An appraisal of chloroquine

A bibliometric review of drug repurposing

We have conducted a bibliometric review of drug repurposing by scanning >25 million papers in PubMed and using text-mining methods to gather, count and analyze chemical-disease therapeutic relationships. We find that >60% of the ∼35,000 drugs or drug candidates identified in our study have been tried in more than one disease, including 189 drugs that have been tried in >300 diseases each. Whereas in the majority of cases these drugs were applied in therapeutic areas close to their original use, there have been striking, and perhaps instructive, successful attempts of drug repurposing for unexpected, novel therapeutic areas.

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.

Novel paradigms for drug discovery: computational multitarget screening

An established paradigm in current drug development is (i) to identify a single protein target whose inhibition is likely to result in the successful treatment of a disease of interest; (ii) to assay experimentally large libraries of small-molecule compounds in vitro and in vivo to identify promising inhibitors in model systems; and (iii) to determine whether the findings are extensible to humans. This complex process, which is largely based on trial and error, is risk-, time- and cost-intensive. Computational (virtual) screening of drug-like compounds simultaneously against the atomic structures of multiple protein targets, taking into account protein-inhibitor dynamics, might help to identify lead inhibitors more efficiently, particularly for complex drug-resistant diseases. Here we discuss the potential benefits of this approach, using HIV-1 and Plasmodium falciparum infections as examples. We propose a virtual drug discovery 'pipeline' that will not only identify lead inhibitors efficiently, but also help minimize side-effects and toxicity, thereby increasing the likelihood of successful therapies.

Discoid lupus erythematosus and lupus profundus in childhood: a report of two cases

Discoid lupus erythematosus (DLE) is a rare disorder in childhood, with 22 cases reported in the English-language literature. Less than 2% of patients with DLE have an onset before 10 years of age. We describe two children with DLE and lupus profundus with an onset of the disease at the ages of 11 and 15 years and focus on likely histopathologic differences between DLE in children and in adults. Histopathologic characteristics for childhood DLE might be an intense periadnexal and perivascular infiltrate extending into the interstitium and subcutaneous tissue consisting of lymphocytes, histiocytes, eosinophilic granulocytes, and plasma cells and lacking epidermal atrophy. The diagnosis of DLE in our two patients was established by clinicopathologic correlation based on clinical presentation, histologic and immunofluorescent findings in skin biopsy specimens, and the absence of clinical and laboratory evidence of systemic involvement. Therapy with antimalarials resulted in reduction of the skin lesions, but in one patient severe lipoatrophy occurred.

The use of antimalarials in combination with other disease modifying agents in RA – the British experience

Antimalarial drugs are effective disease modifying agents in RA with a low incidence of serious toxic effects. Recently, combinations of second-line agents have been used in RA in attempts to treat patients with no response to a number of single agents, or suboptimal response to a single agent.

Combinations of drugs have been selected for maximum efficacy and minimum toxicity, but clinical trials are difficult to design and interpret. In particular, ensuring adequate power to detect small differences in response poses a major problem. Antimalarials are an attractive choice for combination therapy due to their efficacy, mechanisms of action and toxicity profile.

In this review, the evidence for the use of antimalarials in combination in RA is examined. No advantage has been shown in combining antimalarials with gold, penicillamine or sulphasalazine compared with monotherapeutic regimens. There is some evidence to suggest a beneficial combination of antimalarials with methotrexate, but this is as yet inconclusive. Open non-randomised uncontrolled studies have shown that antimalarials combined with cytotoxic agents are effective but highly toxic.

The authors conclude that there is little good evidence to support the introduction of combination second-line drug therapy for RA into widespread therapeutic use.

Improved pulmonary function in systemic sclerosis after treatment with cyclophosphamide

OBJECTIVE

Pulmonary fibrosis is a common feature of systemic sclerosis (SSc) and a major cause of morbidity and mortality. Since alveolitis may be an essential step in the development of pulmonary fibrosis, we investigated the use of immunosuppressive drug therapy to improve pulmonary function in patients with SSc.

METHODS

Eighteen patients with progressive pulmonary dysfunction, diminished vital capacity (VC), and/or decreased static lung compliance (Cst) were treated with cyclophosphamide and corticosteroids for 1 year. Eight patients had diffuse cutaneous SSc and 10 had limited cutaneous SSc. The median disease duration was 2.5 years (range 0.5-17 years).

RESULTS

VC increased in 14 of 18 patients and the median VC rose from 74% to 80% of predicted. Cst improved in 8 of 12 patients and the median Cst increased from 59% to 66% of predicted. Pulmonary nonfibrotic opacities disappeared in 9 of 12 patients. The erythrocyte sedimentation rate (ESR) and serum concentrations of orosomucoid, C-reactive protein, and aminopropeptide type III collagen all improved. The patients were divided into 2 groups based on the presence or absence of elevations in acute-phase protein levels and ESR before therapy. Among the 12 patients with biochemical signs of inflammation, VC increased in 11, and Cst improved or was unchanged in 7 of the 8 who were tested. The median VC in this subgroup increased from 73% to 80% of predicted and the median Cst increased from 57% to 60% of predicted. In the group of 18 patients overall, the skin score decreased, while esophageal and renal function remained stable.

CONCLUSION

Cyclophosphamide may have a beneficial effect on pulmonary fibrosis in patients with SSc and elevated levels of acute-phase proteins. Controlled trials of cyclophosphamide in pulmonary SSc should be performed and should focus on such patients.

Neurotoxic effects of chloroquine in vitro

In order to investigate chloroquine retinopathy, the effect of chloroquine on the viability and differentiation of primary cell cultures of embryonic chick neuronal retina, retinal pigment epithelium (RPE), brain and meninges were investigated. The sensitivity of the cells, measured as reduction of viability, showed the following order: RPE greater than brain greater than meninges greater than neuronal retina. The human serum chloroquine concentration range which leads to ocular damage in vivo was identical to the concentration range in the culture medium which affected RPE viability. In addition, the differentiation of nerve cells in brain cell cultures was affected at much lower chloroquine concentrations than astroglia cells or nerve cells in neuronal retina cell cultures. Some possible mechanisms for chloroquine retinopathy were assessed.

Effects of immunomodulating therapy in systemic sclerosis

We reviewed studies concerning immunomodulating therapy in systemic sclerosis. These comprise mostly uncontrolled trials and case reports. Some of these studies hint at a possible beneficial effect of antimetabolites (azathioprine, 5-fluoro-uracil and methotrexate), cyclosporine and interferon-gamma. However, to give a clearcut answer on the efficacy of these drugs in systemic sclerosis, controlled studies are urgently needed.

The effect of chloroquine and hyperthermia on murine neuroblastoma

A number of reports suggest that hyperthermia is an effective adjunctive treatment modality in management of neural crest tumors. Recent studies have demonstrated a synergistic effect of induced hyperthermia when coupled with chloroquine in an in vitro model. This study examines the effect of chloroquine and hyperthermia in an in vivo murine neuroblastoma model. Forty-seven Ajax white mice (weighing 20 to 30 g) received a subaxillary tumor burden (C-1300 murine neuroblastoma) per trochar (1.25 x 10(6) cells). The tumor was then incubated for 9 days. Mice were then divided into four groups: group 1, controls (n = 15); group 2, hyperthermia (n = 12); group 3, chloroquine (n = 10); and group 4, chloroquine with hyperthermia (n = 10). Hyperthermia was induced with 40 to 69 mW/cm2 at 2,450 MHz microwave radiation for 4 minutes to achieve a temperature of 41.5 degrees C for 10 of 14 treatment days. Chloroquine was administered intraperitoneally at a dose of 40 mg/kg body weight for 10 of 14 treatment days. Mice were weighed and tumor size was determined daily. Animals were killed on day 21 and postmortem examination was performed, with tumors graded histologically. Animal weight, tumor weight, and tumor size were similar for all groups (P greater than .05). Mortality was 6% in group 1, 25% in group 2, 50% in group 3, and 40% in group 4 (P less than .05). Rate of tumor metastases was also statistically different from controls: group 1, 0%; group 2, 60%; group 3, 90%; and group 4, 90% (P less than .05).(ABSTRACT TRUNCATED AT 250 WORDS)

Photoaging/photodamage and photoprotection

Exposure to sunlight can produce both acute and long-term effects. Acute changes include erythema, photosensitivity, and immunologic alterations. Long-term consequences include carcinogenesis and photoaging. All effects can be minimized by photoprotection. This article reviews the adverse effects of sun exposure and strategies to reduce photodamage.

Immunosuppression with chlorambucil, versus placebo, for scleroderma. Results of a three-year, parallel, randomized, double-blind study

Placebo and chlorambucil (0.05-0.1 mg/kg/day) were compared as treatments for scleroderma in a 3-year, randomized, double-blind, parallel study of 65 patients. Slopes of change over time, calculated for each organ system of each patient, failed to show significant differences between treatment groups. An immunosuppressive effect in the chlorambucil-treated group was shown by decreases in the white blood cell counts (P = 0.02), platelet counts (P = 0.04), lymphocyte counts (P = 0.001), IgA/IgM concentrations (P less than or equal to 0.05), and wheal size on mumps skin tests (P = 0.02). Three years of immunosuppressive treatment with chlorambucil did not benefit this scleroderma population.

Visceral improvement following combined plasmapheresis and immunosuppressive drug therapy in progressive systemic sclerosis

In a two-year prospective therapeutic trial, 15 patients with progressive systemic sclerosis (PSS) were treated with immunosuppressive drug therapy with or without long-term plasmapheresis. Before the trial all patients had severe involvement of either the esophagus, lungs or kidneys. One patient died of renal failure and another 2 patients withdrew unimproved. In the remaining 12 patients, objective improvement occurred in all but one. The degree and extent of skin involvement decreased significantly (p less than 0.01). Cineradiography revealed increased esophageal motility in 4 patients. Pulmonary function measured as total lung capacity and static lung compliance improved (p less than 0.01). In 4 patients the number of premature atrial or ventricular contractions at 24 h ECG monitoring decreased, as did the concentrations of immunoglobulins and ANA titres in serum. Although it could not be ascertained whether the clinical improvement was associated with combined therapy or immunosuppressive drug treatment alone, our results suggest that immunosuppressive therapy is beneficial in advanced PSS.

Lupus profundus in children: treatment with hydroxychloroquine

Discoid lupus erythematosus and lupus profundus, rare in children, are described in two young girls, one with onset at 3 1/2 years of age, the other at 8 years of age. Unusual nodules of the face that ultimately healed with atrophy and hyperpigmentation showed histologic and immunofluorescent confirmation of lupus erythematosus. These patients, the second and third in the English literature to be treated for childhood lupus profundus with antimalarials, responded successfully to hydroxychloroquine. No systemic involvement was found.

Toxic psychosis: a complication of antimalarial therapy

A case is reported of toxic psychosis in a patient with a diagnosis of discoid lupus erythematosus treated with hydroxychloroquine. The dose slightly exceeded the maximum recommended dose for 10 days because of a pharmacy error. Since more antimalarials are being used for various diseases, attention is called to this possible complication with a subtle onset.

Chloroquine: its effect on leucocyte auto- and heterophagocytosis

The effect of chloroquine on phagocytosis and leucocyte ultrastructure has been examined. Incubation of neutrophils in 50 micrograms/ml chloroquine for 15 minutes produced a significant inhibition of latex particle uptake. After 90 minutes both 50 and 5 micrograms/ml inhibited phagocytosis while 7 of 9 cases were also inhibited at 0.5 micrograms/ml. However, after 4 hours 50 micrograms/ml chloroquine caused neutrophil granule vacuolation and a massive increase in autophagosomes in other cell types. Incubation in 5 to 0.05 micrograms/ml, which includes therapeutic plasma levels, had no effect on neutrophil ultrastructure but produced a dose-related increase in the number of lymphocytes containing autophagosomes, reflecting altered lysosomal function. As the antimalarial effect of chloroquine is manifested by giant autophagosome formation in Plasmodium, a common antirheumatic and antimalarial mechanism of action is postulated.

Antimalarial drugs for rheumatoid arthritis

Chloroquine and hydroxychloroquine effectively suppress rheumatoid arthritis with a superior benefit to risk ratio. Controlled studies demonstrate moderate efficacy in about 70 percent of patients. High-grade suppression is seen in 15 percent and partial suppression in 55 percent. The dropout rate for poor efficacy is 30 percent and for side effects 3 to 7 percent. Most studies show antimalarials to be almost equivalent to chrysotherapy in potency. Antimalarials are indicated for active rheumatoid arthritis not optimally controlled with nonsteroidal anti-inflammatory drugs and for all cases of progressive disease. Therapy is continued indefinitely. Safe use of these drugs depends on daily dosage. With the single exception of late stage retinopathy, other adverse effects are fully reversible. Strict adherence to three tested safety rules virtually eliminates retinopathy and prevents loss of vision: (1) limit the daily dosage: chloroquine 3.5 to 4.0 mg/kg per day or hydroxychloroquine 6.0 to 6.5 mg/kg per day based on lean body weight; (2) subject the patient to an annual ocular examination to age 65, twice annually thereafter; (3) adjust treatment for pharmacokinetic variables. The lower risk and nearly comparable efficacy make antimalarials first choice among remittive drugs.

Hydroxychloroquine in the treatment of rheumatoid arthritis

One hundred eight patients with rheumatoid arthritis received hydroxychloroquine for six to 24 months and were studied retrospectively to examine long-term efficacy and predictors of a favorable response to the drug. Response was classified in terms of reduction of active joint count and morning stiffness. Thirteen patients (12 percent) showed a complete remission. Fifteen patients (14 percent) had a 75 percent or greater response. Forty patients (37 percent) had a 30 to 75 percent response. Thirty-two (30 percent) had no response. Toxicity occurred in eight patients (7 percent) before clinical efficacy could be assessed. Seven of the 68 with response had a flare of disease after initial improvement. Of multiple clinical and laboratory parameters tested, only a stronger baseline grip strength was found to be statistically significant (p less than 0.001) in predicting a favorable response. Thus, hydroxychloroquine is an effective drug in the management of rheumatoid arthritis.

Pharmacologic actions of 4-aminoquinoline compounds

The pharmacokinetics, physiologic effects, and the metabolization of chloroquine and hydroxychloroquine are all similar. Their concentrations in plasma and tissue are directly related to daily dosing. The highest concentrations are found in melanin-containing tissues, particularly the choroid and ciliary body of the eye. The pharmacologic effects of 4-aminoquinoline compounds are reviewed in detail. It is likely that the rheumatologic effectiveness of these agents is primarily related to lysosomal actions. The drug-induced lysosomal abnormalities include diminished vesicle fusion, diminished exocytosis, and reversible "lysosomal storage disease." It is likely that the retinal toxicity of these drugs is one manifestation of the altered lysosomal physiology involving the retinal pigmented epithelium. Tissue of retinal pigmented epithelium is similar to that of the bone-marrow-derived macrophage. Depression of extra-oculogram is an early sign of excessive dosage and can be used to measure potential toxicity during therapy with 4-aminoquinolines. Dosages ranging from 3.5 to 4.0 mg/kg per day for chloroquine and 6.0 to 6.5 mg/kg per day for hydroxychloroquine are clinically safe.

Dose refinements in long-term therapy of rheumatoid arthritis with antimalarials

No eye disease was detected in over 900 rheumatoid arthritis patients treated with less than 4.0 mg/kg per day of chloroquine or less than 6.5 mg/kg per day of hydroxychloroquine for a mean of about seven years. I therefore consider these dosage rates safe, since they are below the threshold of retinal toxicity. This is based on more than 6,000 patient-years of drug exposure. That dosage threshold for retinopathy appears to be 5.1 mg/kg per day for chloroquine and 7.8 mg/kg per day for hydroxychloroquine according to my studies with these compounds. The daily dosage rate, rather than total drug accumulation, seems to determine the development of eye disease. To prevent overdosage, dosing should be calculated not on the actual weight of the patient but on ideal (lean) body weight. Furthermore, the patient's renal and liver function should also be taken into account to avoid overdosage. Since exposure to light amplifies the risk of retinopathy in patients treated with antimalarials, dark sunglasses are recommended for patients spending much time in sunlight.

Animal toxicity and pharmacokinetics of hydroxychloroquine sulfate

Chloroquine is two to three times as toxic in animals as hydroxychloroquine, even though various single and repeated oral dosage regimens in man have given nearly identical plasma level curves. Tissue distributions are qualitatively similar for both drugs in albino rats--namely, bone, fat, and brain less than muscle less than eye less than heart less than kidney less than liver less than lung less than spleen less than adrenal--but the absolute distribution values are about 2.5 times higher for chloroquine. The metabolism of chloroquine and hydroxychloroquine differs only in that the latter drug gives two first-stage metabolites, whereas chloroquine gives one. Oral absorption of both drugs in man is nearly complete. However, three times as much chloroquine as hydroxychloroquine appears in the urine, and three times as much hydroxychloroquine as chloroquine appears in the feces.

Gas chromatographic analysis of chloroquine after a unique reaction with chloroformates

A specific method for the gas chromatographic determination of chloroquine (CQ) after derivatization with chloroformates, using 9-bromophenanthrene as the internal standard and a column filled with 3% OV-17 on 80-100 mesh Supelcoport is described. Derivatization with chloroformates produced a pyrrolidine derivative, 4-(2-methyl-1-pyrrolidyl)-7-chloroquinoline with CQ, and a carbamate with desethylchloroquine. The chloroformate reaction for CQ is thus selective in the presence of CQ metabolites. The method based on flame ionization detection is highly suitable for quantitation of CQ in urine.

Sunscreens: topical and systemic approaches for protection of human skin against harmful effects of solar radiation

This review deals with topical and systemic approaches for protection of human skin against the harmful effects of solar radiation. Two concerns about the deleterious effects of sun exposure involve: (1) acute effects (e.g., sunburn and drug-induced phototoxicity) and (2) potential long-term risks of repeated sun exposures leading to development of solar elastosis, keratoses, induction of both nonmelanoma and melanoma skin cancer, and alteration of immune responses and functions. Action spectra of normal and abnormal reactions of human skin to acute and chronic effects of solar radiation are presented with a view to helping the physician prescribe the appropriate sunscreens. Factors that influence acute effects of sunburn are reviewed. Various artificial methods effective in minimizing or preventing harmful effects of solar radiation, both in normal individuals and in patients with photosensitivity-related problems, are discussed. Emphasis is placed on the commercially available chemical sunscreens and their properties. Sun protection factor (SPF) values of several brand-name formulations determined with a solar simulator under indoor conditions (laboratory) and with solar radiation under natural, field conditions are presented. Factors responsible for variations of SPF values observed under indoor and outdoor conditions are reviewed. Systemic photoprotective agents and their limitations are outlined. The photobiology of melanin pigmentation (the tanning reaction) is briefly discussed, with emphasis on the dangers of using quick-tanning lotions for stimulation of the tanning reaction.

Antimalarials and ophthalmologic safety

Antimalarial drugs were shown to be useful agents in the treatment of discoid and systemic lupus erythematosus in 1951. However, by 1966, fear of retinal toxicity and the availability of alternative therapies had led to limited use of antimalarials. Continued experience with these alternative therapies has made their intrinsic, sometimes devastating toxicities more evident and has contributed to the renewed interest in antimalarial agents evident in the number of comprehensive reviews appearing recently in the dermatology literature. Many of these reviews, while generally excellent, have propagated some apparent misconceptions by disregarding or de-emphasizing data suggesting that irreversible retinal toxicity due to antimalarials can be easily avoided by judicious daily dosage and regular ophthalmologic follow-up. This article will discuss the historical basis of these misconceptions and the subsequent studies which suggest that antimalarial retinal toxicity can be avoided without sacrificing the therapeutic efficacy of these agents.

Biochemical indices of response to hydroxychloroquine and sodium aurothiomalate in rheumatoid arthritis

Biochemical and clinical changes have been monitored in 30 patients with rheumatoid arthritis treated with either hydroxychloroquine or sodium aurothiomalate over a period of 6 months. Acute-phase reactants improved in both treatment groups, while serum sulphydryl and serum histidine improved only in the gold-treated patients. Correlation matrices were constructed from mean clinical and biochemical data at successive clinic visits. Correlations obtained with gold were more frequent and of a higher level of significance than those obtained with hydroxychloroquine at the doses we studied. This lends support to the use of correlation matrices as a screening test for potential long-term antirheumatoid activity of drugs in man.

Plasmapheresis and immunosuppressive drug therapy in scleroderma

In an uncontrolled clinical trial, plasmapheresis combined with prednisone and cyclophosphamide therapy produced clinical improvement in 14 of 15 scleroderma patients with varying degrees of skin and internal organ involvement. All improved patients showed a gradual loosening of hide-bound skin, relaxation of contractures, and healing cutaneous ulcers, when present. Severe gastrointestinal symptoms were ameliorated in 4 patients, severe polymyositis was largely reversed in 2 patients, and pulmonary and cardiac function was improved in others. After initial improvement, however, 2 patients died during the period of study and another withdrew unimproved. Antinuclear antibody (ANA) titers declined relatively more than total IgG levels with plasmapheresis in 6 of the 9 patients who had elevated titers. Increased levels of endothelial cell cytotoxic activity found in 11 of the 15 patients were significantly reduced by plasmapheresis. Elevated levels of circulating immune complexes were found in only 4 of the 15 patients. Skin biopsies from adjacent sites taken before and after plasmapheresis in 10 patients all showed less swollen dermal collagen with increased ground substance between collagen bundles in the second biopsy. Although the effects of plasmapheresis cannot be dissociated from those of the immunosuppressive drug therapy, our results suggest that plasmapheresis combined with immunosuppressive drug therapy may find a place in the management of patients with moderate to severe scleroderma. This study implicates circulating factors in the pathogenesis of the disease.

Antimalarials

The antimalarials, chloroquine, hydroxychloroquine, and quinacrine, are used primarily for malaria; but they can be beneficial for cutaneous lupus erythematosus (LE), polymorphous light eruption, solar urticaria, and porphyria cutanea tarda. Antimalarials bind to deoxyribonucleic acid (DNA) which prevents DNA and ribonucleic acid (RNA) polymerase reactions and DNA heat inactivation; and they inhibit the LE cell phenomenon, antinuclear antibody reactions, and suppress lymphocyte transformation. By competing with calcium ion, they stabilize membranes and have an anesthetic effect. Their anti-inflammatory potential is due to their inhibition of hydrolytic enzymes, stabilization of lysosomes, interference with prostaglandin synthesis, blocking of chemotaxis, and antagonism of histamine responses. The antimalarials have no sunscreening properties. The most common toxic effects are cutaneous pigmentation, nausea, vomiting, diarrhea, mild ileus, and cycloplegia. There has been a reluctance to use chloroquine and hydroxychloroquine because of the possibility of retinopathy. However, if the "safe" daily dose limit of chloroquine, 2 mg per pound of body weight, and of hydroxychloroquine, 3.5 mg per pound of body weight, is followed, the chance of retinopathy is slight. Quinacrine does not cause retinopathy, but it has more cutaneous side effects than the other two agents.

Antimalarial therapy for lupus erythematosus: an apparent advantage of quinacrine

A retrospective study of 26 quinacrine-treated lupus erythematosus patients failed to show evidence of drug-induced ocular changes. Although quinacrine commonly produces minor side effects, such as yellow discoloration of the skin, and may rarely produce very serious side effects, such as aplastic anemia, it appears to produce much less oculotoxicity than does chloroquine.

Sensitive method for the determination of chloroquine and its metabolite desethyl-chloroquine in human plasma and urine by high-performance liquid chromatography

A method has been developed for the rapid quantitative analysis of chloroquine and its metabolite desethyl-chloroquine in plasma, blood and urine using high-performance liquid chromatography. An ethylene dichloride extract of the alkalinized biological samples was extracted with dilute acid and chromatographed on a reversed-phase column. Phosphate buffer in acetonitrile was used as the mobile phase with perchlorate as the counter-ion. Ultraviolet absorption at 254 or 340 nm or fluorescence detection was used. The fluorescence spectra and the fluorescence quantum yield of the substances were determined. Chloroquine and desethyl-chloroquine concentrations in the range of 10 nmol/l (UV-detection) and of 0.5 nmol/l (fluorescence detection) could be accurately measured with a relative standard deviation of 12%. The method should be adequate for therapeutic and pharmacokinetic studies.

The uptake of 14C-chloroquine by mouse pancreatic islets in vitro

The uptake of 14C-chloroquine by isolated mouse pancreatic islets in vitro was investigated. The islets were found to have a very high capacity to accumulate the substance. The uptake of 14C-chloroquine in the islets was a saturable process. Metabolic inhibitors, ouabain, anaerobic conditions and absence of glucose did not inhibit the uptake of 14C-chloroquine in the islets, suggesting that the substance is accumulated by some means other than energy-dependent active transport or pinocytosis. The uptake of 14C-chloroquine was inhibited by low temperature and low pH and in the presence of mepacrine, chlorpromazine, imipramine and desmethylimipramine. Only a small part of the 14C-chloroquine which had been taken up in the islets left the cells during 45 min. incubation in non-radioactive media. Two possible mechanisms for the uptake of 14C-chloroquine in the islets are considered: (1) The accumulation may be due to a binding of the substance to cellular constituents. (2) Chloroquine may be trapped by protonation within lysosomes or other membrane-surrounded organelles with low pH.

Long-term course of chloroquine retinopathy after cessation of medication

Seven patients with chloroquine retinopathy were examined ten years after their therapy with chloroquine or hydroxychloroquine, or both, had been discontinued and an additional five patients with chloroquine retinopathy were similarly examined from two to eight years after their therapy had been discontinued. Visual acuity, visual fields, and ophthalmoscopic examinations were compared to those performed at the time therapy was discontinued. These long-term observations confirmed the previously published observations based on short-term studies that chloroquine retinopathy tends to remain stable after therapy is discontinued, although a few patients in the early stages of retinopathy may show regression and occasionally a patient with a more advanced stage of the disease may show progression.

Chloroquine retinopathy in patients with rheumatoid arthritis

270 consecutive patients with rheumatoid arthritis who had received chloroquine therapy were examined ophthalmologically for toxic retinal lesions. The total annual dose of chloroquine was 70-75 g. The maximum total dose given was 1330 g. The duration of treatment ranged up to 15 years. The primary material was divided into four groups according to total chloroquine dose received: greater than 100 g, 101-300 g, 301-600 g, and less than 600 g. Each dose group was arbitrarily split into two age groups, one with patients under 63 years of age and the other with patients over 63, in order to analyse the effect of age upon the ocular findings. In the present study, slight macular changes were included in the concept of maculopathy and were not thought to contra-indicate chloroquine therapy. Macular changes were found in about 25% of the patients, regardless of age in the lowest dosage group. The frequency of maculopathy increased with increasing total dose only in the older age group. It was also shown that the frequency of maculopathies and other eye diseases also increased with increasing age. This was evident even from the age of 50. The only patient with chloroquine retinopathy was an inadequately controlled 74-year-old woman. Chloroquine treatment of rheumatoid arthritis in the absence of any other disease which may cause retinopathy implies negligible risks in adult patients under 50 years of age. These patients could be less frequently checked. Older patients require regular ophthalmological checks. It is important to use the smallest effective dose possible, and never higher than 4 mg of chloroquine phosphate/kg body weight and day for 10 months annually; in elderly patients, preferably even lower doses.

[Postnatal development of the rat retina under DNS-inhibitor (chloroquinediphosphate) mediation (author's transl)]

The morphogenesis of retina has been studied in 1-15 day-old rats after a single injection of chloroquinediphosphate. Beside degeneration of neuroblasts, rate of development was markedly retarded as evidence by regression of the strata reticulares. Neuroblasts or receptor cells remained disorganized and were arranged in rosettes. In the inner layer containing the third neuron myelinated bodies were produced by the drug.

Distribution of an 125I-labelled chloroquine analogue in a pregnant macaca monkey

Whole body autoradiography of a pregnant monkey (Macaca irus) of late gestation was performed 72 h after an intravenous injection of the 125I-labelled chloroquine analogue 4-(3-dimethylaminopropylamino)-7-iodoquinoline (DAPQ). The overall distribution pattern in the monkey was similar to that which was earlier observed in rodents. A few species differences, however, were found in the monkey as compared to the rodents: a high accumulation in the inner part of the adrenal cortex, a high level in the central nervous system, and generally a higher retention in the tissues. The accumulation in the adrenal cortex may be of significance for the cortisone-like effects of the 4-aminoquinolines in rheumatoid arthritis and allied conditions. The fact that no accumulation was found in the adrenal cortex of mice and rats indicates that these species may not be appropriate in studies on the mechanisms involved in the anti-inflammatory action of the 4-aminoquinolines. As was earlier observed in small rodents the melanin containing structures accumulated the drug. In both the mother and the fetus a high concentration was thus seen in the uveal tract of the eye, in the inner ear (in the stria vascularis of the cochlea and the planum semilunatum of the ampullae) and in the hair follicles. This accumulation can be related to reported disturbances--also transplacentally induced--in vision and hearing.