Data from FDA - Curated by EPG Health - Last updated 22 November 2019


INDICATIONS AND USAGE Studies have shown that skin tests with cat extract are useful in the diagnosis of cat allergy. As a rule, persons with cat allergy have positive skin reactions when tested with cat extract, and non-allergic individuals rarely react 7, 8, 9. However, the relationship between a positive skin test and the appearance of clinical symptoms after exposure to a cat is not absolute, i.e., some skin-test positive persons do not experience allergic symptoms after exposure 10. Failure to experience symptoms may be dose related, since it is known that cats vary significantly in the amount of Fel d 1 they produce 11. The efficacy of cat extract immunotherapy in the treatment of bronchial asthma has been shown in two studies 12, 13. A reduction in bronchial sensitivity was observed in five patients with cat allergy, whereas no reduction was observed in placebo treated, cat-allergic patients.

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Advisory information

CONTRAINDICATIONS Standardized Cat Hair Extract should not be used for immunotherapy in persons who do not have cat-related allergic symptoms and a positive skin test to the extract.
Special warnings and precautions
PRECAUTIONS GENERAL: Do not inject intravenously. After the needle is inserted subcutaneously, the plunger should be withdrawn slightly to check for the presence of blood in the syringe. If blood is observed, a new injection should be prepared and given at another site, observing the same precautions. The extract should be stored at 2°C-8°C. Dilutions of the 10,000 BAU/mL concentrate should be made with buffered saline containing human serum albumin for maximum stability. However, regardless of diluent type, diluted extract should be checked by skin test on a known cat-allergic individual if loss of potency is suspected. PREGNANCY CATEGORY C: Animal reproduction studies have not been conducted with Standardized Cat Hair Extract. It is also not known whether allergenic extract can cause fetal harm when administered to a pregnant woman or can affect reproduction capacity. Standardized Cat Hair Extract should be given to a pregnant woman only if clearly needed. PATIENT INSTRUCTIONS: Patients should be instructed to remain in the physician's office for at least 20 minutes after skin testing and after each treatment injection, and immediately notify the physician if symptoms of a generalized reaction or shock occur. CARCINOGENESIS, MUTAGENESIS, IMPAIRMENT OF FERTILITY: Long term studies have not been conducted with Standardized Cat Hair Extract to determine their potential for carcinogenesis, mutagenesis, and impairment of fertility. NURSING MOTHERS: Data are not available on the secretion of Standardized Cat Hair Extract in human milk and it is not known what effect this might have on the nursing infant. PEDIATRIC USE: The dose of Standardized Cat Hair Extract recommended for children is the same as that used for adults, except in the injection of large doses of extract for treatment. In this case, the amount of extract given to a child may be modified so that the discomfort of the injection is minimized. DRUG INTERACTION: The skin test response to Standardized Cat Hair Extract in sensitive persons may be suppressed by previous treatment with antihistamines and drugs with antihistamine activity. Treatment with beta-blocking drugs may make patients refractory to the usual dose of epinephrine, in the event epinephrine is required to control an adverse allergic reaction. Caution should be observed in the following circumstances: EXTREME SENSITIVITY TO CATS: Determined from previous anaphylaxis following skin testing or natural exposure. AUTOIMMUNE DISEASE: Individuals with autoimmune disease may be at risk, due to the possibility of routine immunizations exacerbating symptoms of the underlying disease. MYOCARDIAL INFARCTION: Patients who have experienced a recent myocardial infarction may not be able to tolerate immunotherapy. As in all of the above circumstances, the benefit to risk ratio must be carefully evaluated. Standardized Cat Hair Extract should be temporarily withheld from patients if any of the following conditions exist: (1) severe symptoms of rhinitis and/or asthma; (2) infection or flu accompanied by fever; and (3) exposure to excessive amounts of clinically relevant allergen prior to a scheduled injection.
Adverse reactions
ADVERSE REACTIONS Local Reactions From Skin Testing Large local reactions may result from skin tests with Standardized Cat Hair Extract. To help prevent this, a patient should be skin tested initially by the prick or scratch method. If a positive response is NOT observed, an intradermal skin test may be performed with a more dilute solution of the extract. Oral antihistamines and topical corticosteroids may be administered to relieve itching and swelling resulting from large skin test reactions. Local Reactions From Subcutaneous Injections The occurrence of a hive 5 to 15 minutes after the subcutaneous injection of extract is usually due to leakage of extract into the skin along the needle tract. Firm pressure (not rubbing) at the site of injection immediately after withdrawal of the needle will usually prevent this reaction. It does not require a reduction in dosage. However, a strong local reaction with erythema and edema which persists at the injection site for several hours indicates that too much extract has been given. Failure to note this response may result in a serious generalized reaction. Treatment should be altered as follows: Additional injections should not be given until all evidence of the reaction has disappeared. The next injection administered should be 50% of the last nonreacting dose or less, depending upon the size and severity of the local reaction. Subsequent injections should be continued at the reduced dosage unless the physician responsible for treatment believes that it is safe to increase the dose, and that possible clinical improvement would result from the administration of a larger dose of extract. Systemic Reactions Systemic reactions may range from a mild exacerbation of the patient's allergic symptoms to hives, anaphylactic shock, or even death from anaphylaxis. The reaction usually occurs 5 to 20 minutes after injection. As a rule, the more quickly a reaction develops, the more serious it is likely to become. Symptoms may include sneezing, coughing, itching, shortness of breath, abdominal cramps, vomiting, diarrhea, tachycardia, hypotension and respiratory failure in severe cases. The reaction is usually stopped by the subcutaneous injection of Epinephrine HCL 1:1,000 (See Overdosage below). The oral administration of antihistamines and the placement of a tourniquet proximal to the injection site are helpful adjuncts. In the event that additional measures are required, it may be necessary to treat the patient for BRONCHOSPASM with intravenous aminophylline, intravenous fluids and corticosteroids; for HYPOTENSION with vasopressors, volume repletion, isoproterenol and corticosteroids; for LARYNGEAL OBSTRUCTION with oxygen and tracheotomy and for CARDIAC ARREST with cardiopulmonary resuscitation and other appropriate measures.

Usage information

Dosing and administration
DOSAGE AND ADMINISTRATION Diagnosis: Concentrated extract (10,000 BAU/mL) may be used for scratch or prick-puncture testing. Puncture tests performed with a bifurcated needle in ten cat allergic persons showed a mean wheal diameter of 6.6 mm (S.D. 1.3) with a mean sum of erythema of 57.3 mm (S.D. 10.4). Intradermal tests with serial three-fold dilution of the 10,000 BAU/mL showed the following results: Serial 3-Fold Dilutions of 10,000 BSU/mL Extract Subject 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 1 X 2 X 3 X 4 X 5 X 6 X 7 X 8 X 9 X 10 X The mean three-fold dilution eliciting a response of 50 mm sum of erythema diameters was 11.120 (S.D. 2.38). The number of BAU/mL required to elicit this response was 0.05 (range 0.0003 to 9.24 BAU/mL). This concentration is approximately a 1:200,000 v/v dilution of the 10,000 BAU/mL extract. Extract for intradermal testing should be used as follows: Patients with a positive scratch or prick test to Standardized Cat Hair Extract. It is not advisable to perform an intradermal skin test in these patients. Patients with a negative scratch or prick test to Standardized Cat Hair Extract. Patients who do not react to a scratch or prick test with the 10,000 BAU/mL concentrate maybe tested intradermally with 0.05 mL of a 1:2,000 v/v dilution of the concentrate (5 BAU/mL). If the test is negative, a second test should be performed with 0.05 mL of a 1:200 v/v dilution of concentrate (50 BAU/mL). Patients tested only by the intradermal method with Standardized Cat Hair Extract. Patients suspected of being highly allergic to cats should be tested with 0.05 mL of a 1:200,000 v/v dilution (0.05 BAU/mL) of the concentrate. A negative test should be followed by repeat tests using 10 fold stronger concentrations until the maximum dose of 0.05 mL of a 1:200 v/v dilution (50 BAU/mL) is reached. Interpretation Of Skin Tests: The interpretation of skin tests should be based on the size of the erythema and wheal response to the allergen compared to a negative saline control. A suggested method of scoring skin tests is shown below. Measurements refer to the longest (single), diameter of erythema and wheal response. Scratch and Prick Test A negative test shows only a slight red area at the site of scarification or prick penetration. Positive tests are scored as follows: 1 + Erythema with a 5 mm wheal 2 + Erythema with a 5 -10 mm wheal 3 + Erythema with a 10 - 15 mm wheal 4 + Erythema with a wheal 15 mm (or larger) with pseudopodia Intradermal Test A negative test shows no change in the appearance and size of the 5mm wheal created by the I.D. injection of 0.05 mL of extract. Positive tests are scored as follows: 1 + Erythema 10 - 20 mm with a 5 -10 mm wheal 2 + Erythema 20 - 30 mm with a 5 -10 mm wheal 3 + Erythema 30 - 40 mm with a 10 - 15 mm wheal 4 + Erythema greater than 40 mm with a 15 mm wheal (or larger) with pseudopodia Immunotherapy Allergenic extract should be administered subcutaneously in the outer aspect of the upper arm using a sterile tuberculin syringe and needle. The skin should be cleaned with 70% alcohol and aseptic technique should be observed in removing the extract from the vial. Care must be taken to avoid injecting the extract into a blood vessel because of the potential hazard of anaphylaxis. Standardized Cat Hair Extract must be diluted before administration to new patients. As a precaution against overdose, a skin test with the intended starting dose should be done to help evaluate the patient's sensitivity to the product. If the skin response is larger than 5/15 mm (edema/erythema), the extract should be diluted before it is given subcutaneously. The doses shown in the Dosage Schedule may be followed unless the patient's skin test response and allergic history indicate that more dilute extract should be used. Little is known about the required accumulated dosage of Fel d 1 (and other allergens that may be present in cat extract) that is needed to relieve symptoms. However, studies with other allergenic substances have shown that high dose immunotherapy is most efficacious in the treatment of allergic rhinitis and asthma. The amount of cat extract that is tolerated during immunotherapy depends upon the sensitivity of the patient. In one study in which patients with cat asthma were treated for a period of one year, the accumulated dose of Fel d 1 varied from 3.6 to 115.8 (median 46.2) units 13. A burning sensation immediately following the injection of extract from the concentrate is due to the glycerol in the extract. It should not be interpreted as an adverse allergic response. Patients who have received allergenic extract for maintenance therapy SHOULD NOT be given the same dose from a fresh vial of extract. IT IS ADVISABLE TO REDUCE THE DOSAGE OF FRESH EXTRACT TO ONE-FOURTH THE AMOUNT GIVEN FROM A PREVIOUS LOT. Dosage Schedule for Standardized Cat Hair Extract (The safety and efficacy of this schedule has not been determined by well-controlled clinical trials.) [BAU = Bioequivalent Allergy Units per mL] Vial #1 0.05 BAU Vial #2 0.5 BAU Vial #3 5 BAU Vial #4 50 BAU Vial #5 500 BAU Vial #6 5,000 BAU frequency twice weekly No. mL mL mL mL mL mL 1 0.05 0.05 0.05 0.05 0.05 0.05 2 0.1 0.1 0.1 0.1 0.1 0.1 3 0.2 0.2 0.2 0.2 0.2 0.2 4 0.3 0.3 0.3 0.3 0.3 0.3 5 0.4 0.4 0.4 0.4 0.4 0.4 v/v dilutions of concentrate containing 10,000 BAU per mL required to make the above concentrations. BAU per mL v/v Dilutions of Concentrate 0.05 1:200,000 0.5 1:20,000 5.0 1:2,000 50.0 1:200 500.0 1:20 5,000.0 1:2

More information

Category Value
Authorisation number BLA103473
Agency product number 1564HD0N96
Orphan designation No
Product NDC 49643-705
Date Last Revised 26-09-2019
RXCUI 851948
Storage and handling STORAGE AND HANDLING Extract should be stored at 2°C to 8°C since higher temperatures may adversely affect stability. Do not freeze.
Marketing authorisation holder Allermed Laboratories, Inc.
Warnings WARNINGS This allergenic product is intended for use by physicians who are experienced in the administration of allergenic extracts and the emergency care of anaphylaxis, or for use under the guidance of an allergy specialist. Standardized Cat Hair Extract is not directly interchangeable with Standardized Cat Pelt Extract or Cat Extracts labeled in Allergy Units (AU/mL) The initial dose must be based on skin testing as described in the dosage and administration section of this insert. Patients being switched from other types of cat extracts to Standardized Cat Hair Extract should be started as though they were coming under treatment for the first time Patients should be instructed to recognize adverse reaction symptoms and cautioned to contact the physicians office if reaction symptoms occur. As with all allergenic extracts, severe systemic reactions may occur. In certain individuals these reactions may result in death. Patients should be observed for at least 20 minutes following treatment and emergency measures as well as personnel trained in their use should be immediately available in the event of a life threatening reaction. This product should not be injected intravenously (see Dosage and Administration). Refer also to the warnings, precautions, adverse reactions and overdosage sections below. Serious adverse reactions to this product should be reported to MEDWATCH, Food and Drug Administration, 5600 Fishers Lane, MD 20852-9787. Telephone 1-800-822-7967 or