INDICATIONS
Hyposensitization (injection) therapy is a treatment for
patients exhibiting allergic reactions to seasonal pollens, dust mites, molds,
animal danders, and various other inhalants, in situations where the offending allergen
cannot be avoided.
Prior to the initiation of therapy, clinical sensitivity
should be established by careful evaluation of the patient's history confirmed
by diagnostic skin testing. Hyposensitization should not be prescribed for sensitivities
to allergens which can be easily avoided.
DOSAGE AND ADMINISTRATION
The starting dose for immunotherapy is related directly
to a patient's sensitivity as determined by carefully executed percutaneous
(prick/puncture) and intracutaneous (intradermal) skin testing with nonalum adsorbed
allergenic extract. A general rule is to begin at 1/10 of the intradermal dose
that produces sum of erythema of 50 mm (approximately a 2+ positive skin test
reaction). Patient's response to skin testing is graded on the basis of the
size of the erythema and wheal. Refer to the diagnostic allergenic extract
package enclosure for specific information.
TRANSFER OF PATIENTS FROM OTHER AQUEOUS EXTRACTS TO CENTER-AL EXTRACTS
Patients may be transferred from other aqueous allergens
to Center-Al Alum Precipitated Extracts during treatment. To avoid
untoward reactions, it may be necessary to initiate treatment as though the patient
were previously untreated. In transferring from standardized extracts, the more
rapid rate of decline in activity of aqueous extract relative to alum
precipitated extract must be considered in cautiously transferring patients to
alum precipitated extract.
Caution should be observed since the Center-Al preparation
may be more potent than the aqueous product.
TRANSFER OF PATIENTS FROM OTHER ALUM-COMPLEXED EXTRACTS TO CENTER-AL EXTRACTS
Patients may be transferred from other alum-complexed
allergenic extracts to Center-Al Alum Precipitated extracts. In order to
avoid untoward reactions, it is recommended that previous therapy be disregarded
and therapy with Center-Al be initiated as though the patient were previously
untreated. The first dose of Center-Al should be related to the
patient's sensitivity, determined by history and confirmed by skin testing.
CAUTION: Center-Al Alum Precipitated extracts should not be mixed with other
alum precipitated or aqueous extracts.
Pre-Seasonal And Perennial Method Of Treatment
The use of Center-Al Allergenic extract, Alum
Precipitated, in the treatment of patients by the preseasonal method should be
started 10 to 12 weeks prior to the usual onset of symptoms. Therapy should be
initiated early enough to permit a graduated series of doses at weekly
intervals. It is recommended that the larger doses be spaced 2 to 3 weeks apart
and that the top dose be reached prior to the season.
Increased tolerance acquired through hyposensitization
can vary from a few to several months. To assure prolongation of this acquired
tolerance, perennial or year-round treatment is recommended.
Some physicians continue therapy into or through the
season by repeating a reduced MAINTENANCE dose at 4 to 6 week intervals.
Suggested Dosage Schedule
A treatment schedule is related directly to the patient's
degree of sensitivity, determined initially by clinical history and skin
testing, and continuously by response to therapeutic doses. Thus, an individual
treatment schedule for each patient must be established during the course of
therapy. Maximum protection can be obtained with a dosage kept constantly below
the patient's limit of tolerance. Every precaution should be taken to avoid a
systemic or generalized reaction which in addition to being dangerous, may
depress rather than increase the patient's tolerance.
For All Preparations (Except Short Ragweed And Mixed
Short And Tall Ragweed)
Labeled Antigen E content of extracts containing Short
Ragweed at a weight/volume concentration more dilute than 1:10 may have been
obtained by calculation from the Antigen E assay value of a more concentrated
extract that was analyzed, officially released by the Office of Biologics, and
subsequently diluted.
Below is listed a suggested dosage schedule for
Pre-Seasonal Treatment. A column has been left blank for AgE dosage of short
ragweed containing extracts.
Note: For extracts of short ragweed or equal part
mixture of Short and Tall Ragweed refer to AgE dosage schedule. The AgE content
for those products is indicated on the vial label. The physician may use the
formula below to determine the AgE dosage for each injection.
AgE dosage can be monitored by using the formula:
Labeled AgE / Labeled PNU/mL X dose in PNU = dose in
AgE
Note: Suggested dosage schedules which follow have
not been subjected to adequate and well controlled trials to establish their
safety and efficacy.
Dose No. |
Vial Strength |
Volume Injected |
PNU Per Dose |
AgE Dose |
1 |
100 PNU/mL |
0.1 mL |
10 |
|
2 |
100 PNU/mL |
0.2 mL |
20 |
|
3 |
100 PNU/mL |
0.5 mL |
50 |
|
4 |
1,000 PNU/mL |
0.1 mL |
100 |
|
5 |
1,000 PNU/mL |
0.25 mL |
250 |
|
6 |
1,000 PNU/mL |
0.5 mL |
500 |
|
7 |
10,000 PNU/mL |
0.1 mL |
1,000 |
|
8 |
10,000 PNU/mL |
0.2 mL |
2,000 |
|
9 |
10,000 PNU/mL |
0.3 mL |
3,000 |
|
10 |
10,000 PNU/mL |
0.4 mL |
4,000 |
|
11 |
10,000 PNU/mL |
0.5 mL |
5,000 |
|
MAINTENANCE DOSE: |
|
10,000 PNU/mL |
0.5 mL |
5,000 |
|
NO SINGLE DOSE SHOULD EXCEED 5,000 PNU. For continuing
therapy with extracts containing Short Ragweed, see following section on Dosage
Adjustments.
SHORT RAGWEED EQUAL PARTS MIXES OF SHORT AND TALL RAGWEED
(DOSAGE BASED ON ANTIGEN CONTENT)
Suggested dosage schedule for Short Ragweed and Equal
Part Mixture of Short and Tall Ragweed:
Dose No |
AgE Units/mL |
Volume Injected |
AgE Per Dose |
1 |
0.4 |
0.1 |
0.04 |
2 |
0.4 |
0.2 |
0.08 |
3 |
0.4 |
0.5 |
0.2 |
4 |
4 |
0.1 |
0.4 |
5 |
4 |
0.25 |
1 |
6 |
4 |
0.5 |
2 |
7 |
40 |
0.1 |
4 |
8 |
40 |
0.2 |
8 |
9 |
40 |
0.3 |
12 |
10 |
40 |
0.4 |
16 |
11 |
40 |
0.5 |
20 |
MAINTENANCE DOSE: |
|
40 |
0.5 |
20 |
|
80 |
0.25 |
20 |
NO SINGLE DOSE SHOULD EXCEED 20 UNITS
DOSAGE ADJUSTMENTS
(FOR PRODUCTS CONTAINING SHORT RAGWEED)
AgE is important in adjusting dosage of Short Ragweed
extracts to accurately transfer a patient from older extracts to fresher
material. In such cases, the dosage of AgE should be considered in addition to the
protein nitrogen units. Antigen E concentration continuously declines in Short
Ragweed Pollen extracts at a rate that varies with the formulation of the
product. Aqueous extracts retain Antigen E potency less effectively than 50%
glycinerated or Alum Precipitated extracts. Antigen E is most stable in
freeze-dried extracts. These differences are reflected in the expiration date
declared on the vial label. The continuous decline should be considered. Also,
where Ragweed is a component of an allergen mixture, clinical response to the
other components must be considered in adjustment of dosage based on AgE
content alone.
CAUTION: A small percent of individuals allergic to Short
Ragweed are more sensitive to minor antigens such as Ra3 and Ra5 than AgE.
There is no correlation between the amount of these antigens and either AgE or
PNU content.
HOW SUPPLIED
Therapeutic Center-Al Allergenic Extracts, Alum
Precipitated, are supplied in 10 mL and 30 mL vials, in concentrations of
10,000 PNU/mL and 20,000 PNU/mL. Prescription treatment sets for individual patients
are also available. Center-Al must be stored continuously at 2° to 8°C.
DO NOT FREEZE. Diluent: Sterile Diluent for allergenic extracts (Phenol-Saline)
is provided in vials of 4.5 mL, 9.0 mL, and 30 mL.
Storage
To maintain stability of allergenic extracts, proper
storage conditions are essential. Bulk concentrates and diluted extracts are to
be stored at 2° to 8°C even during use. Bulk or diluted extracts are not to be
frozen. Do not use after the expiration date shown on the vial label.
REFERENCES
4. Ransom, J.H.: Clinical and laboratory evaluation of
alum precipitated ragweed extract. Ann. Allergy 28:22, 1970.
5. Ransom, J.H.: Frequency of reactions to alum
precipitated ragweed extract. Ann. Allergy 29:635, 1971.
Distributed in Canada by: ALK-Abelló Pharmaceuticals,
Inc., #35 – 151 Brunel Road, Mississauga, Ontario, Canada L4Z 2H6. Revision:
Jun 2013