The Relationship of Dapsone (DDS) Therapy toErythema Nodosum Leprosum. Is it Direct or Indirect?

Abstract

Leprosy Research Un i!, Na tional Leprosy Contra i Ce ntre.Sungei Euloh, Selangor. Ma laysia A double-blind, intemally-controlled clinicaI tr ial is reported of th e effect of dapsone on the severity of erythema nodosum leprosum (EN L) in 17 sulphone resistant lepromatous patients , 16 of whom were suffering from ENL of varying severity . During th e 10 weeks of th e trial, altemative anti-Ieprosy tr eatment was continued unchanged. Dapsone, 100 mg daily in a c.oloured ca psule, was prescribed fo r 14 consecutive days between the th ird and seventh weeks, th e timing being allocated by random distribution, and on th e remaining 56 days an identical placebo capsule was given. The clinicaI severity of the ENL was measured by a number of parameters , and th e intake of ali reaction-suppressing drugs was recorded. No evidence was obtained th at dapsone either immed iately or after an interval, exacerbated or precipitated episodes of ENL. It is concluded that dapsone has no direct ENL-stimulating action per se , but th at ENL results indirect1y , consequent on the drug's chemotherapeutic activity against Mycoba cteri um lepra e.

Evaluation of Treatment of Lepromatous Leprosy Patients in The Netherlands

“…Moreover, the presence of viable M. leprae after treatment with DDS or clofazimine [43] and rifampicin [34] was reported. The conclusion to be drawn is that patients may suffer a relapse due to drug-resistant M. leprae or to the presence of viable M. leprae after discontinuation of treatment.…”

“…Con sequently, there has been a tendency to reduce the dosage of DDS in lepromatous leprosy, in particular in the early stages of treatment. The reaction-provoking effect of DDS, however, was recently challenged by some authors [17,43].…”

Combined Therapy in Leprosy

“…Used in combined therapy, it produces an excellent synergistic action which has not yet been explained in all de tails. The often repeated assertion that dap sone induces leprosy reactions when admin istered in an effective dosage in leprosy treatment, could not be confirmed by us or by other physicians [61].…”

Leprosy reactional states and their treatment

“…If we ignore for the moment the very real existence of dapsone resistant organisms then the treatment of choice for leprosy is dapsone. Despite previous thoughts on the subject there is in 1977 ample evidence that there is never any indication to stop such therapy or to reduce the dosage to below 1-2 mg/kg/day during reactional states (Waters & Helmy, 1974). To do so is to encourage proliferation of the bacillus and so prolong the infection and risk the emergence of dapsone resistant strains.…”