Leprosy
Mailing List – November 11th, 2007
Ref.: Dapsone
From: Salafia A.,
Mumbai, India
Dear
Salvatore,
This
has reference to the ‘discussion going on about Dapsone and its side
effects.
I
use Dapsone extensively and so far I have used in more than 20
thousand leprosy patients (in Bombay, Bangalore, Surat) and another 20
thousand Vitiligo patients; besides these large numbers, Dapsone has
been used by me in cases of Nodular Vasculitis, Bullous Pemphigoid,
Psoriasis of Von Zambush type, Dermatitis Herpetiformis, Sneddon
disease and Acne Vulgaris. There
are a few other clinical uses of Dapsone that are worth noting:
Pityriasis Rubra Pilaris, Herpes Gestationis, Grover’s disease,
Cicatricial Pemphigoid and Epidermolysis Bullosa Acquisita, Linear IgA
dermatitis.
In
all these years I have come across with 3 cases of Haemolytic anaemia;
an elderly lady with Nodular Vasculitis, another elderly lady with
leprosy, and a young lady whose diagnosis I do not recall. Further I had 2 cases of
Methaemoglobinimia; one a young child – belonging to the Muslim
Bohra community – suffering from Vitiligo and a Parsee lady. Now, in India it is a
known fact that Parsees are generally deficient in G-6PD and some
Bohra too. Methaemoglobinimia
is common in the area of the Caribbean and the Mediterranean. I have given Dapsone 25 mgs a
day to 12 Parsees, all proved to be G-6 PD deficient, and yet, there
were not clinical signs of Methaemoglobinimia; the reason being that
the side effects of Dapsone are dose-related: any dose above 1.5
mgs/Kg/wt./day can cause side effects.
Let
me elaborate a little more: I
have done an in-depth study on Dapsone: just because I use it so
extensively, I wanted to be sure of the problems I could face. The
main points:
1.
Methaemoglobin
(MEG): a normal subject produces circa 3% of MEG along with the normal
Haemoglobin (HMG).
2.
Clinically
what really matters is the percentage of MEG against the total HGM:
for example, if a patient has a total of HGM of 10 g/dl, out of which
10% is MEG, than the total functional HGM will be about 9 g/dl and the
patient may have clinical signs of anaemia, pallor, ashen face and
complaint of tiredness. If,
however, a patient has a total HGM of 15/g/dl, out of which 10% is
MEG, then the total functional EGM will be about 13.5 g/dl and the
patient will have no clinical signs. Incidentally
in all cases of Leprosy and Vitiligo I get Iron supplements.
3.
Some
authors claim that Vitamin E, in dosages of 800 mgs. OD, and
Cimetidine, in dosages of 400 mgs. TID, can prevent the formation of
MEG.
4.
Methylene
Blue can reduce the level of Methaemoglobinimia, but it is not so
effective when Methaemoglobinimia is due to G-6 PD deficiency.
5.
Finally,
Methaemoglobinimia can occur in normal individuals.
All
this leads us to say that Dapsone is an extremely safe drug (and very
cheap); however if a patient belongs to the communities mentioned
above, he/she should be tested for G-6 PD, and finally, in the dosages
used in Leprosy (I give 1 mg./kg/wt. and in Vitiligo ˝ mg), Dapsone
hardly gives any side effects.
Dr.
A. Salafia
Chief
of Reconstructive Surgery and senior most Dermatologist, Vimala
Dermatological Centre, Mumbai, India
