INDICATIONS AND USAGE:
Standardized grass pollen extracts are used for the diagnosis and treatment of allergic disease to grass pollen. The standardized (Bioequivalent Allergy Unit) extract in these vials is designed primarily for the physician equipped to prepare dilutions and mixtures as required. STANDARDIZED GRASS POLLEN EXTRACTS L A BELED IN BAU/ml ARE NOT INTERCHANGEABLE WITH GRASS POLLEN EXTRACTS LABELED IN AU/ml OR WITH NON-STANDARDIZED (WEIGHT/VOLUME) GRASS POLLEN EXTRACTS. Patients being switched from other types of extracts to Allergy Laboratories should have their dose adjusted. Diagnosis of allergic disease to these grasses is made through a combined medical history sufficiently complete to identify allergic symptoms to grass pollen and identification of grass allergy by diagnostic skin testing. It is recommended that diagnostic skin testing (scratch or puncture) be performed with 10,000 BAU/ml grass pollen extracts before testing with 100,000 BAU/ml grass pollen extracts. 10,000 BAU/mL and 100,000 BAU/ml grass pollen extracts for immunotherapy are available for previously treated patients to facilitate dose selection for safe switching from non-standardized to standardized extracts. Patients being treated with grass pollen extracts for the first time can be initially immunized with dilutions prepared from the 10,000 BAU/ml extract (see Dosage and Administration). 100,000 BAU/ml grass pollen extract can be administered if the patient tolerates the 10,000 BAU/ml extract.
Grass pollen immunotherapy is intended for patients whose grass allergic symptoms cannot be satisfactorily controlled by avoidance of the offending allergen or by the use of symptomatic medications. (5)
CONTRAIND ICA TIONS:
There are no known absolute contraindications to hyposensitization therapy. See precautions section for pregnancy risks.
A patient without a history of grass pollen allergy symptoms and a positive skin test reaction to grass pollen should not be treated. The physician must determine if the benefits outweigh the risks in using these products for treating patients. The benefit to risk ratio should be carefully weighed especially where risks of immunotherapy are higher than usual. This includes severe unstable asthma, highly allergic patients who have had previous severe or unusual problems with injections, pregnancy, or any fragile general medical condition. This also includes patients where potential benefits are limited due to coexisting non-allergic disease such as: non-specific vasomotor rhinitis, nasal septal deviation, nasal polyps, COPD (chronic obstructive pulmonary disease), cardiovascular or other non-allergic respiratory disease.
See WARNINGS box at the beginning of the instruction sheet.
Extracts standardized using the Bioequivalent Allergy Unit may be more or less potent than extracts based on AU/ml, weight to volume, or PNU methods of expressing potency. See Adverse Reactions section in this insert for a description of the possible local reactions and systemic reactions. 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 COMPARATIVE SKIN TESTING IS PERFORMED. After inserting the needle, but before injecting 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.
The dosage should be reduced 50-75% from the previous dose when starting a patient on a new lot of standardized grass extract from the same manufacturer or from a different manufacturer. Table A in the Clinical Pharmacology section of this insert can be used for guidance when changing from a non-standardized grass extract to a standardized grass extract. The table shows the similarity in potency of two Iots of the non-standardized grass extracts with respect to the 10,000 BAU/ml standardized extracts. Comparative skin testing can be used to determine the dose.
A separate sterile tuberculin type syringe should be used with each patient to prevent cross contamination of extracts. This will also prevent transmission of disease such as hepatitis, AIDS and other infectious diseases. Aseptic technique should always be used when injections of allergenic extracts are administered.
Because most serious reactions following the administration of allergenic extracts occur within 30 minutes of the injection, the patient should remain under observation for this period of time. The size of the local reaction should be recorded, because increasingly large local reaction may precede a subsequent systemic reaction with increasing dosage. The patient should be instructed to report any unusual reactions to the attention of the physician. In particular, this includes swelling and/or tenderness at the injection site or reactions such as rhinorrhea, sneezing, coughing, wheezing, shortness of breath, nausea, dizziness or faintness.
Patients who are taking non-selective beta blockers may be more reactive to skin tests and may be unresponsive to the usual doses of epinephrine used to treat allergic reactions. Antihistamines can significantly inhibit the immediate skin test reactions. If long acting antihistamines have been taken recently, it is recommended that they should be stopped for the following minimum intervals before skin testing is performed: at least 1 month for astemizole; 1 week for hydroxyzine or cetirizine; 4 to 7 days for Ioratadine; 3 to 4 days for terfenadine or fexofenadine; and 24 to 48 hours for other sustained release antihistamines. (6)
CARCINOGENESIS, MUTAGENESIS, IMPAIRMENT OF FERTILITY:
Long term studies with extracts have not been conducted in animals to determine their potential for carcinogenesis, mutagenesis, or impairment of fertility.
Pregnancy Category C. Animal reproduction studies have not been conducted with allergenic extracts. It is also not known whether allergenic extracts can cause fetal harm when administered to a pregnant woman or can affect reproduction capacity. Allergenic extracts should be given to a pregnant woman only if clearly needed.
Controlled studies of hyposensitization with moderate to high doses of allergenic extracts in pregnant women have failed to demonstrate any risk to the mother or fetus. (7)
Initiation of effective immunotherapy may be beneficial if it allows a pregnant patient to forego medications during the first trimester when the fetus is more vulnerable to teratogenic agents, or if it contributes to better control of asthma so the fetus has less likelihood of being damaged by hypoxemia.
However, with histamines known ability to contract uterine muscles any reaction which would release significant amounts of histamine such as hyposensitization overdose should be avoided. The physician must weigh the benefits of immunotherapy against the risk of anaphylactic reactions that could result in harm to the mother and/or fetus.
Hyposensitization should be used during pregnancy only if clearly necessary and administered cautiously. If a woman is on maintenance dose the occurrence of pregnancy is not an indication to stop injection therapy.
It is not known if allergenic extracts are excreted in human milk. Because many drugs are excreted in human milk, caution should be exercised when extracts are administered to nursing women.
Standardized grass pollen extract has not been studied in children, so the safety in children has not been established. The extracts may cause some pain or discomfort when injected, as well as systemic, adverse reactions (see Warnings and Adverse Reactions). The maximum tolerated dose may be less than the adult dose due to the smaller size of the child. Therefore, the volume of the dose may need to be adjusted from the adult schedules provided.
(1) 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.
(2) 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 in the opposite arm. 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 0.1 ml 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. (8)
Serious adverse reactions can be reported to the US Food and Drug Administration MedWatch Program. The MedWatch forms can be obtained by calling 1-800-FDA-1088. The address is: MedWatch, 5600 Fishers Lane, Rockville, MD, 20852-9787.
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