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Diphtheria
Antitoxin is prepared by hyperimmunizing horses with diphtheria
toxin, blood plasma obtained from the hyperimmunised horses
which is rich in antibodies to diphtheria toxin is enzyme
refined, purified and concentrated. The antitoxin has the
specific power of neutralising the toxin secreted by Corynebacterium
diphtherea the causative organism of diphtherea.
Use
in prophylaxis :-
The
use diphtheria antitoxin is not recommended for prophylaxis
as its protective effect is of short duration (1 to 2 weeks
only) and furthermore, it may cause sensitization to horse
sera. Instead the contacts of diphtheria patients should
receive a dose (0.5ml) of adsorbed diphtheria vaccine (diphtheria
vaccine adsorbed PTAP) or adsorbed diphtheria-tetanus vaccine,
(DT vaccine adsorbed PTAP, which protects against both
diphtheria and tetanus) and followed after 1 to 2 months
with a second dose. Prophylaxis with diphtheria vaccine
gives protection for many years and is practically free
from reaction.
Use
in treatment :-
A
dose of 10,000 to 30,000 IU of diphtheria antitoxin may be
injected intramuscularly in mild to moderately severe cases
of diphtheria and up to a max. of 1,00,000 IU in severe cases
after testing for serum sensitivity (see below for reactions
to horse serum). In addition antibiotics and corticosteroids
may be administered. It is advised that after recovery from
diphtheria, the patients should be actively immunized for
long term protection by use of two doses at an interval
of 1 to 2 months with adsorbed diphtheria vaccine or with
adsorbed diphtheria-tetanus vaccine.
Reaction
to Horse Serum :-
Injection
of diphtheria antitoxin in horse-serum-sensitive individual
can produce immediate reaction of acute anaphylaxis which
could sometimes be fatal unless immediately countered by
injecting 1ml of 1:1000 adrenaline intramuscularly. Every
care should be taken to prevent this reaction. Before injection
of diphtheria antitoxin it is necessary to enquire from
the patient
1) Whether he/she has had injections of any serum before
2) Whether there is personal or family history of allergy
i.e. asthma, eczema or drug allergy. The sensitivity of
the patient to serum is tested by injecting subcutaneously
0.1ml of diphtheria antitoxin diluted 1:10 and the patient
is observed for 30 min. for local and general reactions.
If the test dose shows either local reaction such as wheal
and flare or general anaphylactic reaction such as palor,
sweating, nausea, vomiting urticaria or fall of blood pressure,
these should be treated with 1ml of 1:1000 adrenaline (which
should always be kept handy) before injecting the main dose
of diphtheria antitoxin. Half the dose of adrenaline may
be repeated 15 min. later if necessary.
In
allergic individuals, the diphtheria antitoxin is to be
injected 15 to 30 mins. after administration of antihistamines
such as injectable Antistine (100mg) and Injectable Hydrocortisone
(100mg) intramuscularly. One ml of Adrenaline (1:1000) may
be injected intramuscularly at the same time as the antiserums.
Administration of hydrocortisone or adrenaline may be repeated
if necessary.
In
some cases symptoms such as itching urticarial rash, pains
in joints and muscles, fever, enlargement of lymph glands
appear 7-12 days after the injection of diphtheria antitoxin.
These should be treated with antihistamines and corticosteroids.
Usually these symptoms of serum sickness last a few days
and the patients recover without any complications.
Packing
:
Diphtheria antitoxin
1.) 10,000 IU in 10ml vials
2.) 10,000 IU in 5ml vials
Diphtheria
Vaccine
1.) 0.5ml ampoules
2.) 5.0m vials
Diphtheria
Tetanus Vaccine 1.) 0.5ml ampoles
2.) 5.0ml vials
Storage
:
The diphtheria antitoxin should be stored at a temp. of
2oCto 8oC. It should not be allowed
to freeze.
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