(Mode of Action of Drugs)

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9.12

Chemotherapy of

Leprosy

Leprosy is caused by Mycobacterium leprae.
The various drugs used in the treatment of
leprosy are classified as in table 9.12.1.

SULFONES

DAPSONE

It is diamino diphenyl sulfone (DDS),
chemically related to sulfonamides, have
been used effectively in the long term treat-
ment of leprosy. Its mechanism of action
is same as that of sulfonamides i.e. inhi-
bition of paraamino benzoic acid

(PABA) incorporation into folic acid (in-

hibition of folate synthesis). In large

proportion of Mycobacterium leprae infec-

tions e.g. in lepromatous leprosy,

resistance can develop, so combination of

dapsone, rifampicin and clofazimine is

used in initial therapy.

After oral administration, it is

completely absorbed and is concentrated in

lepromatous skin, liver, kidney and muscles.

It is metabolized in liver and excreted in

urine as glucuronic acid and sulfate

conjugates.

Table 9.12.1: Classification of drugs used in leprosy.

I. Sulfones

Dapsone (DDS) 100 mg daily

II. Phenazine derivative

Clofazimine (CLOFOZINE) 100 mg TDS

III.Antitubercular drugs

Rifampicin 600 mg monthly/daily

Ethionamide 250 mg daily

IV. Other antimicrobial agents

Quinolones e.g. ofloxacin; 400 mg/day

Others include pefloxacin, sparfloxacin

Macrolides e.g. clarithromycin 500 mg/day

Minocycline 100 mg/day

Chemotherapy of

Leprosy