Alfalfa Solution
FDA Label NDC 22840-5503

Warning and Precautions, Anaphylaxis Following False Negative Food Allergen Skin Test Results (5.3) 01/2023

These highlights do not include all the information needed to use Non-Standardized Allergenic Extracts (Pollens, Molds, Epidermals, Insects, Foods and Miscellaneous Inhalants) safely and effectively. See full prescribing information for Non-Standardized Allergenic Extracts.

Non-Standardized Allergenic Extracts (Pollens, Molds, Epidermals, Insects, Foods, and Miscellaneous Inhalants)

Solutions for percutaneous, intradermal or subcutaneous administration.

Initial U.S. Approval: 1968

RECENT MAJOR CHANGES

Warning and Precautions, Anaphylaxis Following False Negative Food Allergen Skin Test Results (5.3) 01/2023

INDICATIONS AND USAGE

• Non-Standardized Allergenic Extracts are indicated for:

Skin test diagnosis of patients with a clinical history of allergies to one or more of the specific allergens. (1)

• Immunotherapy for reduction of allergen-induced allergic symptoms confirmed by appropriate positive skin tests or in vitro testing for allergen-specific IgE antibodies. (1)

Food extracts have not been proven safe or effective in allergen immunotherapy.

DOSAGE AND ADMINISTRATION

For percutaneous, intradermal or subcutaneous use only.

The extracts are diluted with sterile diluents when used for intradermal testing or subcutaneous immunotherapy. For percutaneous testing, the extracts are diluted with sterile diluents in patients expected to be at greater risk for systemic allergic reaction. Dosages vary by mode of administration and by individual response. See full prescribing information for instructions on preparation, administration, and adjustments of dose. (2.1)

DOSAGE FORMS AND STRENGTHS

Non-Standardized Allergenic Extracts are labeled in weight/volume and/or protein nitrogen units (PNU)/milliliter (a measure of total protein), and are supplied as sterile aqueous stock concentrates at up to 1:10 weight/volume or 40,000 PNU/milliliter, or 50% glycerin stock concentrates at up to 1:20 weight/volume. (3)

CONTRAINDICATIONS

• Severe, unstable or uncontrolled asthma. (4)
• History of any severe systemic or local allergic reaction to an allergen extract. (4)

WARNINGS AND PRECAUTIONS

Severe allergic reactions have occurred following the administration of other allergenic extracts and may occur in individuals following the administration of Non-Standardized Allergenic Extracts in the following situations:

• Extreme sensitivity to Non-Standardized Allergenic Extracts, receipt of high doses of Non-Standardized Allergenic Extracts, or concomitant exposure to similar environmental allergens. (5.1)
• Receiving an accelerated immunotherapy build-up schedule (e.g., “rush” immunotherapy), or changing from one allergenic lot to another. (5.1)

ADVERSE REACTIONS

The most common adverse reactions, occurring in 26 to 82% of all patients who receive subcutaneous immunotherapy, are local adverse reactions at the injection site (e.g., erythema, itching, swelling, tenderness, pain). (6)

Systemic adverse reactions, occurring in < 7% of patients who receive subcutaneous immunotherapy, include generalized skin erythema, urticaria, pruritus, angioedema, rhinitis, wheezing, laryngeal edema, and hypotension.

These can be fatal. (6)

To report SUSPECTED ADVERSE REACTIONS, contact GREER Laboratories, Inc. at 1-855-274-1322 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.

DRUG INTERACTIONS

• Antihistamines and other medications that suppress histamine, including topical corticosteroids, topical anesthetics and tricyclic antidepressants can interfere with skin test results. (7)

See 17 for PATIENT COUNSELING INFORMATION

WARNING: SEVERE ALLERGIC REACTIONS
1 INDICATIONS AND USAGE
2 DOSAGE AND ADMINISTRATION
2.1 Preparation for Administration
2.2 Diagnostic Testing
2.3 Immunotherapy
3 DOSAGE FORMS AND STRENGTHS
4 CONTRAINDICATIONS
5 WARNINGS AND PRECAUTIONS
5.1 Serious Systemic Adverse Reactions
5.2 Epinephrine
5.3 Cross-Reactions and Dose Sensitivity
6 ADVERSE REACTIONS
7 DRUG INTERACTIONS
7.1 Antihistamines
7.2 Topical Corticosteroids and Topical Anesthetics
7.3 Tricyclic Antidepressants
8 USE IN SPECIFIC POPULATIONS
8.1 Pregnancy
8.2 Lactation
8.4 Pediatric Use
8.5 Geriatric Use
11 DESCRIPTION
12 CLINICAL PHARMACOLOGY
12.1 Mechanism of Action
14 CLINICAL STUDIES
15 REFERENCES
16 HOW SUPPLIED/STORAGE AND HANDLING
16.1 How Supplied
16.2 Storage and Handling
17 PATIENT COUNSELING INFORMATION
*Sections or subsections omitted from the Full Prescribing Information are not listed.

WARNING: SEVERE ALLERGIC REACTIONS

• Non-Standardized Allergenic Extracts can cause severe life-threatening systemic reactions, including anaphylaxis. (5.1)
• Do not administer these products to patients with severe, unstable, or uncontrolled asthma. (4)
• Observe patients in the office for at least 30 minutes following treatment. Emergency measures and personnel trained in their use must be available immediately in the event of a life-threatening reaction. (5.1)
• Patients with extreme sensitivity to these products, those on an accelerated immunotherapy build-up schedule, those switching to another allergenic lot, those receiving high doses of Non-Standardized Allergenic Extracts, or those also exposed to similar allergens may be at increased risk of a severe allergic reaction. (5.1)
• These products may not be suitable for patients with certain underlying medical conditions that may reduce their ability to survive a serious allergic reaction. (5.1)
• These products may not be suitable for patients who may be unresponsive to epinephrine or inhaled bronchodilators, such as those taking beta-blockers. (5.2)

Non-Standardized Allergenic Extracts are indicated for:

• Skin test diagnosis of patients with a clinical history of allergies to one or more of the specific non-standardized allergens.
• Immunotherapy for the reduction of allergen-induced allergic symptoms confirmed by appropriate positive skin tests or by in vitro testing for allergen-specific IgE antibodies.

Food extracts have not been proven safe or effective in allergen immunotherapy.

For percutaneous, intradermal or subcutaneous use only.

The extracts are diluted with sterile diluents when used for intradermal testing or subcutaneous immunotherapy. For percutaneous testing, the extracts are diluted with sterile diluents in patients expected to be at greater risk for systemic allergic reaction. Dosages vary by mode of administration and by individual response.

2.1 Preparation for Administration

Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration, whenever solution and container permit. Discard solution if either of these conditions exist.

The extracts are diluted with sterile diluents when used for percutaneous and intradermal testing, or for subcutaneous immunotherapy.

Extracts labeled “For Diagnostic Use Only” are intended for percutaneous and intradermal testing only. These extracts have not been shown by adequate data to be safe and effective for therapeutic use. The extracts labeled For Diagnostic Use Only are the foods Barley, Coffee, Oat, Pineapple, Rye, Spinach, Wheat, the insects Flea, House Fly, Mosquito, and the plant and plant parts Cottonseed and Flax.

Undiluted 50% glycerin stock concentrate is used for percutaneous testing. To prepare 10-fold dilutions for percutaneous testing in patients suspected to be at greater risk for systemic allergic reaction, start with the stock concentrate. Proceed as shown in Table 1. The 10-fold dilution series uses 0.5 milliliters of concentrate added to 4.5 milliliters of sterile 50% glycerin diluent. Subsequent dilutions are made in a similar manner.

To prepare 10-fold dilutions for intradermal testing and immunotherapy, start with a 1:10 weight/volume, 1:20 weight/volume, or up to a 40,000 PNU/milliliter stock concentrate. Proceed as shown in Table 1. The 10-fold dilution series uses 0.5 milliliter of concentrate added to 4.5 milliliters of sterile diluent (glycerin-free diluents for intradermal testing, glycerin-free or 10% glycerin-saline diluents for immunotherapy). Subsequent dilutions are made in a similar manner.

*There is no direct potency correlation across the table between PNU/milliliter and w/v.

Undiluted 50% glycerin stock concentrate is used for percutaneous testing. To prepare 5-fold dilutions for percutaneous testing in patients suspected to be at greater risk for systemic allergic reaction, start with the stock concentrate. Proceed as shown in Table 2. The 5-fold dilution series uses 1 milliliter of concentrate added to 4 milliliters of sterile 50% glycerin diluent. Subsequent dilutions are made in a similar manner.

To prepare 5-fold dilutions for intradermal testing or immunotherapy, start with a 1:10 weight/volume, 1:20 weight/volume, or up to a 40,000 PNU/milliliter stock concentrate. Proceed as shown in Table 2. The 5-fold dilution series uses 1 milliliter of concentrate added to 4 milliliters of sterile diluent (glycerin-free diluents for intradermal testing, glycerin-free or 10% glycerin-saline diluents for immunotherapy). Subsequent dilutions are made in a similar manner.

*There is no direct potency correlation across the table between PNU/milliliter and w/v.

2.2 Diagnostic Testing

Diagnostic testing can be performed via percutaneous or intradermal administration of the Non-Standardized Allergenic Extracts. A positive skin test reaction should be interpreted in relation to the patient’s history and known exposure to the specific allergen(s).

Percutaneous Skin Testing

Preparation and Dose

For percutaneous testing (prick or puncture), use glycerinated extract; use the extracts at the highest available stock concentration. In patients suspected to be at greater risk for systemic allergic reaction, use 10-fold or 5-fold dilutions of the concentrate.

Prick test: Place one drop of extract with appropriate controls on the skin and with a skin test device, pierce through the drop into the skin with a slight lifting motion. Alternatively, use skin test devices loaded with the extract from the storage trays in a similar manner or in accordance with the device manufacturer’s recommendations.

Puncture test: Place one drop of extract or control on the skin and pierce the skin through the drop with a skin test device perpendicular to the skin. Alternatively, use skin test devices loaded with the extract from the storage trays in a similar manner or in accordance with the device manufacturer’s recommendations.

Interpreting Results

When using percutaneous skin test devices, follow the directions provided with the test devices. A glycerinated histamine control solution (6 milligrams/milliliter or 1 milligram/milliliter histamine base) may be used as the positive control. A 50% glycerin-saline solution may be used as the negative control.

Read and record skin test responses 15 to 20 minutes after exposure. Individual patient reactivity can vary with time, allergen potency, and/or immunotherapy, as well as testing technique. The most reliable method of recording a skin test reaction is to measure the largest diameter of both wheal and erythema. While some correlation exists between the size of the skin test reaction and the degree of sensitivity, other factors should be considered in the diagnosis of allergy to specific allergens (see Figure 1 below).

Figure 1: Measurement of Wheal and Flare

Use a paper or plastic millimeter skin reaction guide as shown below.

Figure_1 (Figure 1)

Fifteen minutes after application of the skin test, measure the length and midpoint orthogonal width of each flare and wheal from the inner edge of the reaction.

Length_and_midpoint_orthogonal_width (Length And Midpoint Orthogonal Width)

The length of the skin test is defined as the largest diameter and the width of the skin test is defined as the diameter perpendicular to the length at its midpoint. Consider the wheal and flare as separate entities. First, measure the flare and then independently measure the wheal.

Measuring the Flare

Measure_the_flare (Measure The Flare)

Measuring the Wheal

The average diameter measurement in the example above of the flare is (26 mm + 36 mm)/ 2 = 31 mm and the average diameter of the wheal is (10 mm + 16 mm)/2 = 13 mm.

Responses to positive controls should be at least 3 millimeters larger than responses to the negative controls.

Negative controls should elicit no reaction or only reactions of small diameter (less than 2 millimeters wheal, less than 5 millimeters erythema).

If either the positive or negative control response does not meet the above criteria, results for the allergenic extracts tested at the same time should be considered invalid and be repeated.

Intradermal Skin Testing

Preparation and Dose

For intradermal testing, dilute stock concentrate to 1:100 to 1:1000 volume to volume of Non-Standardized Allergenic Extracts stock concentrate solution. Dilute the stock concentrate solution with sterile diluent [see Dosage and Administration (2.1)]. Use normal or buffered saline or normal saline with human serum albumin (HSA) diluent. If the result from the initial test dose is negative, subsequent intradermal tests using increasingly stronger doses may be performed up to the maximum recommended strength of 1:25 volume to volume dilution of the extract concentrate solution.

Inject 0.02 milliliters of the extract solution intradermally according to the algorithms shown in Figure 2.

Figure 2: Algorithm for Dilution of Stock Concentrate Solution of Non-Standardized Allergenic Extracts for Intradermal Skin Testing

Figure_2 (Figure 2)

¹ Corresponds to 1:10,000 - 1:15,625 volume to volume dilution of 1:20 weight/volume glycerinated extract concentrates

² Corresponds to 1:100 - 1:125 volume to volume dilution of 1:20 weight/volume glycerinated extract concentrates

³ Corresponds to 1:50 - 1:100 volume to volume dilution of 1:20 weight/volume glycerinated extract concentrates

⁴ Corresponds to 1:25 - 1:100 volume to volume dilution of 1:20 weight/volume glycerinated extract concentrates

2.3 Immunotherapy

For subcutaneous administration only.

Preparation and Dose

Stock concentrates of Non-Standardized Allergenic Extracts are available in aqueous (up to 1:10 weight/volume or 40,000 PNU/milliliter) and 50% glycerin (up to 1:20 weight/volume) strengths for immunotherapy. Stock concentrates are diluted in normal saline, buffered saline, HSA-saline, or 10% glycerin-saline, depending on the patient’s reactivity to the diluent. See Table 1 and Table 2 for dilution preparation.

Administration of Immunotherapy

Administer immunotherapy by subcutaneous injection in the lateral aspect of the upper arm or thigh. Avoid injection directly into any blood vessel.

The optimal interval between doses of allergenic extract varies among individuals. Injections are usually given 1 to 2 times per week until the maintenance dose is reached, at which time the injection interval is increased to 2, then 3, and finally 4 weeks. Dosages vary by mode of administration, and by clinical response and tolerance. The minimum course of treatment may be three to five years, depending on the clinical response.

Guidelines for Immunotherapy

The initial dose of the extract should be based on the skin test reactivity. In patients suspected to be at greater risk for systemic allergic reaction by history and skin test, the initial dose of the extract should be 0.05 milliliter of a 1:20,000,000 to 1:2,000,000 weight/volume extract dilution. Patients not suspected to be at greater risk for systemic allergic reaction may be started at 0.1 milliliter of a 1:200,000 to 1:20,000 weight/volume extract dilution.

The dose of allergenic extract is increased at each injection by no more than 50% of the previous dose, and the next increment is governed by the response to the last injection.

Select the maximum tolerated maintenance dose based on the patient’s clinical response and tolerance. Doses larger than 0.2 milliliter of the stock concentrate are rarely administered because an extract in 50% glycerin diluent can cause discomfort upon injection.

Dosage Modification Guidelines for Immunotherapy

The following conditions may indicate a need to withhold or reduce the dosage of immunotherapy.

• Symptoms of rhinitis and/or asthma
• Infection accompanied by fever
• Exposure to excessive amounts of clinically relevant environmental allergen prior to a scheduled injection
• Large local reactions that persist for longer than 24 hours can be an indication for repeating the previous dose or reducing the dose at the next administration

Any evidence of a systemic reaction is an indication for a significant reduction (at least 75%) in the subsequent dose. Repeated systemic adverse reactions are sufficient reason for the cessation of further attempts to increase the dose.

Local adverse reactions require a decrease in the next dose by at least 50%. Proceed cautiously in subsequent dosing. In situations prompting dose reduction, once the reduced dose is tolerated, a cautious increase in dosage can be attempted.

Changing extract to a different lot or from a different manufacturer: When switching to a different lot of extract, or from another manufacturer’s extract, decrease the starting dose. Because manufacturing processes and sources of raw materials differ among manufacturers, the interchangeability of extracts from different manufacturers cannot be assured. In general, a dose reduction of 50 to 75% of the previous dose should be adequate, but each situation must be evaluated separately, considering the patient’s history of sensitivity, tolerance of previous injections, and other factors. Dose intervals should not exceed one week when rebuilding the dose.

Unscheduled gaps between treatments: Patients can lose tolerance to allergen injections during prolonged periods between doses, which increases their risk for an adverse reaction. The duration of tolerance between injections varies from patient to patient.

During the build-up phase, when patients receive injections 1 to 2 times per week, repeat or reduce the extract dosage if there has been a substantial time interval between injections. This depends on: 1) the concentration of allergen immunotherapy extract that is to be administered; 2) a previous history of systemic reactions; and 3) the degree of variation from the prescribed interval of time, with longer intervals since the last injection leading to greater reductions in the dose to be administered.

This suggested approach to dose modification, due to unscheduled gaps between treatments during the build-up phase, is not based on published evidence. The individual physician should use this or a similar protocol for the specific clinical setting.

Similarly, if unscheduled gaps occur during maintenance therapy, it may be necessary to reduce the dosage and bring the patient up to maintenance dosing using an established build-up protocol.

Changing from non-stabilized to human serum albumin (HSA) stabilized diluents: Allergenic extracts prepared with diluents containing HSA and 0.4% phenol are more stable than those prepared with diluents that do not contain stabilizers. When switching from a non-stabilized to an HSA-stabilized diluent, consider lowering the dose for immunotherapy.

Non-Standardized Allergenic Extracts are labeled in weight/volume and/or protein nitrogen units (PNU)/milliliter (a measure of total protein), and are supplied as sterile aqueous stock concentrates at up to 1:10 weight/volume or 40,000 PNU/milliliter, or 50% glycerin stock concentrates at up to 1:20 weight/volume.

Non-Standardized Allergenic Extracts are contraindicated in patients with:

• Severe, unstable or uncontrolled asthma
• History of any severe systemic or local allergic reaction to an allergen extract

5.1 Serious Systemic Adverse Reactions

Serious systemic adverse reactions have occurred following the administration of other allergenic extracts and may occur in individuals following the administration of Non-Standardized Allergenic Extracts in the following situations:

• Extreme sensitivity to the specific allergen(s)
• Receipt of an accelerated immunotherapy build-up schedule (e.g., “rush” immunotherapy)
• Receipt of high doses of allergenic extracts or concomitant exposure to similar environmental allergens
• Change from one allergenic extract lot to another allergenic extract lot

High-risk patients have had fatal reactions. Consider using more dilute preparations in patients suspected to be at greater risk of systemic allergic reaction [see Dosage and Administration (2.1)].

Administer Non-Standardized Allergenic Extracts in a healthcare setting under the supervision of a physician prepared to manage a severe systemic or a severe local allergic reaction.Observe patients in the office for at least 30 minutes following administration. ¹

5.2 Epinephrine

Non-Standardized Allergenic Extracts may not be suitable for patients with certain medical conditions that may reduce the ability to survive a serious allergic reaction or increase the risk of adverse reactions after epinephrine administration. Examples of these medical conditions include but are not limited to: markedly compromised lung function (either chronic or acute), unstable angina, recent myocardial infarction, significant arrhythmia, and uncontrolled hypertension.

These products may not be suitable for patients who are taking medications that can potentiate or inhibit the effect of epinephrine. These medications include:

Βeta-adrenergic blockers: Patients taking beta-adrenergic blockers may be unresponsive to the usual doses of epinephrine used to treat serious systemic reactions, including anaphylaxis. Specifically, beta-adrenergic blockers antagonize the cardiostimulating and bronchodilating effects of epinephrine.

Alpha-adrenergic blockers, ergot alkaloids: Patients taking alpha-adrenergic blockers may be unresponsive to the usual doses of epinephrine used to treat serious systemic reactions, including anaphylaxis. Specifically, alpha-adrenergic blockers antagonize the vasoconstricting and hypertensive effects of epinephrine. Similarly, ergot alkaloids may reverse the pressor effects of epinephrine.

Tricyclic antidepressants, levothyroxine sodium, monoamine oxidase inhibitors, and certain antihistamines: The adverse effects of epinephrine may be potentiated in patients taking tricyclic antidepressants, levothyroxine sodium, monoamine oxidase inhibitors, and the antihistamines chlorpheniramine, and diphenhydramine.

Cardiac glycosides, diuretics: Patients who receive epinephrine while taking cardiac glycosides or diuretics should be observed carefully for the development of cardiac arrhythmias.

5.3 Anaphylaxis Following False Negative Food Allergen Skin Test Results
False negative skin test results associated with anaphylaxis from subsequent exposure to the allergen have been reported during postmarketing diagnostic use of some food allergenic extracts. Based on the patient’s clinical history and index of suspicion, healthcare providers should consider confirming negative skin testing with serologic testing by measuring specific serum IgE or with a medically-supervised oral food challenge.

5.4 Cross-Reactions and Dose Sensitivity

When determining the final dose of an allergen mixture for immunotherapy, consider cross-reactivity among component extracts.

Determine the initial dilution of allergenic extract, starting dose, and progression of dosage based on the patient’s history and results of skin tests ² [see Dosage and Administration (2.1)]. Strongly positive skin tests can be indicators for potential adverse reactions.

The most common adverse reactions, occurring in 26 to 82% of all patients who receive subcutaneous immunotherapy are local adverse reactions at the injection site (e.g., erythema, itching, swelling, tenderness, pain). ¹ Systemic adverse reactions, occurring in < 7% of patients who receive subcutaneous immunotherapy, ³ include generalized skin erythema, urticaria, pruritus, angioedema, rhinitis, wheezing, laryngeal edema, and hypotension. These adverse reactions can be fatal. ¹

The allergenic extracts labeled “For Diagnostic Use Only” that contain sodium formaldehyde sulfoxylate (SFS) can cause slight discoloration of the skin at the site of administration. This discoloration can remain for extended amounts of time.

7.1 Antihistamines

Do not perform skin testing with allergenic extracts within 3 to 10 days of use of first-generation H1-histamine receptor blockers (e.g., clemastine, diphenhydramine) and second-generation antihistamines (e.g., loratadine, cetirizine). These products suppress histamine skin test reactions and could mask a positive response. ²

7.2 Topical Corticosteroids and Topical Anesthetics

Topical corticosteroids can suppress skin reactivity; therefore, discontinue use at the skin test site for 2 to 3 weeks before skin testing. Avoid use of topical local anesthetics at skin test sites as they can suppress flare responses. ²

7.3 Tricyclic Antidepressants

Tricyclic antidepressants can have potent antihistamine effects that can affect skin testing. If tricyclic medication has been recently discontinued, allow 7 to 14 days before initiating skin testing. ²

8.1 Pregnancy

Risk Summary

All pregnancies have a risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2 to 4% and 15 to 20%, respectively. There are no human or animal data to establish the presence or absence of Non-Standardized Allergenic Extracts-associated risks during pregnancy.

8.2 Lactation

Risk Summary

It is not known whether Non-Standardized Allergenic Extracts are present in human milk. Data are not available to assess the effects of these extracts on the breastfed child or on milk production/excretion. The developmental and health benefits of breastfeeding should be considered along with the mother’s clinical need for Non-Standardized Allergenic Extracts and any potential adverse effects on the breastfed child from the extracts or from the underlying maternal condition.

8.4 Pediatric Use

For use of these products in children younger than 5 years of age, consideration should be given to the patient’s ability to comply and cooperate with allergen immunotherapy and the potential for difficulty in communicating with the child regarding systemic reactions. ¹

8.5 Geriatric Use

Data are not available to determine if subjects 65 years of age and older respond differently to allergen immunotherapy than younger subjects.

Non-Standardized Allergenic Extracts are sterile solutions used for percutaneous testing, intradermal testing, or subcutaneous immunotherapy. Aqueous extracts contain the soluble extractants of the source material in water for injection, 0.5% sodium chloride, 0.54% sodium bicarbonate, and 0.4% phenol. Glycerinated extracts contain the soluable extractants of the source material in water for injection and 50% glycerin, 0.25% sodium chloride, 0.27% sodium bicarbonate, and 0.2% phenol. The pH of the extracts range from 6 to 9.

Certain food extracts (Barley, Oat, Pineapple, Rye, Spinach, and Wheat), labeled “For Diagnostic Use Only”, contain 0.1% sodium formaldehyde sulfoxylate as an antioxidant.

Source materials used in the manufacture of allergenic extracts are collected from natural sources or from laboratory cultures.

Non-Standardized Allergenic Extracts appear as clear and colorless to dark brown solutions that should be free of particulate matter.

Extracts are labeled either as weight-to-volume based on the weight of the source material to the volume of the extracting fluid, or as PNU/milliliter with one PNU representing 0.00001 mg of protein nitrogen per milliliter.

Specific immunotherapy with allergenic extracts is helpful in reducing symptoms associated with exposure to the offending allergens. A summary of effectiveness by the Panel on Review of Allergenic Extracts, an advisory committee to the U.S. Food and Drug Administration, has been published. ⁴

12.1 Mechanism of Action

The skin test reaction results from interaction of the introduced allergen and allergen-specific IgE antibodies bound to mast cells, leading to mast cell degranulation and release of histamine, tryptase and other mediators, which results in the formation of the wheal and flare.

The precise mechanisms of action of allergen immunotherapy are not known. Immunologic responses to immunotherapy include changes in allergen-specific IgE levels, allergen-specific IgG levels, and regulatory T cell responses. ¹

• Cox LJ, Nelson H, Lockey R.Allergen immunotherapy: A practice parameter third update. J Allergy Clin Immunol. 2011;127:(1)S1-55.
• Bernstein IL, Li JT, Bernstein DI, et al.Allergy diagnostic testing: an updated practice parameter. Ann Allergy Asthma Immunol. 2008;100:S1-148.
• Greenberg MA, Kaufman CR, Gonzalez GE, et al. Late and immediate systemic-allergic reactions to inhalant allergen immunotherapy. J Allergy Clin Immunol. 1986;77:865-870.
• Federal Register Proposed Rule: Biological Products: Implementation of Efficacy Review, Allergenic Extracts, Federal Register 1985;50: 3082-3288.

Non-Standardized Allergenic Extracts and mixes may be supplied as aqueous stock concentrates of up to 1:10 weight/volume or 40,000 PNU/milliliter for intradermal and subcutaneous testing. The extracts may also be supplied as 50% glycerin stock concentrates of up to 1:20 weight/volume for use in percutaneous skin testing and subcutaneous immunotherapy. Non-Standardized Allergenic Extracts are labeled in weight/volume and/or PNU/milliliter and may be provided in 5, 10, and 50 milliliter vials. Glycerinated extracts are also supplied in 5 milliliter dropper vials for prick or puncture testing.

Non-Standardized Allergenic Extracts available are as follows:

16.2 Storage and Handling

Maintain at 2 to 8°C (36 to 46°F) during storage and use.

Dilutions of concentrated extracts that result in a glycerin content of less than 50% can reduce extract stability. Extract dilutions at 1:100 volume to volume should be kept no longer than a month, and more dilute solutions no more than a week. The potency of a dilution can be checked by skin test comparison to a fresh dilution of the extract on a known allergic patient.

Instruct patient to remain under observation in the office for 30 minutes or longer after an injection.

Caution patient that reactions can occur more than 30 minutes after skin testing or an injection.

Instruct patient to recognize the following symptoms as adverse reactions and to immediately return to the office or immediately seek other medical attention if any of these symptoms occur following skin testing or an injection:

• Unusual swelling and/or tenderness at the injection site
• Hives or itching of the skin
• Swelling of the face and/or mouth
• Sneezing, coughing or wheezing
• Shortness of breath
• Nausea
• Dizziness or faintness

Manufacturer:

U.S. License No. 308

Greer Laboratories, Inc.

Lenoir, NC 28645 U.S.A