is extensively distributed, with a volume of distribution of 200 to 800 L/kg when calculated from plasma concentrations and 200 L/kg when estimated from whole blood data (concentrations being 5 to 10 times higher). Chloroquine is 60% bound to plasma proteins and equally cleared by the kidney and liver. Following administration chloroquine is rapidly dealkylated via cytochrome P450 enzymes (CYP) into the pharmacologically active desethylchloroquine and bisdesethylchloroquine. Desethylchloroquine and bisdesethylchloroquine concentrations reach 40 and 10% of chloroquine concentrations, respectively; both chloroquine and desethylchloroquine concentrations decline slowly, with elimination half-lives of 20 to 60 days. Both parent drug and metabolite can be detected in urine months after a single dose. In vitro and in vivo, chloroquine and desethylchloroquine competitively inhibit CYP2D1/6-mediated reactions. Limited in vitro studies and preliminary data from clinical experiments and observations point to CYP3A and CYP2D6 as the 2 major isoforms affected by or involved in chloroquine metabolism. In vitro efficacy studies did not detect any difference in potency between chloroquine enantiomers but, in vivo in rats, S(+)-chloroquine had a lower dose that elicited 50% of the maximal effect (ED950) than that of R(-)-chloroquine. Stereoselectivity in chloroquine body disposition could be responsible for this discrepancy. Chloroquine binding to plasma proteins is stereoselective, favouring S(+)-chloroquine (67% vs 35% for the R-enantiomer). Hence, unbound plasma concentrations are higher for R(-)-chloroquine. Following separate administration of the individual enantiomers, R(-)-chloroquine reached higher and more sustained blood concentrations. The shorter half-life of S(+)-chloroquine appears secondary to its faster clearance. Blood concentrations of the S(+)-forms of desethylchloroquine always exceeded those of the R(-)-forms, pointing to a preferential metabolism of S(+)-chloroquine.

Disease-modifying antirheumatic drugs. Potential effects in older patients

Disease-modifying antirheumatic drugs (DMARDs) are frequently used in rheumatoid arthritis. A number of physiological changes occur in the elderly which may modify the use of these medications. The most commonly used DMARDs are antimalarial drugs (particularly hydroxychloroquine), sulfasalazine and methotrexate. The principal mechanism of action of the antimalarials relates to the fact that they change intracellular pH, which downregulates numerous immune functions. Hydroxychloroquine is metabolised to 3 metabolites and has a very low clearance. It is moderately effective in dosages up to 6.4 mg/kg/day. While it is not the most effective of the DMARDs, it is the least toxic. Sulfasalazine is a prodrug which is enzymatically split in the bowel to form sulfapyridine (the principal active metabolite) and 5-aminosalicylic acid. The metabolism of sulfasalazine is complex and, to some extent, genetically determined. The mechanism of action of the drug is not well understood, but involves decreased production of cytokines and decreased proliferative response of lymphocytes. It may slow the rate of bony damage associated with rheumatoid arthritis. Nearly 50% of the patients who are prescribed sulfasalazine continue to receive the drug for up to 4 years. Sulfasalazine is not as well tolerated as hydroxychloroquine. Gastrointestinal toxicity, in particular, seems to be a problem in elderly patients taking this medication. Methotrexate is presently the most popular of the DMARDs for the treatment of rheumatoid arthritis. Methotrexate inhibits dihydrofolate reductase and adenosine release and has a secondary effect on cytokines and polymorphonuclear chemotaxis. It is highly metabolised within cells and remains there for prolonged periods. Up to 70% of patients who are prescribed methotrexate continue treatment for 5 years. Methotrexate treatment is associated with gastrointestinal, hepatic, cutaneous and, possibly, pulmonary adverse effects. The use of azathioprine, penicillamine and gold compounds is briefly reviewed in this article. Elderly patients have an increased incidence of rashes when using penicillamine, relative to young patients. There are no age-related differences in the efficacy and tolerability of azathioprine or gold therapy. The poor absorption and renal toxicity associated with cyclosporin, the new 'salvage' therapy in rheumatoid arthritis, make it generally unsuitable for use in the elderly, except under specialists' supervision.

Prednisone treatment of elderly-onset rheumatoid arthritis. Disease activity and bone mass in comparison with chloroquine treatment

OBJECTIVE

Prednisone is frequently used in the treatment of elderly-onset rheumatoid arthritis (RA), but the balance between efficacy and toxicity, including the effect on bone mass, has not been investigated in long-term studies. This prospective, randomized study was undertaken to compare disease activity and bone mass during long-term treatment with prednisone versus chloroquine in this patient population.

METHODS

Patients with active RA diagnosed at age > or = 60 were randomized to receive prednisone (15 mg/day for 1 month, with the dosage tapered as low as possible thereafter) (n = 28) or chloroquine (n = 28). Patients who did not show a response received other second-line drugs as an adjunct to prednisone or as a replacement for chloroquine. Bone mass was measured by dual-energy x-ray absorptiometry. The study duration was 2 years.

RESULTS

During the 2 years, treatment with other second-line drugs was needed for 12 patients in the prednisone group (43%) and 8 in the chloroquine group (29%). Functional capacity and disease activity improved significantly in both groups and did not differ significantly between the groups, except for a greater improvement in the prednisone group at 1 month. Radiographic scores for joint destruction progressed similarly in both groups. There was a nonsignificant excess bone loss of 1.8% in the spine and 1.5% in the hip in the prednisone group, compared with the chloroquine group.

CONCLUSION

Neither treatment was entirely satisfactory since a significant number of patients needed an additional second-line drug over the 2-year period.

Chloroquine treatment of interstitial lung disease in children

Seven children aged 3 months to 11 years with histologically confirmed interstitial lung disease (ILD) [6 with desquamative interstitial pneumonitis (DIP) and 1 with chronic interstitial pneumonitis] were treated with chloroquine, 10 mg/kg/day. One patient, diagnosed late in the course of the disease, died after three weeks of treatment, despite the addition of systemic corticosteroids. Another patient responded to combined therapy with chloroquine and prednisone and had a normal lung biopsy after 6 months of treatment. He underwent surgical repair of mitral valve stenosis and died after extensive brain infarction. The other 5 patients responded well to chloroquine therapy with major improvement in oxygenation within a few weeks and in lung function over the next few months. They remained well clinically and physiologically, including a normal response to incremental exercise, during a mean follow-up period of 9.8 years (range 3.5 to 15.7 years). None of the patients has developed retinopathy or any other ocular complication. Bronchoalveolar lavage was a useful tool for evaluation of the activity of the disease (predominance of neutrophils) in 3 out of 4 patients. We suggest that chloroquine should be considered as an effective treatment in ILD in children. Incremental exercise test may be helpful for routine follow-up and evaluation of the efficacy of a specific treatment.

A randomized, double-blind, 24-week controlled study of low-dose cyclosporine versus chloroquine for early rheumatoid arthritis

OBJECTIVE

To investigate whether low-dose cyclosporin A (CSA) is safe and effective in comparison with chloroquine (CQ) in patients with early rheumatoid arthritis (RA).

METHODS

We performed a randomized, double-blind study comparing CSA with CQ in patients with early RA (duration < 2 years) who had had active disease for at least 3 months. Forty-four RA patients with a mean disease duration of 6 months were randomly allocated to receive CSA (initial dosage 2.5 mg/kg/day, maintenance dosage 3.6 mg/kg/day) or CQ (initial dosage 300 mg/day, maintenance dosage 100 mg/day) for 24 weeks.

RESULTS

Five patients (2 taking CSA and 3 taking CQ) discontinued the study prematurely. Intention-to-treat analysis disclosed a decrease in the swollen joint count by 7 in both groups. The erythrocyte sedimentation rate and C-reactive protein level did not change significantly. CSA and CQ were tolerated equally well, although mild paraesthesia occurred more frequently in the CSA-treated group. The serum creatinine level increased by 13 mumoles/liter (95% confidence interval [95% CI] 4, 22) in the CSA group and by 6 mumoles/liter (95% CI 1, 11) in the CQ group (difference not statistically significant).

CONCLUSION

Both CSA and CQ are effective in alleviating the symptoms of active early RA. There is only slightly impaired renal function after 24 weeks of drug administration of either drug in patients with early RA.

The ocular safety of hydroxychloroquine

The insert currently supplied with hydroxychloroquine states that patients should have an initial ophthalmological assessment and then regular assessments every 3 months. The rheumatologist should expect a report from the ophthalmologist, which includes a corneal assessment of tissue dose, a reference to visual field defects if present on the Amsler grid, and a comment concerning the status of the patient's color vision. Daily dose is more important than duration of dose, regarding maculopathy. The visual prognosis of retinopathy is excellent if the diagnosis is made at an early stage of the disease. This report suggests that ophthalmological review need only occur initially and on a yearly basis if the daily dose of hydroxychloroquine is less than 6.5 mg/kg/d and the duration of therapy is less than 9 years.

Comparative efficacy and safety of advanced drug therapy in children with juvenile rheumatoid arthritis

Results from three randomized placebo-controlled trials were combined in a meta-analysis to compare the clinical utility of four advanced drug therapy agents used to treat juvenile rheumatoid arthritis (JRA): D-penicillamine (10 mg/kg/d), hydroxychloroquine (6 mg/kg/d), auranofin (oral gold, 0.15 to 0.20 mg/kg/d), and two low dose levels of methotrexate [5MTX, 5 mg/M2/wk; 10MTX, 10 mg/M2/wk]. A total of 520 children with JRA were enrolled into these trials. Only 10MTX resulted in significantly greater improvement than placebo in variables that assess effectiveness: physician's global assessment, a composite index, and erythrocyte sedimentation rate. Treatment effect sizes were the largest in the 10MTX group for all articular disease indices. The short-term safety profiles were similar across all treatment groups. It is concluded that the current trend among pediatric rheumatologists to use oral methotrexate as the first advanced drug therapy in JRA is appropriate and that the minimum effective dose is 10 mg/M2/wk.

Antimalarials for children: indications, toxicities, and guidelines

The use of antimalarial drugs in children has been discussed extensively in the rheumatology literature, but there is scant information in the dermatology literature. We discuss indications, dosing, administration, and side effects of antimalarial drugs in children as well as skin diseases in children who have been treated with chloroquine or hydroxychloroquine.

Continuation of long term treatment with hydroxychloroquine in systemic lupus erythematosus and rheumatoid arthritis

BACKGROUND

Hydroxychloroquine is used for the treatment of rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE). Long term studies have shown a high rate of termination of hydroxychloroquine treatment in patients with RA. Although it has been shown that discontinuation of treatment with hydroxychloroquine is associated with exacerbation of SLE, long term maintenance rates of treatment with hydroxychloroquine in patients with SLE have not been investigated.

METHODS

Hydroxychloroquine use in patients with RA and SLE in a group of patients in a single community rheumatology practice was studied. Information was drawn from a computer drug use database containing details of the beginning and end of treatment. Data were analysed using life table methods.

RESULTS

Four hundred and three treatment episodes (366 patients with RA, 37 patients with SLE) were observed over eight years. In patients with RA, the cumulative probability of discontinuing treatment was 37% at 12 months and 54% at 24 months. In contrast, hydroxychloroquine treatment of patients with SLE continued over significantly longer periods of time (p < 0.001); the discontinuation probabilities at 12 and 24 months were 8 and 24% respectively. Treatment terminations were predominantly for inefficacy; terminations for toxicity were limited to the first 19 months of treatment. No ocular toxicity was observed.

CONCLUSIONS

Treatment of patients with RA in a community rheumatology practice with hydroxychloroquine has a low probability of long term continuation, mostly because of inadequate control of disease manifestations rather than toxicity. In patients with SLE, treatment with hydroxychloroquine has a significantly higher probability of long term continuation.

Chloroquine levels in blood during chronic treatment of patients with rheumatoid arthritis

Blood levels of racemic chloroquine and its main metabolites desethylchloroquine and bisdesethylchloroquine were measured in 29 patients treated chronically for rheumatoid arthritis. In six patients, the concentrations were followed during a one day dosage interval. There was considerable intersubject variability in the steady state blood concentrations of chloroquine (range 36.6 to 3895 ng.ml-1) and its two main biotransformation products; the latter represented, respectively, 47.7% and 12.9% of the concentration of chloroquine. This finding shows the need for further studies in view of the known toxic effects of chloroquine and the inevitable accumulation due to the exceptionally long residence time of the compound and its metabolites. The main requirement, which has not yet been met, for adding chloroquine to the list of drugs for which therapeutic drug monitoring is useful, is the lack of information about its mechanism of action, and consequently the dose-effect relationships of its therapeutic and toxic actions. Regular ophthalmic examination, in particular, is strongly recommended. The relatively high concentrations of desethylchloroquine and bisdesethylchloroquine found during chronic treatment show the need for more information about the therapeutic value and adverse effects of the metabolites.

Rheumatoid arthritis. New developments in treatment

If a patient with active rheumatoid arthritis does not obtain significant relief from nonsteroidal anti-inflammatory drugs, prompt institution of disease-modifying antirheumatic drugs (DMARDs) is recommended. If one agent fails, another may be tried. At present, hydroxychloroquine (Plaquenil) sulfate is one of the most widely used and best tolerated. Careful follow-up is essential with all DMARDs, however, because toxic effects may be severe and sometimes unpredictable.

A randomized study of the effect of withdrawing hydroxychloroquine sulfate in systemic lupus erythematosus

BACKGROUND

The antimalarial drug hydroxychloroquine is thought to be effective in controlling some of the manifestations of systemic lupus erythematosus, but its effectiveness has not been demonstrated conclusively.

METHODS

We conducted a six-month, randomized, double-blind, placebo-controlled study of the effect of discontinuing hydroxychloroquine sulfate treatment in 47 patients with clinically stable systemic lupus erythematosus. The patients were randomly assigned to continue their same dose of hydroxychloroquine (n = 25) or to receive placebo (n = 22) for 24 weeks. Ten patients in each group were also taking prednisone.

RESULTS

The relative risk of a clinical flare-up, defined as the development of specific clinical manifestations of systemic lupus erythematosus or an increase in their severity, was 2.5 times higher (95 percent confidence interval, 1.08 to 5.58) in the patients taking placebo than in those continuing to take hydroxychloroquine (16 of 22 patients vs. 9 of 25 had flare-ups), and the time to a flare-up was shorter (P = 0.02). The relative risk of a severe exacerbation of disease that required withdrawal from the study was 6.1 times higher (95 percent confidence interval, 0.72 to 52.44) for the patients taking placebo (5 of 22 patients vs. 1 of 25 had severe exacerbations of disease). Changes in the dose of prednisone were not different in the two groups.

CONCLUSIONS

Patients with quiescent systemic lupus erythematosus who are taking hydroxychloroquine are less likely to have a clinical flare-up if they are maintained on the drug.

Sequential pulmonary function measurements during treatment of infantile chronic interstitial pneumonitis

Three infants with histologically confirmed chronic interstitial pneumonitis were treated with monthly intravenously administered high doses of methylprednisolone with or without daily hydroxychloroquine therapy. We applied the multiple occlusion technique to measure the static respiratory system compliance, and the end-inspiratory occlusion technique to measure passive respiratory system compliance, resistance, and time constant. When assessed by clinical criteria and pulmonary function measurements, all three patients showed improvement with this treatment. Clinical improvement was associated with an increase in respiratory system compliance as measured by both techniques (60% to 100% increase in all patients). The passive respiratory resistance and the time constant did not closely reflect the clinical course. We conclude (1) that high doses (pulses) of methylprednisolone and daily oral doses of hydroxychloroquine are effective in the treatment of infantile chronic interstitial pneumonitis and (2) that the respiratory system compliance, measured by both pulmonary function techniques, correlates well with the response to treatment and change in clinical status.

Treatment of rheumatoid arthritis

The management of the rheumatoid patient involves the considered use of pharmacologic agents as therapies to induce symptomatic relief and to reduce disease activity. Aspirin and nonsteroidal antiinflammatory drugs are used initially to lessen the degree of pain and swelling associated with the inflammatory disease process. The aggressive institution of second-line therapy, previously known as disease-modifying antiinflammatory rheumatic drugs, is advocated to modify the disease course itself. These second-line treatments include antimalarials, gold salts, methotrexate, d-penicillamine, and azathioprine. Randomized placebo controlled trials have demonstrated the efficacy of these compounds in this illness. Improvement in standard parameters of disease activity (number of painful and swollen joints, duration of morning stiffness, erythrocyte sedimentation rate) can be related to the therapeutic value of second-line agents. Whether they modify radiographic progression is under rigorous study. Newer therapies under research investigation include sulfasalazine, cyclosporin A, and combination therapy.

A double blind comparative study of sulphasalazine and hydroxychloroquine in rheumatoid arthritis: evidence of an earlier effect of sulphasalazine

In a double blind, single observer, 48 week study the effects of sulphasalazine (2 g daily) and hydroxychloroquine (400 mg daily months 0-6, thereafter 200 mg daily) were compared in 60 patients with definite or classical rheumatoid arthritis. They had not been treated previously with second line drugs. The onset of response with sulphasalazine was earlier than with hydroxychloroquine. After 48 weeks a comparison of the treatments showed no statistically significant differences in disease activity variables. Adverse reaction was the main reason for withdrawal in the sulphasalazine group and lack of efficacy in the hydroxychloroquine group. All adverse reactions, one being agranulocytosis after eight weeks of sulphasalazine treatment, appeared in the first three months of treatment and were completely reversible.

Advanced drug therapy for juvenile rheumatoid arthritis

Childhood rheumatic diseases are frequently chronic, painful, and potentially debilitating. They may adversely affect growth and development, compromise future quality of life, and contribute added stress to the patient and family. Awareness of these consequences provides a stimulus to develop more effective therapeutic regimens. There is optimism that new therapeutic strategies will result in the more widespread and earlier use of drugs, including those discussed, that may substantially impede or arrest the underlying disease.

Ocular effects and safety of antimalarial agents

The clinical experiences with 1,500 patients receiving chloroquine or hydroxychloroquine over a 15-year period are reviewed. Forty-six patients with confirmed irreversible, bilateral, early chloroquine retinopathy have been followed prospectively since 1980. Patients presenting with normal color vision and relative paracentral scotomas appear not to progress over short-term follow-up of five years. Retinopathy in patients presenting with less than 20/20 vision, abnormal color vision, and positive fluorescein angiography may progress even if treatment with the medication is discontinued. The Amsler grid is an effective method of screening patients taking antimalarial agents for early relative paracentral scotomas. Color vision testing and fluorescein angiography are useful in elderly patients with age-related macular disease when visual field testing is unreliable.