Purified horse serum diluted 1:100 (Solution) Instructions for Use

Marketing Authorization Holder

Microgen NPO, JSC (Russia)

ATC Code

V07AY (Other non-therapeutic adjuvants)

Dosage Form

Purified horse serum diluted 1:100

Solution for intradermal administration: 1 ml ampoules in a set with antitoxic serum

Dosage Form, Packaging, and Composition

Solution for intradermal administration

* by protein content

1 ml – ampoules (1) in a set with antitoxic serum (amp. 1 pc.) – cardboard packs.

Pharmacotherapeutic Group

MIBP-serum

Dosage Regimen

The purified horse serum diluted 1:100 is used exclusively for conducting an intradermal test for sensitivity to horse serum proteins. This test is a mandatory preliminary step before the administration of antitoxic serum to rule out anaphylactic reactions.

The dosage regimen involves the intradermal injection of 0.1 ml of the solution on the flexor surface of the forearm. A separate, sterile tuberculin syringe must be used for this procedure. The result of the test is assessed after 20 minutes.

A negative test is indicated by the formation of a papule at the injection site with a diameter of no more than 9 mm and slight redness of the skin surrounding it. A positive test is indicated by the formation of a papule with a diameter of 10 mm or more, often with pseudopodia, and significant hyperemia. A positive test result is an absolute contraindication for the administration of antitoxic serum by any method.

Adverse Reactions

The most common adverse reaction associated with the intradermal test is a local reaction at the injection site, which may include erythema, swelling, itching, and the formation of a papule. These local reactions are typically mild and self-limiting, resolving within a few hours.

In rare cases, particularly in individuals with a history of severe allergy, a systemic allergic reaction may occur. Signs of such a reaction can include generalized urticaria (hives), pruritus (itching), angioedema (swelling of the face, lips, tongue, or throat), bronchospasm (wheezing, difficulty breathing), tachycardia (rapid heart rate), hypotension (low blood pressure), and anaphylactic shock.

Medical personnel must be prepared to provide immediate emergency care, including the administration of epinephrine (adrenaline), antihistamines, and corticosteroids, in the event of a severe systemic reaction. The test should only be performed in a medical setting equipped to manage anaphylaxis.

Indications

The purified horse serum diluted 1:100 is indicated for a single, specific diagnostic purpose.

• It is used to perform an intradermal sensitivity test (test for individual sensitivity) to horse serum proteins prior to the administration of any antitoxic serum of equine origin.

This test is a critical safety measure to identify patients who may be at high risk for developing immediate hypersensitivity reactions, including life-threatening anaphylaxis, upon receiving the therapeutic antitoxic serum. It is an essential prerequisite for the safe use of serums for conditions such as diphtheria, tetanus, botulism, and gas gangrene.

Drug Interactions

The interpretation of the intradermal test can be significantly affected by the concomitant use of certain medications. Antihistamines (H1-receptor blockers) can suppress the cutaneous histamine response, potentially leading to a false-negative test result, which is extremely dangerous as it masks a true hypersensitivity.

It is recommended to discontinue antihistamines for a sufficient period (typically 3-5 half-lives of the specific drug) before performing the test, if clinically feasible. The use of systemic corticosteroids at high doses may also attenuate the skin test reaction, although this effect is less predictable than with antihistamines.

Topical corticosteroids applied directly to the test site on the forearm can also interfere with the result and should be avoided. Patients should inform their healthcare provider about all medications they are taking, including over-the-counter drugs and supplements, prior to the test.

Contraindications

The use of purified horse serum diluted 1:100 is contraindicated in the following situations:

• A known history of severe allergic reactions (anaphylaxis) to any component of the preparation or to horse serum in any form.
• A previous positive intradermal test with purified horse serum diluted 1:100 or a history of hypersensitivity reaction to equine-derived antitoxic sera.
• The presence of widespread skin diseases, such as severe eczema, psoriasis, or dermatitis, at the intended injection site (flexor surface of the forearm) that could interfere with the accurate reading and interpretation of the test result.

Absolute caution is required. Administration of the full therapeutic antitoxic serum is strictly contraindicated if the intradermal test yields a positive result. In such cases, the physician must consider alternative treatment strategies, which may include desensitization protocols performed under intensive medical supervision in a setting fully equipped for resuscitation.

Overdose

Overdose in the context of the intradermal test with purified horse serum diluted 1:100 is not a typical concept, as the administered volume is fixed at 0.1 ml for diagnostic purposes. However, the primary risk associated with the test itself is the provocation of a severe systemic allergic reaction, the management of which is similar to managing an overdose of an allergen.

In the event of a severe hypersensitivity reaction (e.g., anaphylaxis), immediate emergency measures must be initiated. The first-line treatment is the intramuscular injection of epinephrine (adrenaline) into the mid-outer thigh. This should be followed by securing the airway, administering supplemental oxygen, and establishing intravenous access.

Secondary treatments include the administration of parenteral antihistamines (e.g., diphenhydramine) and corticosteroids (e.g., hydrocortisone sodium succinate). Bronchodilators like salbutamol may be used if bronchospasm is present. Patients require close monitoring for several hours even after symptoms appear to have resolved due to the risk of a biphasic anaphylactic reaction.

Storage Conditions

Store at 2°C (36°F) to 25°C (77°F). Keep in original packaging, protected from light. Keep out of reach of children.

Dispensing Status

Rx Only

Important Safety Information

This information is for educational purposes only and does not replace professional medical advice. Always consult your doctor before use. Dosage and side effects may vary. Use only as prescribed.