DAPSONEDr samiullah khalil

Fcps (II) Trainee

Dermatology

INTRODUCTION In the early 20th century, it is invented by the

German chemist Paul Ehrlich while working on selective toxicity .

Dapsone (diamino-diphenyl sulfone) is a medication most commonly used in combination with rifampicin and clofazimine as multidrug therapy (MDT) for the treatment of Mycobacterium leprae infections (leprosy). Official in IP,BP,USP.

STRUCTURE4,4’-diaminodiphenylsulfone

MECHANISM OF ACTION

1. Absorption It is completely absorbed after oral

administration

PHARMACOKINETICS

2. Distribution Approximately 70% bound to plasma

protein. The main metabolite, monoacetyl dapsone, is nearly 100% protein bound.

After oral administration the drug is mainly eliminated by kidney.20 percent is excreted unchanged while 80 percent as derivatives.

Only minor amount is excreted in faeces .

Bile: 10% of an oral dose was found in the bile

Breast-milk: Dapsone is excreted in breast milk

Elimination

Plasma concentration of Dapsone is reduced by Rafampicin.

Plasma concentration of both drugs may increase when Dapsone given with Trimethoprim.

This medication may decrease the effectiveness of combination-type birth control pills.

This can result in pregnancy.

DRUG INTERACTIONS:

Mycobacterium leprae infections (leprosy)./hansen’s disease

Linear Ig A Bullous disease Acne. Vasculitis Sweet syndrome Mycetoma

USES

Pyoderma GangrenosumApthous ulcerationGranuloma AnnularePneumocystis pneumonia.Dermatitis Herpetiformis.Toxoplasmosis - Prophylaxis

USES

DOSE DISEASE ADULT CHILDREN DAYS

Leprosy - Lepromatous

50-100 mg/day

6-10 mg/day 2-5 years

Leprosy - Tuberculoid

100 mg/day

NA 6 months

Dermatitis Herpetiformis

50-300 mg/day

NA Life long basis

Pneumocystis Pneumonia

100 mg/day

2 mg/kg/day 14-21 days

Pneumocystis Pneumonia Prophylaxis

100 mg/day

2 mg/kg/day Life long basis

Toxoplasmosis - Prophylaxis

100 mg/day

2 mg/kg/day Life long basis

Administered transdermally As a gel 5% topical acne medication available in 3-, 30-, and 60-gram tubes. In normal use, 0.5 grams should be

administered to the face per application twice a day.

TRANSDERMAL DOSE

Mild haemolytic anaemia (decreases with use of Vit C or Vit E ).Gastric intolerance-nausea & anorexiaMethaemoglobinaemia (treated with Cemitidine)

, headache, paresthesias, mental symptoms & drug fever

allergic rashes, fixed drug eruption, hypermelanosis, phototoxicity& rarely exfoliative dermatitis, steven Jhonsen syndrome.

Hepatitis & agranulocytosis

ADVERSE ACTION

Uncommonly weakness of the feet and hands muscles with dose greater then 100 mg/day It is tested by ability to walk on toes tip and to

test Hand grip.Leucopenia presents with fever ,sore throat ,skin

infections and other common infections.Bluish discoloration of lips and finger tips Dapsone reaction/sulfone syndrome

ADVERSE ACTION

Hypersensitivity more frequent in patients receiving

multiple-drug therapy.The reaction involves a rash and may

also include fever, jaundice, and eosinophilia.

Swollen lymph glands and internal organ failure (Liver , Lungs , Heart and Kidney).

In general, these symptoms will occur within the first six weeks of therapy or not at all, and may be treated by corticosteroid therapy.

Dapsone reaction

Allergic to sulphur containing antibiotics

G6PD deficiency Heart diseases Lung diseases Breast feeding Pregnancy Porphyria

Contraindications

FBC before the start of the therapy

Then at 1 weekThen once monthly

Monitoring