Poa Pratensis

Standardized grass pollen extract is indicated for use in the diagnosis of grass allergy in patients with a history of allergic symptoms that occur during grass pollination. Skin tests with standardized grass pollen extract should be done first by the puncture method using 10,000 BAU/mL extract. If these tests are negative, they may be repeated by the puncture method with 100,000 BAU/mL extract, or by the intradermal method using an appropriate dilution (see DOSAGE AND ADMINISTRATION). The extract also is indicated for use in the treatment of allergic symptoms by immunotherapy in patients with a history of grass pollen allergy and established sensitivity to grass pollen extract by skin testing. The availability of 10,000 and 100,000 BAU/mL extracts facilitates dose selection for safe switching to standardized grass pollen extracts. Previously untreated patients should be initially treated with appropriately diluted 10,000 BAU/mL. If tolerated, higher doses may be indicated. The use of grass pollen extract for the above purposes should be made only by physicians with special familiarity and knowledge of allergy as described in a standard allergy textbook (13). Allermed's standardized grass pollen extracts labeled in BAU/mL are not interchangeable with alum-precipitated grass pollen extracts, grass pollen extracts labeled in AU/mL or non-standardized grass pollen extracts.

Immunotherapy should not be started in patients until a specific diagnosis of Type I allergy to grass pollen has been made from the patient's allergy history and from a positive skin test to grass pollen extract. Other contraindications include: EXTREME SENSITIVITY TO GRASS POLLEN: Patients who experience serious adverse reactions to grass pollen extract from skin testing and/or immunotherapy should not be given the product. 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 adverse reactions resulting from skin testing or immunotherapy. The benefit-torisk ratio must be carefully evaluated in these patients. CHILDREN WITH NEPHROTIC SYNDROME: Children with nephrotic syndrome require careful consideration and probably should not receive immunotherapy, due to a variety of seemingly unrelated events that may cause an exacerbation of nephrotic disease. BLEEDING DIATHESIS: Injections of grass pollen extract should not be administered in the presence of diseases characterized by a bleeding diathesis.

Standardized grass pollen extract must be diluted prior to first use on a patient for immunotherapy or intradermal testing (see DOSAGE AND ADMINISTRATION). Grass pollen extract is manufactured to assure high potency and has the ability to cause serious local and systemic reactions, including death in sensitive patients (14). Patients should be informed of this risk and precautions should be discussed prior to initiating skin testing and immunotherapy (see PRECAUTIONS). Grass pollen extract should be temporarily withheld from a patient if any of the following conditions exist: (a) severe symptoms of rhinitis and/or asthma; (b) infection or flu accompanied by fever; (c) exposure to excessive amounts of grass pollen allergen prior to a scheduled injection. SWITCHING PATIENTS TO STANDARDIZED GRASS POLLEN EXTRACT: The same precautions that are recommended in switching from an old to a new lot of non-standardized grass pollen extract should be followed in switching from non-standardized to standardized grass pollen extract, i.e., the dose of the new lot of standardized grass pollen extract should be reduced 75% of the dose given from an old lot of non-standardized grass pollen extract. Under certain circumstances, it may be advisable to compare the relative potency of the standardized and non-standardized extract by side by side skin testing using comparable v/v dilutions of the concentrates. When switching from alum precipitated grass pollen extract to standardized grass pollen extract, the patient should be managed as a new patient coming under treatment for the first time.

GENERAL: The risk of a severe allergic reaction usually can be reduced by eliciting the patient's allergy history and by percutaneous testing by the scratch, prick or puncture method. If a scratch, prick or puncture skin test is negative, it usually is safe to perform an intradermal test with a one thousand-fold dilution of the extract used for the percutaneous test. If there is a history of unusual sensitivity, it is advisable to use a weaker dilution of the extract for skin testing. Systemic allergic reactions may occur as a result of immunotherapy. The risk can be reduced by adherence to a careful injection schedule, which starts with a low concentration of extract and is increased slowly. The physician must be prepared to treat anaphylaxis should it occur and have the necessary drugs and equipment on hand to treat serious adverse reactions. Extracts should not be administered by the patient or by other individuals who are not prepared to treat anaphylaxis, should it occur. Extract must be injected subcutaneously during immunotherapy. It must not be given intravenously. A separate sterile tuberculin syringe graduated in 0.01 mL should be used for each injection. INFORMATION FOR PATIENTS: Because most serious reactions occur within 20 minutes after the injection of allergenic extract the patient should remain under observation for this length of time. The patient also should be instructed to report any unusual reactions to the physician, such as swelling and/or tenderness at the injection site or rhinorrhea, sneezing, coughing, wheezing, shortness of breath, nausea, dizziness or faintness following the injection of extract. CARCINOGENESIS, MUTAGENESIS, IMPAIRMENT OF FERTILITY: Long term studies in animals have not been conducted with standardized grass pollen extract to determine the potential for carcinogenicity, mutagenicity or impairment of fertility. PREGNANCY CATEGORY C: Animal reproduction studies have not been conducted with standardized grass pollen extract. It is also not known whether standardized grass pollen extract can cause fetal harm when administered to a pregnant woman or can affect reproduction capacity. Caution should be exercised in testing or treating pregnant females, because a systemic reaction might conceivably cause uterine muscle contractions leading to abortion. Standardized grass pollen extract should be given to a pregnant woman only if clearly needed (15). PEDIATRIC USE: The dose of allergenic extract recommended for children is the same as for adults. Allowances may be made in the injection of large doses of extract for treatment. In this case, it may be advisable to modify the dose and frequency of injections, so that the discomfort is minimized. NURSING MOTHERS: It is not known whether standardized grass pollen extract is excreted in human milk. Because many drugs are excreted in human milk, caution should be exercised when allergenic extract is administered to a nursing woman. DRUG INTERACTION: Antihistamines and hydroxyzine can inhibit the immediate skin test reaction. Patients being treated with delayed absorption antihistamine tablets should be free of such medication for 48 hours before testing. Non-sedating antihistamines, such as terfenadine and astemizole, may variably suppress the skin response for longer periods of time up to six weeks. Epinephrine injection inhibits the immediate skin test reaction for several hours. Beta-blocking drugs may make a patient refractory to the usual dose of epinephrine, in the event epinephrine is required to treat an adverse allergic reaction.

Local reactions consisting of erythema, itching, swelling, tenderness and sometimes pain may occur at the injection site. These reactions may appear within a few minutes to hours and persist for several days. Local cold applications and oral antihistamines may be effective treatment. For marked and prolonged local reactions, steroids may be helpful. Adverse systemic reactions usually occur within minutes and consist primarily of allergic symptoms such as generalized skin erythema, urticaria, pruritus, angioedema, rhinitis, wheezing, laryngeal edema and hypotension. Less commonly, nausea, emesis, abdominal cramps, diarrhea and uterine contractions may occur. Severe reactions may cause shock and loss of consciousness and fatalities have occurred (14). The treatment of systemic allergic reactions is somewhat dependent upon the symptom complex. Epinephrine hydrochloride 1:1,000 aqueous, in an adult dose of 0.3 – 0.5 mL (or 0.01 mL per kg. for children) administered subcutaneously in the opposite arm is the immediate treatment of choice. A tourniquet should be placed above the site of the injection if the injection was done on the extremities. Antihistamines may offer relief of recurrent urticaria, associated skin reactions and gastrointestinal symptoms. Persistent wheezing may necessitate intravenous aminophylline treatment in addition to inhaled bronchodilators. For profound shock and hypotension, intravenous fluids, vasopressors and oxygen also may be needed. Maintenance of an open airway is critical if upper airway obstruction is present. Corticosteroids may provide benefit if symptoms are prolonged or recurrent. Serious adverse reactions to this product should be reported to MEDWATCH, Food and Drug Administration, 5600 Fishers Lane, Rockville, MD 20852-9782. Telephone (800) 332-1088.