DIPHTHERIA ANTITOXIN B.P.
(Equine Origin)


 
 

DESCRIPTION
Diphtheria antitoxin is a sterile, nonpyrogenic solution of refined and concentrated protein ( mainly immunoglobulins ) containing antitoxic antibodies. The solution is prepared from the plasma or serum of healthy equines hyperimmunized against diphtheria toxin. Diphtheria antitoxin injection contains 0.25% phenol as preservative.
Diphtheria antitoxin occurs as a transparent or slightly opalescent liquid and has slight odour because of the preservative.


USES AND ADMINISTRATION
Diphtheria Antitoxin is used in the treatment of diphtheria and rarely as prophylactic of diphtheria in asymptomatic, non-immunised
individuals who have been exposed to diphtheria. Diphtheria antitoxin neutralizes the toxin produced by Corynebacterium diphtheriae locally at the site of infection and in the circulation.

Diphtheria antitoxin is used for passive immunization in suspected cases of diphtheria and should be given without waiting for bacteriological confirmation of the infection. An antibacterial agent such as erythromycin or benzylpenicillin is usually given concomitantly. Diphtheria Antitoxin is generally not used for the prophylaxis of diphtheria because of the risk of provoking a hypersensitivity reaction. Contacts of a diphtheria case should be promptly investigated, given a prophylactic course of erythromycin and active immunization with a suitable diphtheria containing vaccine as appropriate and keep under observation.

A test dose of diphtheria antitoxin should always be given to eliminate hypersensitivity. For the treatment of diphtheria of mild or moderate severity, doses of 10,000 to 30,000 units of diphtheria antitoxin may be given intramuscularly, doses of 40,000 to 100,000 units may be given in severe cases. Higher doses have been used in some countries. Doses of more than 40,000 units should be given intravenously about 0.5 to 2 hours after the initial portion of the dose has been given intramuscularly.


TREATMENT OF DIPHTHERIA
In the treatment of diphtheria, diphtheria antitoxin should be administered as soon as the clinical evidence of the disease appears; administration of the antitoxin should not await bacteriologic confirmation of the diagnosis since the condition of the patient with diphtheria can deteriorate rapidly.
 

PROPHYLAXIS OF DIPHTHERIA
Diphtheria antitoxin is rarely used for the prophylaxis of diphtheria. Chemoprophylaxis with an anti-infective agent ( i.e. a 7 to 10 day course of oral erythromycin or a single IM dose of penicillin G benzathine) and active immunization with a diphtheria toxoid preparation is the recommended therapy for prophylaxis of respiratory or cutaneous diphtheria in asymptomatic, non-immunised household or intimate contacts.

Diphtheria antitoxin is administered by IM injection or slow IV infusion. Sensitivity testing must be performed prior to the administration of diphtheria antitoxin ( See Sensitivity Testing and Desensitization ) Diphtheria antitoxin and diphtheria toxoid should not be given in the same syringe nor injected at the same site since neutralization of the vaccine may occur.
Specimens for bacteriologic culture should be obtained before and after treatment or prophylaxis of diphtheria. For the treatment of
diphtheria, diphtheria antitoxin should be administered by IM injection or IV infusion as soon as clinical evidence of the disease appears; administration of the antitoxin should not await bacteriologic confirmation of the diagnosis. In patients with severe infections, the antitoxin preferably should be administered by slow IV infusion to neutralise the toxin as rapidly as possible.

For IV infusion, the appropriate dose of diphtheria antitoxin should be diluted with an appropriate volume of 0.9 % sodium chloride injection or 5 % dextrose injection to provide a 1 : 20 dilution of the antitoxin.
The solution may then be infused directly into a vein at a rate not exceeding 1 ml/minute.
 

ADVERSE EFFECTS AND PRECAUTIONS
Reactions are liable to occur after the injection of any serum of animal origin. Anaphylaxis ( type I hypersensitivity reaction ) may occur with hypotension, dyspnoea, urticaria and shock. A history of evidence of sensitivity of equine serum, asthma or other allergies should be obtained prior to administration of diphtheira antitoxin, however, sensitivity testing should be performed in all individuals regardless of allergic history or a history of prior administration of preparation containing equine serum (see Dosage and Administration : Sensitivity Testing and Desensitization). Diphtheria antitoxin should be used with extreme caution in individuals with a history of allergic disorders and/or who have exhibited previously sensitivity to equine serum.
Epinephrine and other supportive measures should be available for immediate management of an anaphylactic reaction if it occurs.


SENSITIVITY TESTING AND DESENSITIZATION
Prior to the use of diphtheria antitoxin, an intradermal or scratch skin test and a conjunctival test for serum sensitivity should be performed. Whenever possible, both the conjunctival test and the intradermal or scratch skin test should be performed. The intradermal skin test procedure consists of intradermal injection of 0.1 ml of a 1:100 dilution of diphtheria antitoxin in 0.9% sodium chloride injection : the intradermal skin test is read after 20 minutes. When the patient has a history of allergy, 0.05 ml of a 1:1000 dilution should be used for preliminary intradermal skin testing. A control test using 0.9% sodium chloride injection facilitates interpretation of the results. A positive intradermal skin test reaction consists of an urticaria wheal, with or without pseudopods, surrounded by a zone of erythema. Alternatively, a scratch skin test for sensitivity may be performed. The scratch skin test procedure consists of placing 1 drop of a 1:100 dilution of diphtheria antitoxin on the skin and then making a 0.64-cm (1/4-inch) scratch through the drop; the scratch skin test is read after 20 minutes. A control test using 0.9% sodium chloride injection facilitates interpretation. A positive scratch skin test reaction consists of an urticaria wheal, with or without pseudopods, surrounded by a zone of erythema. The conjunctival test procedure consists of placing 1 drop of a 1:10 dilution of diphtheria antitoxin into the lower conjunctival sac of one eye; the test is read after 15 minutes. A control test using 0.9% sodium chloride injection that is placed on the other eye facilitates interpretation of the results. A positive conjunctival test reaction consists of itching, burning redness and lacrimation: these signs and symptoms can be relieved by placing 1 drop of an ophthalmic solution of epinephrine on the affected eye. A negative intradermal, scratch or conjunctival sensitivity test is usually considered reliable but does not completely rule out systemic sensitivity. When the skin or conjunctival test is positive or a doubtful reaction occurs, the risk of administering diphtheria antitoxin should be weighed against the risk of withholding it, If diphtheria antitoxin must be used, desensitization should be performed.
The procedure for desensitization consists of subcutaneous injection of the following doses of diphtheria antitoxin at 15 minutes intervals; 0.5 ml of a 1:20 dilution, 0.1 ml of a 1:10 dilution, 0.3ml of a 1:10 dilution, 0.1 ml of undiluted diphtheria antitoxin, and 0.2 ml of undiluted diphtheria antitoxin; after 15 minutes, 0.5ml of undiluted diphtheria antitoxin is administered IM. If an immediate sensitivity reaction occurs at any time during the desensitization procedure, a tourniquet should be applied proximal to the sites of injection and epinephrine administered proximal to the tourniquet. After 1 hour, the procedure may be continued by injecting the last dose of antitoxin that did not produce a reaction. If no reaction occurs after 0.5 ml of undiluted diphtheria antitoxin has been administered, the remaining usual dose may be administered IM or IV. (See Dosage and Administration : Dosage.) An allergist, immunologist, and / or other experts should be consulted for advice on treatment of patients who develop signs or symptoms of impending anaphylaxis despite desensitization.


STORAGE AND STABILITY
Diphtheria antitoxin injection should be stored in the dark between 2-8C.
DO NOT FREEZE.
 

PRESENTATION
1000 IU ( 1ml ) x 50 ampoules box
2000 IU ( 2 ml ) x 50 vials box
10,000 IU ( 10ml ) x 25 vials box

 

 

 

 

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