Dap sone

Salicylates antagonize probenecid s uricosuric action. Concurrent administration of probenecid increases die effects of acyclovir, barbiturates, benzodiazepines, dap-sone, mediotrexate, NSAIDs, rifampin, and the sulfonamides. 

Agents used for the management of leprosy are dap-sone, rifampicin, clofazimine and recently thalido-... 

If sulfamethoxazole/trimethoprim cannot be continued due to intolerance or severe side effects dap-sone may be given although a small percentage of patients may show cross intolerance. 

Zidovudine should be used cautiously with any other agent that causes bone marrow suppression, such as interferon-a, trimethoprim-sulfamethoxazole, dap-sone, foscarnet, flucytosine, ganciclovir, and valganci-clovir. Probenecid and interferon-p inhibit the elimination of zidovudine therefore, a dosage reduction of zidovudine is necessary when the drugs are administered concurrently. Ribavirin inhibits the phosphorylation reactions that activate zidovudine, and zidovudine similarly inhibits the activation of stavudine thus, the coadministration of zidovudine with ribavirin or stavudine is contraindicated. 

Dapsone [DAP sone] is structurally related to the sulfonamides. It is bacteriostatic for M- leprae, but resistant strains are encountered. Dapsone is also employed in the treatment of Pneumocystis pneumonia in human immunodeficiency virus (HIV) patients. It acts as a... 

When thionamides are used in combination with rifam-picin, hepatotoxicity is more common and severe (18,19). There was a 13% incidence of hepatotoxicity in patients with multibaciUary leprosy treated with dap-sone, rifampicin, and protionamide 10 mg/kg/day, and a 17% incidence in 110 patients treated with dapsone, rifampicin, and protionamide 5 mg/kg/day however, although the lower dose of protionamide did not reduce the incidence of hepatotoxicity, it did reduce its severity (20). Protionamide does not affect the pharmacokinetics of rifampicin (21). 

Krishna DR, Appa Rao AVN, Ramanakar TV, Prabhakar MC. Pharmacokinetic interaction between dap-sone and rifampicin (rifampin) in leprosy patients. Drug Dev Ind Pharm 1986 12 443-9. 

Clofazimine is used in the treatment of lepromatous leprosy. including dap.sone-resistant forms of the di.sca.se. In sidition to its antibacterial action, the drug appears to possess anti-inflammatory and immune-modulating effects that are of value in controlling neuritic complications and in suppressing erythema nodosum leprosum reactions associated with lepromatous leprosy. It is frequently used in combina-iion with other drugs, such as dapsone or rifampin. 

The antibacterial activity and the toxicity of the disubsti-tuted sulfones are thought to be chiefly due to the formation in vivo of dap.sone. Hydrolysis of disubstituted derivatives to the parent sulfone apparently occurs readily in the acid medium of the stomach but only to a very limited extent following parenteral administration. Monosubstituted and nuclear-substituted derivatives are believed to act as entire molecules. 

Dapsone is u.sed in the treatment of both lepromatous and tuberculoid types of lcpro.sy. Dapsone is used widely for all forms of leprosy, often in combination with clofazimine and rifampin. Initial treatment often includes rifampin with dap-.sone. followed by dapsone alone. It is also u.s to prevent the occurrence of multibacillary lcpro.sy when given prophy-lactically. 

Sulphonamides (e.g. sulphamethoxazole and dap-sone) are structural analogues of PABA (Fig. 12.8). They competitively inhibit the incorporation of PABA into dihydropteroic acid and there is some evidence for their incorporation into false folate analogues, which inhibit subsequent metabolism. The presence of excess PABA will reverse the inhibitory action of sulphonamides, as will thymine, adenine, guanine and methionine. However these nutrients are not normally available at the site of infections for which the sulphonamides are used. 

Immunosuppressed radiation victims may also be at risk for reactivation of cytomegalovirus (CMV) and Pneumocystis carinii pneumonia. In a limited casualty situation, if resources are available, clinicians should obtain CMV serology. In addition, patients should have a sensitive assay (antigen assessment or polymerase chain reaction test) every 2 weeks for 30 days postexposure, while those with documented previous CMV exposure should have the assay repeated until 100 days postexposure (2). Patients developing lymphopenia should have a CD4 cell count considered at 30 days postexposure. Those with a CD4 count below 0.2000 x 10 cells L" are at risk for Pneumocystis carinii pneumonia. Physicians should withhold trimethoprim-suha prophylaxis until the leukocyte count is above 3.0 x 10 cells L" or until the absolute neutrophil count is above 1.5 x 10 cells L . Atovaquone, dap-sone and aerosohzed pentamidine are alternative prophylactic agents. Patients should continue prophylactic treatment until the CD4 count reaches or exceeds 0.2000 X 10 cells L, which may occur over several months (2). 

Clofazimine is orally absorbed and accumulates in tissues. Human leprosy from which dap-sone-resistant bacilli have been recovered has been treated with clofazimine with good results. However, unlike dapsone-sensitive microorganisms, in which killing occurs immediately after dapsone is administered, dapsone-resistant strains do not exhibit an appreciable effect until 50 days after initiation of therapy with clofazimine. The daily dose of clofazimine is usually 100 mg. Patients treated with clofazimine may develop red discoloration of the skin. 

Pure red cell aplasia associated with dap-sone therapy. Ann Pharmacother 2005 39 (6) 1137-8. 

Reviews — Mayr s overview of chemotherapy has an excellent section on antibacterial chemotherapy. During the year antituberculous agents from the clinical viewpoint were reviwed, an assessment of isonlazid as a prophylactic was given, and a clinical review.of leprosy chemotherapy was given. The background and clinical activity of the antileprosy phenazine compound B-66, was reviewed by Chang and discussed by him as a vindication of his murine leprosy test. The status of leprosy prophylaxis with dap-sone and with BCG vaccination was discussed. The field of antiseptics and disinfectants was covered by Kretschmer. ... 

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