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Tetanus antitoxin is prepared by hyperimmunising
horses with tetanus toxin. Blood plasma obtained from the
hyperimmunised horses which is rich in antibodies to tetanus
toxin, is enzyme refined purified and concentrated. The
antitoxin has the specific power of neutralising the toxin
secreted by Clostridium tetani, the causative organism of
tetanus.
Use
in prophylaxis : A dose of 1500 international units
of tetanus antitoxin should be injected subcutaneously or
intramuscularely, after testing for serum sensitivity (see
below for reactions to horse serum). It should be injected
as soon as possible after tetanus prone injury, such as
wounds contaminated with soil, dirt etc. Adequate surgical
treatment of wounds with the use of suitable antibiotics
should be carried out in addition to the prophylactic injection
of antitoxin, if the patient is sensitive to serum or has
been actively immunised previously with tetanus vaccine
(adsorbed) the patient shuld receive the dose of tetanus
vaccine(adsorbed) only and not tetanus antitoxin. The use
of antitoxin gives protection for 1 to 3 weeks only. While
tetanus vaccine gives long time immunity and is cheaper
and practically free from reactions. It is also adviced
that simultanously with the administration of the prophylactic
dose of tetanus antitoxin active immunization should be
started. This is done by injecting at the same time in another
arm, 0.5ml of adsorbed tetanus vaccine (Tet./Vac./P.T.A.P.)
since adsorbed tetanus vaccine is able to actively immunize
against tetanus even in the presence of tetanus antitoxin
(B.J.Vakil et al Ind. J.Med. Research, 1968 Vol.56 pp 1188-1201).
A second dose of 0.5ml adsorbed tetanus vaccine only is
to be injected between 1 to 2 months after the first dose
of vaccine and a third dose 6 to 12 months after the second
dose to produce adequate long term protection.
Use
in treatment of tetanus:
It is recommended that a dose of 10000 to 20000
I.U. of tetanus antitoxin should be injected intramuscularly
soon after admission of patient with symptoms of tetanus
such as lockjaw, muscular spasms, etc. after taking precautions
against possible serum reaction. The dose of 10000 to 20000
I.U. is now considered adequate (J.C.Patel et al. proceeding
of the first international conference of tetanus p 346,
B.J.Vakil et al ibid, p.337 the study group of tetanus,
Bombay 1965). In addition, symptomatic treatment consisting
of antibiotics, sedatives, anticonvulsants and muscle relaxants
may be given. The patient should be actively immunized with
adsorbed tetanus vaccine (Tel/Vac/PTap), at the time of
discharge and advised to return after 1 or 2 months for
a second dose of the adsorbed tetanus and 6 to 12 months
later for the third dose.
Reaction
due to horse serum:
Injection of tetanus antitoxin in horse serum sensitive
subjects can produce immediate reaction of acute anaphylaxis
which could sometimes be fatal unless immediately countered
by injecting 1ml of 1:1000 adrenaline intramuscularely.
Every care should be taken to prevent these reactions. Before
injection of tetanus antitoxin it is necessary to enquire
from the patient
(1) whether he has had injections of any serum previously
(2) whether there is personal or family history of allergy,
i.e. asthma, eczema or drugs allergy. The sensitivity of
the patient for serum is tested by injecting subcutaneously
0.1ml of tetanus antitoxin diluted 1:10. The patient should
be observed for 30 mins. for local and general reaction.
If the test dose show either local reaction such as pallor,
sweating, nausea, vomitting, urticaria or fall of blood
pressure, these should be countered immediately by injection
of 1ml of 1:1000 adrenaline (which should be always kept
handy, before injecting the main dose of tetanus antitoxin).
Half the dose of adrenaline may be repeated 15 min. later
if necessary.
In
allergic indivisuals, the tetanus 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 antiserum.
Administration of hydrocortisone or adrenaline may be repeated
if necessary.
In
some cases symptoms such asitching, urticarial rash, pains
in joints and muscule, fever, enlargement of lymph glands,
appear about 7-12 after injection of serum. These should
be treated with antihistamines and corticosteriods. Usually
these sumptoms of serum sickness last a few days and patients
recover without any complication.
Storage
The antotoxin should be stored at a temp. of 2oc
to 8oc. It should not be allowed to freeze.
Packing
Tetanus Antisera :
1. Prophylactic - Tetanus antitoxin 1500 I.U. in 1 ml
2. Therapeutic
a] Tetanus antitoxin 10,000 I.U. in 3.4ml
b] Tetanus antitoxin 20,000 I.U. in 5ml.
Tetanus
vaccine
1. Tetanus vaccine (adsorbed) (Tet/Vac/PTAP) in 0.5ml and
5ml.
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