Dapsone and sulfones in dermatology: overview and update

Dapsone in the management of autoimmune bullous diseases

Dapsone is used in the treatment of autoimmune bullous diseases (AIBD), a group of disorders resulting from autoimmunity directed against basement membrane and/or intercellular adhesion molecules on cutaneous and mucosal surfaces. This review summarizes the limited published data evaluating dapsone as a therapy for AIBD.

Treatment of subepidermal immunobullous diseases

The subepidermal immunobullous diseases are a group of autoimmune blistering disorders of the skin and mucous membranes that share the common features of autoantibody deposition and blister formation at the dermal-epidermal junction or basement membrane. This group includes bullous pemphigoid, linear IgA disease, dermatitis herpetiformis, and epidermolysis bullosa acquisita, among others. Although these disorders share some common features, each disease is unique in its clinical presentation, histopathology, and immunofluorescence patterns, which allows for accurate diagnosis and disease-specific treatment strategy. Treatment of these disorders is complex and requires expert knowledge of disease pathogenesis. We review common treatment approaches for each of these disorders.

Management of dermatitis herpetiformis

The major treatment strategies for DH are gluten restriction or medical treatment with sulfones. Control of the cutaneous manifestations, but not the gastrointestinal changes, is rapid with dapsone. In addition to control of the cutaneous signs and symptoms of DH, dietary gluten restriction also induces improvement of gastrointestinal morphology and is possibly protective against the development of lymphoma.

Bullous systemic lupus erythematosus

Bullous systemic lupus erythematosus (BSLE) is a rare bullous dermatosis in patients with systemic lupus erythematosus. It is characterized by clinical and histologic features, resembling either bullous pemphigoid or dermatitis herpetiformis, and a heterogeneous immunologic profile, characterized by autoimmunity to components of type VII collagen, much like epidermolysis bullosa acquisita. As understanding of the pathology of this interesting dermatologic condition has evolved, so too have criteria and profiling of BSLE. The distinct clinical, histologic, and immunologic features of BSLE represent a unique bullous disease phenotype.

Dermatitis herpetiformis. Part II. Diagnosis, management, and prognosis

The prompt recognition of the clinical features of dermatitis herpetiformis (DH) is important, but securing a definitive diagnosis requires further work-up. Recent advances in understanding of the immunologic basis for DH have led to the development and wider availability of serologic testing, which is rapidly becoming an essential part of the diagnosis and management of DH. Part II of this series will detail the diagnosis, treatment, and follow-up for patients with DH, and will particularly focus on recent advances in the field.

[Dermatitis herpetiformis: a review]

BACKGROUND

Dermatitis herpetiformis (DH) is a rare auto-immune bullous disease characterized by its almost constant association to gluten sensitivity.

OBJECTIVE

Review of literature about epidemiology, physiopathology, clinical data and treatment of DH.

METHODS

Research on Medline and Embase database without any time limit until April 2010. Because of the lack of randomized therapeutic trials in DH, retrospective series and case reports have been analyzed.

RESULTS

DH is related to auto-antibodies against epidermal transglutaminase, which belongs to the same family as tissue transglutaminase, the auto-antigen of celiac disease. Physiopathology is complex, occurring in HLA DQ2 or DQ8 predisposed patients, and implies gluten, immunological reaction in the intestinal wall then in the skin. DH and celiac disease may be encountered in the same family. DH is characterized by a very pruritic microvesicular eruption typically located on elbows, knees and buttocks. Digestive manifestations of celiac disease occur in 15% of cases. Direct immunofluorescence is necessary to confirm the diagnosis, showing granular IgA±C3 deposits in the papillary dermis. Circulating IgA and IgG antiendomysium and antitransglutaminase antibodies are detected in almost all patients at the acute phase and follow the clinical course of the disease. Gastro-intestinal endoscopy with multiple duodenal biopsies shows partial or complete villous atrophy in two thirds of cases, intraepithelial lymphocyte infiltrate in the other cases. Other auto-immune diseases may be associated in 10-20% of cases. The main long-term risk is the occurrence of T or B nodal or intestinal tract lymphoma in 2% of cases (relative risk close to 6 in several studies, but not admitted by all authors), especially if adherence to gluten-free diet is not strict. Treatment is based on dapsone, which is quickly efficient on cutaneous manifestations, but not on the digestive involvement and on strict and definitive gluten-free diet, which cures villous atrophy and reduces the risk of lymphoma.

CONCLUSION

DH is associated to a gluten enteropathy and its physiopathology is better known. Even if the risk of secondary lymphoma seems little, most of the authors recommend a definitive gluten-free diet.

Safety and tolerability of dapsone for the treatment of patients with drug-resistant, partial-onset seizures: an open-label trial

Dapsone has shown anti-convulsive properties in animal models of epilepsy. In the present study, we tested the safety and tolerability of dapsone as adjunctive therapy in adult patients with drug-resistant partial-onset seizures. Twenty-two adult patients with drug-resistant partial-onset seizures were included. After a 3-month baseline period, patients received dapsone 100 mg per day, for a 3-month evaluation period. Plasma concentrations of anti-epileptic drugs (AEDs) did not significantly change during the study. No alteration of mean clinical laboratory values was observed. The reported adverse events were: mild methemoglobinemia (50%), headache (31.8%), paleness (27.3%) and somnolence (4.5%).Sixteen of 22 patients reduced their seizure frequency in more than 50% as a result of dapsone treatment. Three subjects remained seizure-free during the entire dapsone treatment period. This open-label study of adjunctive dapsone therapy at 100 mg/day suggests that dapsone is safe, and well-tolerated in adults with drug-resistant partial-onset seizures.

High prevalence of Dapsone-induced oxidant hemolysis in North American SCT recipients without glucose-6-phosphate-dehydrogenase deficiency

Dapsone (4-4'-diaminodiphenylsulfone) is commonly used for Pneumocystis jirovecii pneumonia (PCP) prophylaxis in immunocompromised patients. Oxidant hemolysis is a known complication of dapsone, but its frequency in adult patients who have undergone a SCT for hematological malignancies is not well established. We studied the presence of oxidant hemolysis, by combining examination of RBC morphology and laboratory data, in 30 patients who underwent a SCT and received dapsone for PCP prophylaxis, and compared this group with 26 patients who underwent a SCT and received trimethoprim-sulfamethoxazole (TMP-SMX) for PCP prophylaxis. All patients had normal glucose-6-phosphate dehydrogenase (G6PDH) enzymatic activity. In SCT patients, dapsone compared with TMP-SMX for PCP prophylaxis was associated with a high incidence of oxidant hemolysis (87 vs 0%, P<0.001), and the morphological evaluation of oxidant hemolysis correlated well with laboratory evidence of hemolysis. Dapsone-induced oxidant hemolysis in SCT patients is 20-fold higher than the reported rate in the population of HIV-infected patients, and thus much higher than the prevalence of G6PDH variants in the general population. In our patients, it manifested clinically as a lower Hb that was not significant enough to result in increased packed RBC transfusions.

Dapsone inhibits IL-8 secretion from human bronchial epithelial cells stimulated with lipopolysaccharide and resolves airway inflammation in the ferret

BACKGROUND

IL-8 is an important activator and chemoattractant for neutrophils that is produced by normal human bronchial epithelial (NHBE) cells through mitogen-activated protein kinase (MAPK) and nuclear factor-κB (NF-κB) p65 pathways. Dapsone, a synthetic sulfone, is widely used to treat chronic neutrophil dermatoses. We investigated the effects of dapsone on polarized IL-8 secretion from lipopolysaccharide (LPS)-stimulated NHBE cells and further evaluated its ability to decrease LPS-induced inflammation in the ferret airway.

METHODS

NHBE cells were grown at air-liquid interface (ALI) to ciliated differentiation. Baseline and endotoxin (LPS)-stimulated IL-8 secretion was measured by enzyme-linked immunosorbent assay at air and basal sides with and without dapsone. Western blotting was used to determine signaling pathways. In vivo, ferrets were exposed to intratracheal LPS over a period of 5 days. Once inflammation was established, oral or nebulized dapsone was administered for 5 days. Intraepithelial neutrophil accumulation was analyzed histologically, and mucociliary transport was measured on the excised trachea.

RESULTS

Dapsone, 1 μg/mL, did not influence unstimulated (basal) IL-8 secretion. Apical LPS stimulation induced both apical and basolateral IL-8, but basolateral LPS increased only basolateral IL-8. Dapsone inhibited polarized IL-8 secretion from ALI-conditioned cells. Dapsone also decreased LPS-induced IL-8 mRNA level. LPS led to phosphorylation of extracellular signal-regulated kinase 1/2, but not p38 MAPK or c-Jun NH(2)-terminal kinase. LPS also induced NF-κB p65 phosphorylation, an effect that was inhibited by dapsone. Both oral and aerosol dapsone decreased LPS-induced intraepithelial neutrophil accumulation, but only treatment with aerosol dapsone restored mucociliary transport to normal.

CONCLUSIONS

Dapsone, given either systemically or as an aerosol, may be useful in treating neutrophilic airway inflammation.

Innovative use of dapsone

After synthesis of dapsone (4,4' diaminodiphenylsulfone) in 1908, the compound was known exclusively in chemistry. Following the epoch-making discovery of the antimicrobial potential for sulfonamides emerged, the sulfone class was included in the medical armamentarium. The therapeutic role of sulfones related to both pathogen-caused diseases and chronic inflammatory dermatoses has led to extensive use in dermatology. At present dapsone is the only sulfone congener available for clinical practice. The sulfone is used in rifampin-based multiple-drug regiments to treat multibacillary and paucibacillary leprosy and to treat Pneumocystis jiroveci pneumonia and prevent toxoplasmosis in individuals with AIDS. In dermatology, dapsone is the preferred drug for treating dermatitis herpetiformis (Duhring's disease) and is useful in the management of a broad range of chronic inflammatory entities, especially autoimmune bullous disorders. With proper administration and monitoring, the sulfone should be considered a useful and safe agent.

Guidelines in dermatology--quo vadis?: Facts and controversies

Since their introduction in 1980s, medical guidelines have become a milestone in the modern medical practice and science. Being a key feature of modern evidence-based medicine, guidelines offer the opportunity for unification and standardization of diagnostic procedures, their use guarantees the equal access of patients to medical service, and they represent a scaffold for inexperienced physicians. The implementation of guidelines also can serve as a basis in malpractice issues and can contribute to the formation of national and international health care policies. In past decades, the process of development, update, and practical application of clinical guidelines has been seriously improved; however, certain limitations still exist, namely cost-effectiveness issues, editorial independence, applicability, accessibility, and external validity. This contribution discusses the advantages and the drawbacks in the use and the development of medical guidelines, emphasizing future perspectives and challenges in the development of clinical guidelines.

Emerging drugs for acne

Acne vulgaris is a common skin disorder that affects most individuals at some point in their lives. It may result in significant morbidity, including cutaneous scarring and psychological impairment. Current treatments include topical retinoids, benzoyl peroxide, topical and systemic antibiotics, and systemic isotretinoin. There are growing concerns of rising antibiotic resistance, significant side effects of isotretinoin therapy, and lack of safe and effective treatment for pregnant females. Recent advances in the pathogenesis of acne have led to a greater understanding of the underlying inflammatory mechanisms and the role the Propionibacterium acnes and biofilms. This has led to the development of new therapeutic targets. This article reviews emerging treatments of acne, including topical picolinic acid, topical antibiotic dapsone, systemic zinc salts, oral antibiotic lymecycline, new formulations of and synergistic combinations of benzoyl peroxide, photodynamic therapy with topical photosensitizers and potential acne vaccines.

Treatment of acne vulgaris: a literature review / Lečenje običnih akni (acne vulgaris) – pregled literature

Acne vulgaris is a common skin disease, which affects individuals of all races and ages. In Caucasians, almost 85% of individuals between 12 and 25 years, as well as 25% of adults, are affected with some forms of acne. The pathophysiology of acne is multifactorial, and thus, the treatment must cover all the possible causes of acne. For this reason, acne therapy is mostly a combination therapy, with the main goal to achieve clinical improvement, without scarring and residuals, as much as possible. The treatment should be planned individually, depending on the clinical appearance, severity and psychological profile of the patient. The treatment usually takes time and requires dedication and patience of both the patient and the physician.

Efficacy of dapsone in the treatment of pemphigus and pemphigoid: analysis of current data

Dapsone is a chemotherapeutic agent primarily used in treating leprosy, Pneumocystis jiroveci (previously carinii) pneumonia, and malaria. It is also used as an adjuvant in the treatment of pemphigus and pemphigoid. To assess the role of dapsone in the treatment of pemphigus and pemphigoid, a retrospective review of reports in the English-language literature was conducted. Information on the number of patients treated, their average age, prior therapies, indications for use, protocol (dose and interval) used, concomitant therapies, reported adverse effects, and clinical outcomes were analyzed. There were 35 case reports/series published describing the use of dapsone in a total of 427 patients. Data on 55 pemphigus patients were obtained from several case reports and some case series and one randomized controlled trial. Of these, 32 patients with pemphigus vulgaris and 14 patients with pemphigus foliaceus responded to dapsone. Data from 13 case series, each including at least five patients, accounted for 372 patients with pemphigoid. The overall response rates to dapsone, when given either alone or in combination with corticosteroids or immunosuppressive agents, were 84% in mucous membrane pemphigoid, and 81% in bullous pemphigoid. Hemolysis was the most common adverse effect observed. Dapsone is a promising and useful agent in patients with autoimmune mucocutaneous blistering diseases, especially in mucous membrane pemphigoid. It can be used as a corticosteroid-sparing agent. Therefore, its combined use with oral corticosteroids may be useful in pemphigus vulgaris and bullous pemphigoid. Adverse effects of dapsone are dose dependent and usually reversible. Hemolysis and concomitant anemia secondary to hemolysis are expected in most patients. In the opinion of the authors, dapsone is underutilized in the treatment of autoimmune mucocutaneous blistering diseases.

Complete atrioventricular block associated with dapsone therapy: a rare complication of dapsone-induced hypersensitivity syndrome

Dapsone is still widely used for a range of infectious and inflammatory diseases. A potential severe side-effect, known as dapsone-induced hypersensitivity syndrome (DHS), may occur. DHS is characterized by fever, skin rashes, lymphadenopathy and multiorgan dysfunction manifesting as hepatitis, cholangitis, pneumonitis, colitis, thyroiditis and myocarditis. However, DHS-associated complete atrioventricular block has not previously been reported. We describe here a 45-year-old Chinese woman who developed DHS after 5 weeks of dapsone therapy for pustular palmoplantar psoriasis. In addition to typical DHS symptoms, she experienced several episodes of syncope as a result of complete atrioventricular block which was successfully reversed with a permanent pacemaker implantation.

Dapsone 5% gel: a review of its efficacy and safety in the treatment of acne vulgaris

Dapsone, a synthetic sulfone that has been available for over 60 years, has been used to treat a myriad of cutaneous disorders. Prior to the general acceptance of isotretinoin, oral dapsone had been reported to be effective in the treatment of nodulocystic acne. However, the potential for systemic toxicity prevented its widespread adoption in the treatment of acne. For many years scientists explored the possibility of developing a topical formulation of dapsone for the treatment of acne in the hope of minimizing the adverse hematologic effects of oral dapsone. Such a formulation had been unavailable until recently. Dapsone 5% gel (Aczone) was recently developed to treat acne vulgaris. This topical formulation was approved in the US based on two randomized, vehicle-controlled studies. A 12-month, open-label study was also conducted to assess the safety and efficacy of topical dapsone over the long term. Finally, two open-label phase I pharmacokinetic studies were conducted to evaluate the systemic absorption of topical dapsone compared with oral dapsone. This article reports the results of these studies, which show a reduction in acne lesion count comparable to those observed in clinical trials of other approved topical acne therapies. With regard to safety, the studies demonstrated that the concentrations of dapsone and N-acetyl dapsone remain low and do not accumulate over time once steady state is reached. Of the total of 50 patients with glucose-6-phosphate dehydrogenase (G6PD) deficiency in all the studies, only two experienced a drop in hemoglobin levels, and those shifts in values were consistent with fluctuations observed for other study participants. A recent study evaluating the risk of hemolysis in patients with G6PD deficiency found topical dapsone 5% gel to be safe to use in this patient population. Based on the observations noted in the above-mentioned studies, we conclude that topical dapsone 5% gel is safe and effective in the treatment of acne vulgaris.

[Cutis verticis gyrata-like acne inversa. Combined medical and surgical management]

A 22-year-old soldier developed during his assignment in Afghanistan purulent draining nodules and fistulas on the scalp. The clinical picture resembled an inflammatory variant of cutis verticis gyrata, and taken together with the histology the diagnosis of acne inversa of the scalp was established. Therapy was started with corticosteroids and isotretinoin, which stopped the secretion of pus: thereafter all there nodules and draining sinuses were excised. After surgery, medication was continued with low dose isotretinoin and dapsone. A complete healing was achieved with this combined regimen.

Antioxidant, antiinflammatory and antiapoptotic effects of dapsone in a model of brain ischemia/reperfusion in rats

Although dapsone (4,4'-diaminodiphenylsulfone) has been described as a neuroprotective agent in occlusive focal ischemia in rats, its mechanism of action is still unknown. To explore this mechanism, oxidative, inflammatory and apoptotic processes were evaluated in the striatum of adult rats using a model of ischemia-reperfusion (I/R), either with or without dapsone treatment. Male Wistar rats were submitted to transient middle cerebral artery occlusion for 2 hr, followed by reperfusion. Rats were dosed either with dapsone (12.5 mg/kg i.p.) or vehicle 30 min before or 30 min after the ischemia onset. Lipid peroxidation (LP) and nitrotyrosine contents were measured 22 hr after reperfusion, and myeloperoxidase activity was evaluated 46 hr after I/R. Different markers for apoptosis and necrosis were also evaluated both at 24 and 72 hr after I/R experimental procedure. LP increased by 37% in ischemic animals vs controls, and this effect was reversed by dapsone treatments. A similar effect was observed regarding nitrotyrosine striatal contents. Myeloperoxidase activity, a marker of inflammatory response, increased 3.7-fold in ischemic animals vs. control rats, and dapsone treatment antagonized that effect. Although apoptosis was increased by the effect of ischemia at both evaluation times, dapsone antagonized that effect only at 72 hr after surgery. Dapsone antagonized all of the I/R end points measured, showing a remarkable ability to decrease markers of damage through antioxidant, antiinflammatory, and anti-apoptotic effects.

Nonstandard and off-label therapies for psoriasis

Although most psoriasis patients respond to standard therapies, many circumstances warrant the use of nonstandard or off-label treatments. For instance, patients with treatment-resistant psoriasis or those who have had multiple adverse effects to other therapies may be good candidates for off-label treatments. Similarly, patients with unusual and hard-to-treat forms of psoriasis such as pustular psoriasis and palmoplantar psoriasis or specific comorbidities may benefit from certain nonstandard therapies. Drugs that may be used as alternatives to standard therapies include mycophenolate mofetil, tacrolimus or pimecrolimus, isotretinoin, colchicine, sulfasalazine, paclitaxel, dapsone, azathioprine, and hydroxyurea. Other unconventional therapies include climatotherapy at the Dead Sea and grenz ray therapy.

Dapsona como alternativa no tratamento de urticária crônica não responsiva a anti-histamínicos

FUNDAMENTOS: A urticária crônica é dermatose que interfere negativamente na qualidade de vida de seus portadores. O tratamento clássico com anti-histamínicos muitas vezes é ineficaz. OBJETIVO: Avaliar a eficácia e a segurança do uso da dapsona no tratamento da urticária crônica não responsiva a anti-histamínicos. METÓDOS: Realizou-se estudo retrospectivo mediante a revisão de prontuários de pacientes atendidos em ambulatório especializado em urticária entre novembro de 1996 e março de 2007. RESULTADOS: Foram avaliados 20 pacientes com urticária crônica de difícil controle, que receberam tratamento com dapsona na dose de 100mg/dia. Associados à dapsona, foram mantidos anti-histamínicos em altas doses, que, isoladamente, não controlavam os sintomas. Quatorze pacientes (70%) responderam com melhora do quadro, observada tanto na diminuição ou desaparecimento das lesões quanto na redução do prurido; três (15%) não obtiveram nenhum sucesso com a medicação; e três (15%) tiveram o tratamento suspenso em decorrência de efeitos colaterais. CONCLUSÃO: Neste estudo, conclui-se que a dapsona é opção segura e eficaz para pacientes com urticária crônica grave não responsiva a anti-histamínicos.

Urticaria unresponsive to antihistaminic treatment: an open study of therapeutic options based on histopathologic features

BACKGROUND

The non- or low-sedating H1 receptor antagonists represent the basic therapy for urticaria.

OBJECTIVE

To test an alternative approach to patients unresponsive to conventional treatment.

MATERIALS AND METHODS

A total of 22 patients with chronic urticaria unresponsive to conventional antihistamine treatment were enrolled for this study. They had uncontrolled urticaria even using multiple combinations of antihistamines on maximum doses and corticosteroids in short cycles (prednisone 20-40 mg, per os once a day, 3-7 days per month). Cutaneous biopsies of the urticaria lesions were taken. These findings were classified as: (I) a mixture of perivascular dermal inflammatory infiltrate composed of lymphocytes, monocytes and neutrophils and/or eosinophils; (II) inflammatory infiltrate composed chiefly of neutrophils; and (III) inflammatory infiltrate composed mainly of eosinophils. According to histology, the patients were submitted to one of the following therapeutic schemes: class A - antihistamine treatment plus dapsone; class B - colchicine or dapsone; class C - montelukast.

RESULTS

Four patients in class A, 08 in class B and seven in class C displayed complete control of urticaria after 12 weeks of treatment; one patient in class B and two in class C did not respond to treatment. Two years after discontinuation, 16 patients are still free of urticaria.

CONCLUSIONS

This study suggests an alternative approach for treating unresponsive chronic urticaria.

A case of precocious emphysema and lung cancer in a woman with a history of hypocomplementemic urticarial vasculitis

Severe emphysema developed in a white woman with a 26-pack-year history of tobacco use. Serum alpha(1)-antitrypsin levels were normal. A history of autoimmune hemolytic anemia, angioedema, low complement, and recurrent urticaria prompted an immunologic workup that ultimately led to a diagnosis of hypocomplementemic urticarial vasculitis syndrome. Treatment with oral prednisone and inhaled bronchodilators improved symptoms, but 4 months after diagnosis non-small cell lung cancer was discovered and she ultimately died. Hypocomplementemic urticarial vasculitis is an uncommon cause of precocious emphysema and has not previously been reported in a patient with bronchogenic carcinoma.

Infliximab for the treatment of disseminated pyoderma gangrenosum associated with ulcerative colitis. Case report and literature review

We report the case of a 19-year-old woman who developed an acute disseminated pyoderma gangrenosum (PG) during a severe flare of ulcerative colitis (UC). She was successfully treated with a 3-dose regimen of the anti-tumor-necrosis-factor-alpha antibody infliximab. The literature on the effectiveness of this biological agent was reviewed, including 8 other cases of UC-associated PG and 77 cases of Crohn's-disease-associated PG. This case report and the review of the literature demonstrate that infliximab can be successfully used to treat patients with PG associated with inflammatory bowel diseases.

Neuroprotective effect of dapsone in patients with acute ischemic stroke: a pilot study

OBJECTIVES

In a previous study of brain ischemia in rats, dapsone (4,4'-diamino-diphenylsulfone) was associated with a neuroprotective effect. As dapsone is safe and relatively free of adverse reactions, we conducted a pilot clinical trial to assess the possibility of using this drug in patients with a cerebral infarction.

METHODS

A double-blind, placebo-controlled, pilot clinical trial of dapsone was conducted from January 1999 to January 2000. Thirty patients with a CT or MRI documented ischemic stroke in the territory of the middle cerebral artery were included. Patients with >4 points of the National Institute of Health Stroke Scale (NIHSS) were randomly allocated to receive either a single dose of 200 mg dapsone or placebo. For follow-up, NIHSS on days 0, 2, 7 and 60, modified Rankin scale and Barthel index at day 60 were applied. Adverse reactions were also recorded. The main cut point was considered when a patient obtained a variation of 2 points for modified Rankin scale and 17 points for Barthel index.

RESULTS

Fifteen patients received dapsone and 15 received placebo. Twenty-nine were followed up for 60 days and one patient in the treatment group died during follow-up. Favorable scores were achieved for treated patients by all different measures; NIHSS (p=0.032), Barthel (p=0.049) and Rankin scale (RR=0.182, 95% CI: 0.04 and 0.86). Best results were obtained when treatment started within the first 8-10 hours after stroke. No adverse reactions related to medication were reported.

DISCUSSION

Dapsone appears as a useful and safe drug for the treatment of stroke patients. Results of this pilot trial are promising and support further research to define the role of dapsone as a neuroprotective drug.

Two randomized studies demonstrate the efficacy and safety of dapsone gel, 5% for the treatment of acne vulgaris

BACKGROUND

A new aqueous gel formulation of dapsone has been developed that allows clinically-effective doses of dapsone to be administered topically with minimal systemic absorption.

OBJECTIVES

The goal of these studies was to evaluate the efficacy and safety of dapsone gel, 5% in the treatment of acne.

METHODS

Patients 12 years of age and older with acne vulgaris (N = 3010) participated in two identically-designed 12-week, randomized, double-blind studies of twice-daily monotherapy with dapsone gel, 5%, versus a vehicle gel.

RESULTS

Dapsone gel-treated patients achieved superior results in terms of the investigator's global acne assessment (P < .001) and the mean percentage reduction in inflammatory, noninflammatory, and total lesion counts (all, P < .001) at week 12. Reductions in inflammatory lesion counts favoring dapsone gel over vehicle were apparent as early as 2 weeks and reached statistical significance by 4 weeks. No clinically significant changes in laboratory parameters, including hemoglobin, even among glucose-6-phosphate dehydrogenase-deficient patients, were observed. Adverse events were comparable between the treatment groups and rarely led to discontinuation.

LIMITATIONS

Adjunctive topical treatments and their impact on acne were not studied in this trial.

CONCLUSIONS

Dapsone gel, 5% appears to be an effective, safe, and well-tolerated treatment for acne vulgaris, with a rapid onset of action.

A double blind randomised placebo controlled pilot study of oral co-trimoxazole in advanced fibrotic lung disease

BACKGROUND

In 1996, clinical improvement with oral co-trimoxazole was noted in a patient with biopsy proven advanced fibrotic lung disease who was awaiting a lung transplant. Subsequently, 14 patients with end stage fibrotic lung disease also responded to oral co-trimoxazole. This prompted a double blind randomised placebo controlled pilot study in patients with advanced stages of idiopathic interstitial pneumonias (IIP) to objectively measure benefit.

PATIENTS

Twenty patients (aged 49-84 years; 11 males) with progressive fibrotic lung disease who had differing subtype diagnosis from CT scans of progressive fibrotic IIP, and showed oxygen desaturation on exertion were selected.

METHOD

A detailed assessment of arterial gases, lung function, and progressive shuttle-walking tests combined with oxygen saturation monitoring. Quality of life data was recorded. Randomisation was to co-trimoxazole or identical placebo for 3 months followed by 6 weeks of pulmonary rehabilitation before decoding. Placebo patients received active treatment upon decoding with continued follow up of all patients.

MAIN OUTCOME MEASURES

Primary 1. Shuttle walking test. Secondary 2. FVC and quality of life.

RESULTS

Active treatment showed a significant improvement in shuttle walking test from 255 to 355 m (p=0.002) (95% CI 200-450) with reduced oxygen desaturations during exercise (p=0.003). FVC improved on treatment (+21%) from median 1.9 to 2.3 L (p=0.05) (95% CI 1.3-3.0) but TLC and DLCO were not significantly changed although stable at 12 months. The MRC 5 Point Dyspnoea Score showed improvement (p=0.05) at 3 months for the active group which was maintained at 12 months. The SGHRQ showed a significant reduction in symptom scores at 12 months (p=0.05). The placebo group showed no significant change in any parameters, but demonstrated identical improvement following oral co-trimoxazole. Serum vascular endothelial growth factor (VEGF) was reduced 50% in the active group at 3 months, but just failed to reach statistical significance. 'Out of study' HRCT scans in 12 patients showed significant reduction in ground glass changes (p=0.05) after 12 months of continuous co-trimoxazole treatment.

CONCLUSION

The findings of the pilot study show significant improvements in objective and subjective parameters which fulfil the ATS/ERS (2000) criteria of 'a favourable response to treatment'.

Pharmacokinetics of Dapsone Gel, 5% for the Treatment of Acne Vulgaris

BACKGROUND

Oral dapsone has been available for over 60 years and has been used to treat severe acne vulgaris; however, the oral formulation is known to cause dose-dependent haematological reactions and is currently indicated only for diseases such as dermatitis herpetiformis and Hansen's disease. A gel formulation of dapsone was recently developed to treat acne vulgaris. As dapsone is administered topically, it was expected that systemic absorption would be considerably lower than that observed with oral dapsone therapy, thereby avoiding any adverse haematological effects.

OBJECTIVE

To report the pharmacokinetic profile of topically applied dapsone gel, 5% in the treatment of acne vulgaris.

STUDY PARTICIPANTS AND METHODS

Three prospective, open-label studies enrolled a total of 548 subjects with acne vulgaris: two phase I pharmacokinetic studies (crossover and drug interaction) and one phase III long-term safety study. In the crossover study (n = 18), topical dapsone gel applied twice daily for a total of 14 days to 22.5% of the body surface area was compared with a single dose of oral dapsone 100mg (the typical clinical dose). In the drug-interaction study (n = 24), oral trimethoprim/sulfamethoxazole monotherapy, topical dapsone gel monotherapy and the two in combination were used twice daily for 7, 21 and 7 days, respectively. In the long-term safety study (n = 506), topical dapsone gel was applied twice daily to acne-affected areas for up to 12 months. Blood samples were drawn at various timepoints in each study to assess drug and metabolite concentrations. Systemic concentrations of dapsone, N-acetyl dapsone, dapsone hydroxylamine, trimethoprim and sulfamethoxazole were determined, according to the study design.

RESULTS

In the crossover study, the mean area under the plasma concentration-time curve (AUC) from 0 to 24 hours for dapsone was 417.5 ng x h/mL after 2 weeks of dapsone gel therapy (n = 10), compared with an AUC from time zero to infinity of 52,641 ng x h/mL after a single dose of oral dapsone; this represents a 126-fold lower systemic exposure for dapsone gel at typical therapeutic doses. In the drug-interaction study, the AUC from 0 to 12 hours for dapsone was 221.52 ng x h/mL after 3 weeks of dapsone gel monotherapy compared with 320.3 ng x h/mL after 1 week of coadministration with trimethoprim/sulfamethoxazole. In the long-term safety study, the mean plasma dapsone concentrations ranged from 7.5 to 11 ng/mL over 12 months. Overall, total systemic exposures to dapsone and its metabolites were approximately 100-fold less for dapsone gel than for oral dapsone, even in the presence of trimethoprim/sulfamethoxazole. There were no reports of any haematological adverse events.

CONCLUSIONS

Topical application of dapsone gel in various settings ranging from 2 weeks to 12 months resulted in systemic exposures to dapsone and its metabolites that were approximately 100-fold less than those after oral dapsone at a therapeutic dose level. The concentrations of dapsone and its metabolites reached steady state and did not increase during prolonged treatment.

Biological evaluation of sulfone derivatives as anti-inflammatory and tumor cells growth inhibitory agents

A variety of sulfone derivatives including three dimethyl arylsulfonyl malonates (1-3), two bis-(arylethenesulfonyl)-vinyl benzenes (4 and 5) and a sulfone triazole (6) were evaluated for their anti-inflammatory as well as tumor cells growth inhibitory activities in vitro. The sulfone derivatives 1, 2, 3 and 6 significantly and dose-dependently inhibited the production of inflammatory mediators such as nitric oxide (NO), and cytokines (tumor necrosis factor (TNF)-alpha and interleukin (IL)-12), in lipopolysaccharide (LPS) and interferon (IFN)-gamma activated murine peritoneal macrophages, without displaying cytotoxicity. The inhibitory mechanism is found through reducing iNOS protein expression. In addition, the derivatives 1-3 significantly arrest mitogen-stimulated spleen cells in G0/G1 stage, whereas compounds 4-6 blocked the same in the G2/M phase. Furthermore, the sulfone derivatives 3 and 6 showed dramatically reduction in the ratio of IFN-gamma to IL-4 production from mitogen-stimulated spleen cells. On the other hand, the novel compounds exhibited interesting cytotoxic activities against a panel of cell lines, particularly, 20 muM of compound 3 showed 50% cytotoxic effect on human hepatoma cell line, but has no effect on normal human peripheral blood mononuclear cells. In conclusion, compound 3 showed interesting anti-inflammatory and tumor cells growth inhibitory functions.

[Disulone and hepatosiderosis]

BACKGROUND

Disulone (dapsone + iron oxalate) is a sulfone used in the treatment of numerous skin diseases. We report two cases of hepatosiderosis secondary to long-term administration of Disulone.

PATIENTS AND METHODS

Case n degrees 1. A 51-year-old man was treated with Disulone for a neutrophilic skin disease. After 17 years of treatment, elevated serum ferritin and free iron with hemolysis were found. Liver biopsy confirmed hepatosiderosis. A diagnosis of genetic hemochromatosis was ruled out by the absence of C282Y mutation of the HFE gene. Case n degrees 2. A 52-year-old man receiving Disulone for dermatitis herpetiformis for 25 years presented elevated serum ferritin and free iron with hemolysis. Hepatic iron overload was confirmed by liver biopsy. The absence of C282Y mutation (HFE gene) ruled out a diagnosis of genetic hemochromatosis.

DISCUSSION

In our two cases, hepatosiderosis was noted after long-term administration of Disulone. This complication has been reported only rarely. In murine models, a relationship was found between prolonged administration of dapsone and hepatic iron overload as revealed by hemolysis. Although it is difficult to extrapolate this relationship to humans with any certainty, our patients had also chronic hemolysis and iron overload secondary to administration of Disulone. Moreover in France, dapsone is marketed in combination with iron oxalate, with the attendant risk of iron overload. These cases raise the question of the need for serum ferritin analysis during Disulone therapy.

The Dapsone hypersensitivity syndrome revisited: a potentially fatal multisystem disorder with prominent hepatopulmonary manifestations

4,4'-Diaminodiphenylsulphone (Dapsone) is widely used for a variety of infectious, immune and hypersensitivity disorders, with indications ranging from Hansen's disease, inflammatory disease and insect bites, all of which may be seen as manifestations in certain occupational diseases. However, the use of dapsone may be associated with a plethora of adverse effects, some of which may involve the pulmonary parenchyma. Methemoglobinemia with resultant cyanosis, bone marrow aplasia and/or hemolytic anemia, peripheral neuropathy and the potentially fatal dapsone hypersensitivity syndrome (DHS), the focus of this review, may all occur individually or in combination. DHS typically presents with a triad of fever, skin eruption, and internal organ (lung, liver, neurological and other systems) involvement, occurring several weeks to as late as 6 months after the initial administration of the drug. In this sense, it may resemble a DRESS syndrome (Drug Rash with Eosinophilia and Systemic Symptoms). DHS must be promptly identified, as untreated, the disorder could be fatal. Moreover, the pulmonary/systemic manifestations may be mistaken for other disorders. Eosinophilic infiltrates, pneumonitis, pleural effusions and interstitial lung disease may be seen. This syndrome is best approached with the immediate discontinuation of the offending drug and prompt administration of oral or intravenous glucocorticoids. An immunological-inflammatory basis of the syndrome can be envisaged, based on the pathological picture and excellent response to antiinflammatory therapy. Since dapsone is used for various indications, physicians from all specialties may encounter DHS and need to familiarize themselves with the salient features about the syndrome and its management.

Methemoglobinemia associated with dapsone therapy in a child with pneumonia and chronic immune thrombocytopenic purpura

This report describes a case of methemoglobinemia in association with dapsone therapy. The patient, an immunocompromised child with chronic immune thrombocytopenic purpura, presented with fever, cough, perioral cyanosis, bilateral lower lobe rales, and low O2 saturation by pulse oximetry (89%). His medications included prednisone and rituximab for chronic immune thrombocytopenic purpura, and dapsone for Pneumocystis carinii pneumonia prophylaxis. Because of his lack of dyspnea and tachypnea, and the temporal association of his perioral cyanosis with the initiation of dapsone therapy, a methemoglobin (MetHb) level was obtained and found to be elevated at 9.6%. The authors discuss the mechanism and treatment of methemoglobinemia secondary to dapsone. They also stress the importance of monitoring for signs and symptoms of methemoglobinemia in immunocompromised patients on dapsone therapy for P. carinii pneumonia prophylaxis.

Hypereosinophile Dermatitis

BACKGROUND

The idiopathic hypereosinophilic syndrome is a rare systemic disease characterized by blood and tissue eosinophilia of unknown etiology, in which multiple organs may be affected. In hypereosinophilic dermatitis the only affected organ besides the blood is the skin.

PATIENTS

We present a series of seven patients with hypereosinophilic dermatitis who were treated in our hospital between 2002 and 2003.

RESULTS

All patients initially showed characteristic, therapy-resistant, polymorphic skin lesions, presenting with a combination of erythematous, pruritic and urticarial papules and plaques. All had blood eosinophilia without evidence of allergic, parasitic or other causes. The histology showed tissue eosinophilia only in half of the cases; the other histological findings were non-specific. We observed a good response to therapy with systemic corticosteroids, dapsone and light therapy, applied as UVA-1 irradiation or as shower photochemotherapy.

CONCLUSIONS

The diagnosis "hypereosinophilic dermatitis" should be based primarily on the characteristic clinical picture together with "idiopathic" peripheral eosinophilia, whereas the histological findings are not always indicative. Because of the multiplicity of possible differential diagnoses and the often non-revealing histology, we assume that the diagnosis "hypereosinophilic dermatitis" is often overlooked.