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POLYVALENT SNAKEBITE ANTISERUM

THE SOUTH AFRICAN INSTITUTE FOR MEDICAL RESEARCH
SERUM AND VACCINE DEPARTMENT, RIETFONTEIN.
Modderfontein Road, Edenvale, Transvaal · P O Box 1038, Johannesburg, 2000 · Telegrams “Bacteria”

PROPRIETARY NAME
(and dosage form):

POLYVALENT SNAKEBITE ANTISERUM

DESCRIPTIVE NAME:
POLYVALENT SNAKE BITE ANTISERUM (ANTIVENOM) (REFINED EQUINE SERUM GLOBULINS).

REGISTRATION NO.:
T517 (Act 101 1965)

PHARMACOLOGICAL CLASSIFICATION:
A30.2 ANTIBODIES

SCHEDULING STATUS:
S1

COMPOSITION:
Pepsin-refined immunoglobulins, prepared from the serum of horses that have been hyper-immunised with snake venoms. The venoms of the following snakes are used as antigens in the preparation of Polyvalent Antivenom:–Bitis arietans (puff adder), B. gabonica (Gaboon adder), Hemachatus haemachatus (rinkhals), Dendroaspis angusticeps (green mamba), D. jamesoni (Jameson's mamba), O. polylepis (black mamba) Naja nivea (Cape cobra), N. melanoleuca (forest cobra), N. haje (Egyptian cobra), N. mossambica (black-necked cobra). Contains 0,3% Cresol as preservative.

It conforms to the potency requirements laid down in the South African Therapeutic Substances Regulations.

IDENTIFICATION:
A light yellowish to light brown clear liquid.

PHARMACOLOGICAL ACTION:
Neutralises the venom of specific snakes.

INDICATIONS:
For the treatment of snake bite as follows:-
Polyvalent Antivenom (Bitis, Dendroaspis, Hemachatus, Naja).
This serum is effective against the venoms of the rinkhals, the mambas and all the cobras and vipers likely to cause serious accidents in Southern and Central Africa. Serum treatment is usually not required for bites by the night adders (Causus).
The serum is ineffective, AND SHOULD NOT BE USED in the treatment of bites caused by the berg adder (Bitis atropos), the horned adders (Bitis cornuta, B. caudalis), the burrowing adder (Atractaspis) and back-fanged snakes (boomslang, vine snake).

In the laboratory this serum neutralizes the venoms of some “foreign”snakes, such asPseudohaje goldii, Walterinnesia aegyptia, Ophiophagus hannah and Asian Naja species.

CONTRA INDICATIONS:
Significant allergic disease, or a history of an adverse reaction to the injection of serum.

DOSAGE AND DIRECTIONS FOR USE:
Everyone bitten by a snake should be referred to a hospital or doctor whether he is treated in the field or not. Treatment with serum should take place under medical supervision whenever possible, but the following table has been formulated on the assumption that treatment before hospitalisation will be carried out by a lay person. If the patient himself, or one of his companions, is medically qualified the scheme should be modified, e.g. intravenous injection would be recommended.

N.B.:–BEFORE INJECTING, CARRY OUT THE INITIAL FIRST AID PROCEDURES AS DETAILED BELOW:–

THE PRESSURE BANDAGE
In all cases of snake bite a broad bandage (preferably a crêpe bandage) should be applied as soon as possible around the limb, covering the bitten area and as much of the limb as possible. This may be supplemented with other material, e.g. a strip torn off a shirt. It should be applied as tightly as one would bind a sprained ankle. The limb must be kept as still as possible by splinting with wood, cardboard, rolled newspaper, or any available rigid material. If the use of a tourniquet is thought necessary, the pressure bandage and splint should still be applied.

TOURNIQUET:
The use of a tourniquet is no longer recommended, except under special circumstances. It should never be used in viper (adder) bites, but it will delay general poisoning by the venoms of the more dangerous elapid snakes (e.g. black mamba) if the nearest medical assistance is several hours away. The tourniquet (belt, strap or rubber bandage) should be placed as soon as possible on the upper arm or above the knee, depending on the site of the bite. It should be applied firmly enough to occlude the pulse at the wrist or ankle, but should not be left on for more than about one and half hours, and should be released for a few seconds every 15 to 30 minutes. The momentary release of the tourniquet may allow more venom to enter the general circulation, which may aggravate the patient's symptoms. It should be discarded altogether as soon as an adequate dose of antivenom has been injected intravenously. It should not be applied when more than an hour has elapsed since the bite, if there are no signs of general poisoning.

SNAKE VENOMS:
These can be classified as follows:–

1.	Haemotoxic (boomslang, vine snake): Causing continued bleeding due to a coagulation defect.
2.	Cytotoxic (adders): Causing tissue destruction around the site of the bite with localised bleeding.
3.	Neurotoxic (cobras, mambas): Causing paralysis of the muscles of swallowing and respiration.

GENERAL TREATMENT
Keep the patient quiet and comfortably warm and avoid unnecessary movement. Small amounts of water, tea or coffee may be given and alcohol in moderation if the patient has no difficulty with breathing or swallowing. Artificial respiration my become necessary if bitten by an elapid snake. All patients should be taken to a hospital or doctor as quickly as possible whether they have received serum or not. Incisions are not recommended. Suction should be applied to the fang marks. A mechanical suction device is enclosed in each Snakebite Outfit.

A patient bitten by an unidentified viper can be dismissed from hospital if signs of poisoning have not appeared after a few hours. Patients bitten by an elapid snake (cobra, rinkhals, mamba) or an unidentified snake should be observed for 24 hours. A patient suffering from a suspected or known boomslang bite should be kept under observation for five days.

SERUM TREATMENT
When it can be done without risk of pressure necrosis, immediate infiltration of the bitten site with serum may be of value in adder bites, but any injection of serum carries a risk and should as far as possible be left to a doctor, preferably in a hospital, who would be able to inject the serum by the most effective route, i.e. directly into the blood stream. It may, however, be necessary for a lay person to inject serum in which case the procedure would be as follows:

The tip of the ampoule should be snapped off (see instruction enclosed with the ampoule) and the contents drawn into a sterile syringe. The skin should be sterilized with the swab supplied in the Snakebite Outfit or with any other suitable disinfectant, but time should not be wasted looking for one.

The needle of the syringe is inserted either under the skin or into a muscle and the contents of one ampoule slowly expelled. The needle is then withdrawn, the syringe re-filled and the contents given in the same way at another site. When delay has occurred, when the patient is in a critical state and particularly when the snake is a cobra or a mamba, the serum should be injected intravenously but this route should be used only by trained medical personnel. The initial dose should be large, at least the contents of two ampoules, but the condition of the patient may demand the injection of up to four or five times as much. When given intravenously, the serum should be at room temperature, and the injection given very slowly, with the patient recumbent during the injection, and for at least one hour afterwards.

The dose of serum required depends on the amount of venom injected by the snake, not on the size or mass of the victim, and should not be reduced in the case of children.

SIDE EFFECTS AND SPECIAL PRECAUTIONS:
The injection of even highly purified serum carries a risk of untoward reactions. The commonest is serum sickness which may occur about ten days after the injection but sometimes sooner. It is characterized by itching rashes and sometimes a rise in temperature and joint pains. Proper treatment (antihistaminics, steroids) should alleviate the symptoms.

A rare but far more serious complication is an acute serum reaction (anaphylaxis) with a sudden drop in blood pressure and collapse within a few minutes. The risk of this type of reaction in a healthy person is very slight but those with an allergic disposition, in particular a history of asthma or infantile eczema, should not receive serum unless it is absolutely necessary and then only with the greatest caution. Treatment for this condition includes the injection of adrenalin.

When serum treatment, although not imminently urgent, may become necessary, a trial dose of 0,1 mL of serum diluted 1:10 in sterile saline or water could be injected under the skin. If there is no untoward reaction within half an hour, 0,2 mL of undiluted serum could be given in the same way, to be followed, if necessary, by the full dose if no reaction occurs to this trial dose.

Where possible, whenever serum is to be injected, the patient should be kept under observation for at least 30 minutes after the injection, and adrenalin and corticosteroid kept in readiness for emergency use.

KNOWN SYMPTOMS OF OVERDOSAGE AND PARTICULARS OF TREATMENT:
None. Treat symptomatically.

PRESENTATION:

1.	10 mL Ampoules packed singly.
2.	A Snakebite Outfit containing two 10 mL ampoules, pressure bandage, tourniquet, syringe and needle, suction syringe, antiseptic swab.

STORAGE DIRECTIONS:
Store at 2°C to 10°C. Freezing of the serum will not affect its potency, but may cause the ampoule to crack. Stored in a cool place the serum will retain its potency for years in excess of the stated expiry date. When not under refrigeration but at a reasonably low temperature, loss of potency is slight, and serum may be used if it has remained clear. Exposure to higher temperatures will cause a marked loss in potency, accompanied by cloudiness which makes the serum unsuitable for use.
When going on an excursion, pre-cool the serum before setting out, keep it cool during the excursion and return it to the cold box afterwards.

NAME OF APPLICANT:
The South African Institute for Medical Research, Hospital Street, P.O. Box 1038, Johannesburg, 2000.

OTHER ANTI-SNAKEBITE SERA ISSUED BY THE INSTITUTE:
Boomslang (tree snake) Antivenom:
This is effective against the venom of the boomslang (Dispholidus typus), but not against the venom of the vine-, bird-, or twig-snake (Thelotornis). It is in short supply but is issued on request to any hospital treating a patient bitten by a boomslang. Boomslang antiserum is supplied as a freeze-dried powder.

        146-989
SAIMR P852503 REVISED SEPTEMBER 1989
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