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At least 703 records · Page 39Linked to original sources
PubMed1982

Dapsone-responsive, noninfectious verrucous pyoderma. Its occurrence following cisplatin therapy.

A nodular, centrally verrucous, noninfectious pyoderma of the dorsal aspects of the hands and fingers developed in a 66-year-old man with metastatic bladder carcinoma after palliative cisplatin therapy. The dermatosis was clinically similar to erythema elevatum diutinum but biopsy failed to show substantial leukocytoclastic vasculitis. The eruption responded to dapsone. The role of cisplatin in the induction of the dermatosis is speculative.

Aged↗
PubMed1980

Erythema multiforme bullosum due to dapsone.

Two cases of tuberculoid leprosy who developed erythema multiforme bullosum (EMB) due to Dapsone (DDS) is reported. Burning and itching sensations were found to be the prominent prodromal symptoms. The patients gave history of urticaria and bronchial asthma. Salient clinical features and further management of the cases by desensitization with slow induction to DDS under cover of steroids and antihistamines have been discussed.

Adult↗
PubMed1995

Activity of combinations of dapsone, rifampin, minocycline, clarithromycin, and sparfloxacin against M. leprae-infected mice.

In these studies we evaluated the activity of low levels of five antimicrobials against Mycobacterium leprae-infected mice when administered singly and in all possible two- and three-drug combinations. Antibiotics studied were: dapsone (D) 0.0001% in the diet, rifampin (R) 20 mg/kg by gavage once monthly, minocycline (M) 0.004% in the diet, clarithromycin (C) 0.001% in the diet, and sparfloxacin (S) 5 mg/kg by gavage five times weekly. Singly each agent was found bacteriostatic (D + R) or partially bactericidal (M, C, and S) but not fully bactericidal. All 10 two-drug regimens were found at least bacteriostatic, 2 being "partially bactericidal" and 4 being "fully bactericidal." Of the 10 three-drug regimens, 9 were found "fully bactericidal" and the other "partially bactericidal." We conclude that combinations of antibiotics active against M. leprae are generally additive in combination.

Animals↗
PubMedDate not supplied

[Sensitivity to dapsone, sulfamethoxypyridazine and ethionamide of mycobacterium leprae taken from patients treated by the drugs].

Suspensions of M. leprae from skin biopsies of patients treated with dapsone (DDS) (four cases), sulfamethoxypyridazine (SMP) (six cases), and ethionamide (ETH) (seven cases), were inoculated into mouse foot pads and their sensitivity for the different drugs determined. Two strains were DDS resistant. Resistance appeared after 13 and 14 years respectively after the start of treatment. Five strains were isolated from patients treated with SMP. Relapses during sulfonamide treatment are considered to be due to the low effective serum concentrations reached by SMP, a situation which is aggravated by irregularities in drug intake. Fortunately all strains were sensitive to SMP and DDS as well. Four strains were ETH resistant. ETH resistance at the present moment reaches 4% and appeared in two cases six years after the start of treatment. It is concluded that SMP is not indicated for the treatment of multibacillary leprosy and that ETH can be used only in association with other drugs during the introductory phase of treatment of multibacillary forms of leprosy.

Animals↗
PubMedDate not supplied

Evidence that the biotransformation of dapsone and monoacetyldapsone to their respective hydroxylamine metabolites in rat liver microsomes is mediated by cytochrome P450 2C6/2C11 and 3A1.

The formation of dapsone hydroxylamine (DDS-NOH) and monoacetyldapsone hydroxylamine (MADDS-NOH) was found to be greater in male vs. female rat liver microsomes, suggesting a role for either CYP2C11 or CYP3A2. Preincubation with cimetidine (selective for inhibition of CYP2C11), but not troleandomycin (selective for inhibition of CYP3A1/2), inhibited metabolite formation. Furthermore, incubation with monoclonal antibodies (Mabs) to CYP2C6/2C11 reduced metabolite formation to below the level of detection. Together, these data indicate that N-hydroxylation of DDS and MADDS in rat liver microsomes from untreated male rats is catalyzed by CYP2C6/2C11. Interestingly, dexamethasone pretreatment increased the hydroxylation of both metabolites. Preincubation with cimetidine or Mabs to CYP2C6/2C11 (at an antibody:protein ratio of 26:1) in microsomes from dexamethasone pretreated animals did not reduce the N-hydroxylation of DDS, whereas preincubation with troleandomycin reduced metabolite formation by > or = 50%. Collectively, these data indicate that the constitutive enzymes CYP2C6 and/or CYP2C11, as well as CYP3A1 (nonconstitutive), are capable of catalyzing the hydroxylation of DDS and MADDS.

Acetylcysteine↗
PubMed1976

Clofazimine in the treatment of dapsone resistant leprosy.

Dapsone resistant patients treated with clofazimine 100 mg daily show a consistent response to treatment. Concern is expressed regarding the prolonged persistence of viable organisms during treatment, with the attendant risk of further resistance developing. The importance of prevention of this problem is discussed.

Clofazimine↗
PubMedDate not supplied

Monoacetyldapsone inhibition of dapsone N-hydroxylation by human and rat liver microsomes.

Dapsone (DDS) is metabolized by N-hydroxylation and N-acetylation to DDS hydroxylamine (DDS-NOH) and monoacetyldapsone (MAD), respectively. The activities of these two alternative and independent reactions vary widely between individuals and show an inverse relationship during chronic DDS therapy. Toxicity observed during DDS therapy has been attributed to DDS-NOH. The observation of reduced toxicity in rapid acetylators, who are also poor hydroxylators, therefore, raised the possibility that MAD may be inhibiting DDS-NOH formation. This hypothesis was tested in human and rat liver microsomes. Human liver microsomes hydroxylated DDS with a lower affinity (KM 2-fold greater) and lower maximal catalytic activity (Vmax 12-fold lower) than that of the rat. The relative catalytic activity (Vmax/KM) was 22-fold higher in rat compared with human liver microsomes. Furthermore, MAD was a potent inhibitor of DDS N-hydroxylation by rat liver microsomes (52% inhibition at 0.01 mM MAD) compared with human liver microsomes (23% inhibition at 0.4 mM MAD). Human, but not rat, liver microsomes deacetylated MAD to DDS by an NADPH independent mechanism. These results show that substantial differences exist in DDS N-hydroxylase between rats and humans, with respect to substrate affinity, enzyme activity, and susceptibility to inhibition, such that information obtained from the rat should not be extrapolated to humans. We conclude that MAD is a potent inhibitor of DDS-NOH formation in rat liver microsomes. The degree of inhibition in human microsomes, however, suggest that MAD is unlikely to be a significant modulator of enzyme activity in vivo.

Animals↗
PubMed1993

Dapsone poisoning.

Two cases of suicidal dapsone ingestion are reported. These patients presented with marked cyanosis and had significant methaemoglobinaemia on admission. One patient also had acute psychosis and haemolytic anaemia. Both patients responded to intravenous methylene blue therapy and nasal oxygen inhalation and recovered without any sequelae.

Adult↗
PubMed1993

Acetylation of dapsone by human whole blood.

We studied the acetylation of dapsone (DDS) in vitro by whole blood taken from subjects with known acetylator phenotype. The acetylation of DDS by whole blood was both incubation time- and DDS concentration-dependent. Thus, it is highly recommended to separate plasma immediately after blood withdrawal during acetylation phenotyping using DDS. para-aminobenzoic acid (PABA) substantially inhibited the acetylation of DDS by whole blood taken from both slow and rapid acetylators, while procainamide (PAD) significantly inhibited DDS acetylation by whole blood taken from slow acetylators. At the highest PAD concentration used (208 microM), DDS acetylation by whole blood taken from rapid acetylators was also inhibited. In contrast, sulphanilamide (SAD) failed to produce any significant inhibition of the acetylation of DDS by whole blood taken from either slow or rapid acetylators. Furthermore, there was no correlation between DDS acetylation by whole blood in vitro and the acetylator status of the subject. It is therefore not possible to predict the acetylator phenotype by studying DDS acetylation by human whole blood. These results indicate that the DDS N-acetyltransferase of human whole blood is most probably of the monomorphic type.

4-Aminobenzoic Acid↗
PubMedDate not supplied

Intracellular localization of dapsone and rifampicin in skin and nerve of multidrug treated leprosy patients.

Intracellular localization of antileprosy drugs dapsone (DDS) and rifampicin (RFP) was carried out on skin and nerve lesions obtained from multidrug treated, multi (BL-LL)- and pauci (BT-TT) bacillary cases of leprosy using immunocytochemical techniques. Intracellular localization of the above drugs especially in macrophages and Schwann cells was aimed by using rabbit raised anti DDS and RFP polyclonal antibody in an indirect peroxidase assay. Our study records both intra and extracellular staining with anti DDS and RFP antibodies in the skin as well as nerve lesions of MB and PB cases treated with MDT. All the nerves under investigation had moderate to severe pathology and hence free diffusion of the drug could be attributed to the broken barrier. Basal lamina around the Schwann cell did not seem to form a barrier. It was also noted that the drug (metabolite) persisted over a long period of time).

Animals↗
PubMed1977

Erythema elevatum diutinum. Response to dapsone.

A patient with a 20-year history is presented as a classic example of erythema elevatum diutinum, with a dramatic response to dapsone therapy, and with interesting features of improvement during pregnancies and occurrence of giant cell tumors of soft tissue, neither of these latter features having been previously reported.

Adult↗
PubMed1976

High dose dapsone toxicity.

A description of the clinical and biochemical course is given for a patient who developed haemolysis and methaemoglobinaemia following dapsone therapy in high dosage for 2 weeks.

Aged↗
PubMed1991

Self-administered dapsone compliance of leprosy patients in eastern Nepal.

Self-administered dapsone intake by leprosy patients in Eastern Nepal was monitored with a urine spot test. Of 341 outpatients 55 (16.1%) were found to be noncompliant. A significant relationship was found between noncompliance and age and between noncompliance and caste. Sex, disease classification, type of treatment, duration of treatment, history of leprosy reactions and travel time to the clinic did not influence the compliance. In remote areas the urine spot test can be useful in leprosy control programmes.

Adolescent↗