Standardized Cat Hair

ALLERGY LABORATORIES, INC.
Oklahoma City, OK 73109

INSTRUCTION AND DOSAGE SCHEDULE FOR STANDARDIZED ALLERGENIC EXTRACTS 

CAT HAIR

The standardized (BAU/ml) extract in these vials is designed primarily for the physician equipped to prepare dilutions and mixtures as required. The sterile extract is prepared from the extractables of cat hair and cat wash and containes 50% (v/v) glycerine as a preservative. It is intended for subcutaneous injection.

The cat hair extract is assayed for potency using Radial immunodiffusion (1) against a reference extract distributed by the Center for Biologics Evaluation and Research, U.S. Food and Drug Administration. Potency based on Bioequivalent Allergy Units (BAU/ml) is printed on the label. Cat hair extract containing between 10-19.9 Fel d 1 U/ml are labeled 10,000 BAU/ml based on the quantitative skin testing (ID₅₀ EAL Method) (2). Standardized cat hair is compared to an FDA reference cat hair extract by IEF to establish identity.

Glycerinated extracts contain:

The allergic state is initiated by an immune response inducing B cells to produce IgE antibodies to specific allergens. IgE antibodies bind to surface receptors on mast cells and basophils. When antigens gain access to the immune system they react with the bound IgE. The reacting antigen to the surface bound IgE stimulates a number of chemical mediators to be released from the mast cells and basophils. These include histamine, Eosinophil Chemotactic Factor (ECF-A) and leukotrienes. These chemical mediators are pharmacologically active at low concentrations and are partially responsible for the biological manifestation of the allergic response. (3)

The mechanism by which immunotherapy achieves hyposensitization is not completely understood. There is an increase in 'blocking antibody" (IgG) titer and in some patients a decrease in specific IgE, a decrease in histamine release to specific allergen and an increase in suppressor cell population to specific allergen. These changes may occur only after prolonged therapy. (4)

Standardized Cat Hair Extracts are indicated for the diagnosis of patients with a history of allergy to cats and for treatment of patients with cat allergy. Diagnosis of allergic disease to cat hair is made through a combined medical history sufficiently complete to identify allergic symptoms to cat hair and identification of cat allergy by diagnostic skin testing.

Hyposensitization therapy is a treatment for patients exhibiting allergic reactions to cat. Immunotherapy is intended for patients whose symptoms cannot be satisfactorily controlled by avoidance of the offending allergen or by the use of symptomatic medications. (5)

There are no known absolute contraindications to hyposensitization therapy. See precautions section for pregnancy risks.

A patient should not be treated with allergens unless a history of symptoms and a positive skin test reaction have been demonstrated. Allergenic extracts should only be administered to patients that show symptoms of allergy or asthma. The physician must determine if the benefits outweigh the risks in using these products for treating these patients.

Patients who are taking non-selective beta blockers may be more reactive to allergens given for testing or treatment and may be unresponsive to the usual doses of epinephrine used to treat allergic reactions.

See WARNING at the beginning of the instruction sheet.

Extracts standardized using the Bioequivalent Allergy Unit (BAU/ml) may be more potent than extracts based on weight to volume, or PNU methods. Comparative skin tests can be performed to determine the relative potency before initial use of new extracts. DO NOT GIVE ALLERGY INJECTIONS INTRAVENOUSLY. Subcutaneous injections are recommended. Injections may produce large local reactions that may be painful to the patient. DO NOT GIVE FULL STRENGTH INJECTIONS UNTIL THE COMPARATIVE STRENGTH IS DETERMINED. After inserting the needle, but before injection extract, withdraw the plunger slightly. If blood appears in the syringe, re-insert the needle at another site. Careful selection of dose and injection should prevent most systemic reactions.

Local reactions:

Some swelling and redness at the site of injection is not unusual. Mild burning that occurs immediately after the injection is normal; this usually subsides in 10 to 20 seconds. If the swelling and redness persist for a period of 24 hours or longer this should be a sign to proceed with caution in increasing the dosage. With the next injection the dosage should remain the same or be decreased. Large local reactions may indicate that a systemic reaction could occur with the next injection if the dosage was increased. If a patient continues to have reactions at the maintenance dose, the patient is considered to have exceeded the maximum tolerated dosage.

Systemic Reactions:

Systemic reactions occur infrequently but must be looked for in all patients, especially highly sensitive patients. Anaphylactic shock and death are always possible, therefore, physicians must be prepared for the treatment of these reactions. Systemic reactions can also be characterized by one or more of the following symptoms: angioedema, tachycardia, conjunctivitis, cough, fainting, hypotension, pallor, rhinitis, urticaria, and wheezing.

Systemic reaction can be treated by the immediate application of a tourniquet above the site of injection and the administration of 0.3 to 0.5ml of 1:1000 Epinephrine - Hydrochloride subcutaneously or intramuscularly at the site of allergen injection. The dosage may be repeated two times at 15 minute intervals. Loosen the tourniquet at least every 10 minutes.

The pediatric dosage for 1:1000 Epinephrine-Hydrochloride is 0.05 to 0.1ml for infants to 2 years of age; 0.15ml, for children 2 to 6 years; and 0.2ml, for children 6 to 12 years.

Patients should always be observed for at least 30 minutes after any injection. Hypotension can be reversed by using vasopressor agents and volume expanders. Parenteral aminophylline and inhalation bronchodilators may be required for bronchospasm. Oxygen may also be needed. Maintenance of an open airway is critical if upper airway obstruction is present. Adrenal corticosteroids and intravenous antihistamine can be given after adequate epinephrine and circulatory support has been administered. Physicians must be familiar with these systemic reactions and have all the equipment and drugs necessary for proper treatment. (7)

DIAGNOSTIC SKIN TESTING:

Puncture tests performed on 10 highly sensitive patients with 10,000 BAU/ml Cat Hair Extract showed a mean sum of diameter wheal of 17.00mm ± 4.59 and a mean sum of diameter Erythema of 71.60 +14.01.

Intradermal skin test results in highly sensitive patients is shown below, using the same extract as used in the puncture test above.

These products are used to determine a patient's sensitivity to specific antigens and aid in the diagnosis and treatment of atopic diseases. After a thorough history a decision can be made as to which allergens will be appropriate to use for testing. The recommended procedure is to initially perform puncture tests, then follow with intradermal tests. See recommended dosage below.

The number of skin tests applied at one time will depend on the particular patient and their allergic history. These tests should be performed and observed in 15 to 20 minutes. Additional tests may be applied in sequence. Perform tests on the anterolateral aspect of the upper arm on an area that permits the effective application of a tourniquet proximal to the site of the test. The skin at the site of injection should be disinfected with rubbing alcohol before testing.

Puncture testing: Apply one drop (0.05ml) of extract to the skin. Pierce the drop of extract and skin using a sterile hypodermic needle or vaccinating needle. Maintain the needle perpendicular to the skin surface and rock the needle back and forth to produce a small hole without bleeding. Do not rotate or gouge the needle. Remove needle from skin and wipe excess extract from skin surface.

Scratch testing: Using a scarifier or needle, make a scratch 1/16 inch long on the epidermis penetrating the outer cornified area but being careful not to draw blood. Apply one drop (0.05ml) of allergen to the scratch.

Intradermal testing: use a separate sterile syringe (tuberculin type equipped with a 27 gauge by 3/8 inch needle with intradermal bevel) for each antigen. The tests are made by injecting 0.02ml of allergen into the epidermis. If the test has been performed properly, the solution should raise a bleb 2 to 3mm in diameter.  If the bleb does not appear, the injection was made too deeply.

A negative control consisting of the same solution that the extract was prepared in should be applied to one of the sites in the same manner as the tests being performed. For example, the negative intradermal control should contain 0.5% (v/v) glycerine, if a 100 BAU/ml concentration cat hair is used for intradermal testing. Histamine phosphate should be used as a positive control for evaluation of skin testing. Histamine phosphate is available from other manufacturers. See their directions for use, for recommended dosage and interpretation of results. 

A positive reaction usually develops in 15-20 minutes. The positive response is a wheal and flare reaction that is larger than the negative control and judged on the size of the reaction. Scratch or puncture tests may not elicit as large and well defined reaction as the intradermal. (5)

The following system is recommended (8):

The following are two methods of injection therapy:

1. Pre-seasonal in which treatment is begun three months before seasonal difficulty begins and brought to maintenance dose by injections four to seven days apart and discontinued after that season ends.
   
2. Perennial treatment is the recommended mode of therapy in which the patient is, by injection therapy, brought up to tolerated maintenance dose and remains at that dose until amelioration of allergic symptoms occurs. Injections may be given at intervals of 4 to 7 days.

Allergenic extracts must be diluted before use. Normally immunotherapy can be started with a 1 BAU/ml dilution. If a patient appears to be extremely sensitive, dilutions of the antigen can further be made before injections are started. The following are suggested procedures for making a proper dilution series. Recommended diluents contain 0.9% sodium chloride and 0.4% phenol as a preservative.

Perennial treatment may be started using the following dosage and dilution schedule. THIS SCHEDULE IS ONLY ILLUSTRATIVE AND HAS NOT BEEN SUBJECTED TO ADEQUATE OR WELL-CONTROLLED TRIALS TO DETERMINE EITHER ITS SAFETY OR EFFICACY.

Gradually increase the dose as outlined in the schedule. If you give a dose that causes a mild local reaction manifested by warmth or redness, repeat the same dose. If the reaction is severe or systemic (manifested as hives, asthma, or hay fever), drop back a dose in schedule and build again. If a severe local reaction or a systemic reaction is again encountered, this should be considered more than the maximum tolerance for this patient. The maintenance dose is the largest dose that relieves symptoms without producing local reactions. The size and interval of doses will vary and can be adjusted as necessary. The normal interval between doses is 4 to 7 days.

Bulk extract (stock concentrate) in 50% (v/v) glycerine containing 10,000 BAU/ml is supplied in 10ml, 30ml, and 50ml vials. Scratch testing in 50% (v/v) glycerine containing 10,000 BAU/ml is supplied in 2ml dropper vials. Intradermal testing (aqueous) containing 100 BAU/ml is supplied in 5ml vials.

These extracts should be stored at 2 to 8 degrees Celsius. Excessive heating (above room temperature) and repeated freeze-thawing should be avoided. The dating period (expiration date) is shown on the vial label. Once extracts are diluted the shelf life decreases. Extracts should be re-ordered when out of date. Please allow a minimum of three (3) weeks for delivery due to the holding period for sterility testing. 

      Revised 09/23/92

      L-049-00

1. Anderson, M.C., Baer, H.: Methodology for Assay of Cat Allergen 1 May 1986, In Methods of the Laboratory of Allergenic Products, Division of Bacterial Products, Food and Drug Administration.
   
2. Turkeltaub, P.C., Rastogi, S.C., Baer, H.: Assignment of Allergy Units to Reference Preparations using the ID₅₀ EAL Method, May 1986, In Methods of the Laboratory of Allergenic Products, Division of Bacterial Products, Food and Drug Administration.
   
3. Wasserman, S.I.: Biochemical mediators of allergic reactions. In Patterson, R. (ed): Allergic diseases: diagnosis and management, p. 86. Philadelphia, J.B. Lippincott Co. 1985.
   
4. Grammer, L.C.: Principle of immunologic management of allergic diseases due to extrinsic antigens. In Patterson, R. (ed): Allergic diseases: diagnosis and management, p. 358. Philadelphia, J.B. Lippincott Co. 1985.
   
5. Booth, B.H.: Diagnosis of Immediate Hypersensitivity. In Patterson, R. (ed): Allergic diseases: diagnosis and management, p. 102. Philadelphia, J.B. Lippincott Co. 1985.
   
6. Metzger, W.J., et al.: The safety of immunotherapy during pregnancy. J. Allergy Clin. Immunol., 64 (4): 268-272, 1978.
   
7. Patterson, R. et al.: Immunotherapy. In Middleton, E. Jr., Reed, C.E. and Ellis, E.F. (ed): Allergy; Principles and Practice, (Vol. 2) p. 1119. St. Louis, The C.V. Mosby Co. 1983.
   
8. Norman, P.S.: In vivo methods of study of allergy: Skin and Mucosal tests, techniques and interpretation. In Middleton, E. Jr., Reed, C.E. and Ellis, E.F. (ed): Allergy Principles and Practice, (Vol 1), p. 258. St. Louis, The C.V. Mosby Co. 1978.

ALLERGY LABORATORIES, INC. 
Oklahoma City, OK 73109 
U.S. License #103 
(405) 235-1451 •  800 654-3971

ALLERGENIC EXTRACT
STANDARDIZED CAT HAIR
Felis domesticus
10,000 BAU/mL
50 mL
RX ONLY

PRINCIPAL DISPLAY PANEL ALLERGENIC EXTRACT STANDARDIZED CAT HAIR Felis domesticus 10,000 BAU/mL 50 mL RX ONLY

ALLERGENIC EXTRACT
SCRATCH TESTING
STANDARIZED CAT HAIR
Felis domesticus
10,000 BAU/mL
Dose: 1 Drop
2 mL
RX ONLY

PRINCIPAL DISPLAY PANEL ALLERGENIC EXTRACT SCRATCH TESTING STANDARIZED CAT HAIR Felis domesticus 10,000 BAU/mL Dose: 1 Drop 2 mL RX ONLY