Immunotherapy Safety for the Primary Care ... - U.S. Coast Guard

J ALLERGY CLIN IMMUNOL
VOLUME 120, NUMBER 3
Cox et al S57
Individualized treatment vials
Summary Statement 41: Administration of an incorrect
injection is a potential risk of allergen immunotherapy. An
incorrect injection is an injection given to the wrong
patient or a correct patient receiving an injection of an
incorrect dose.
A customized individual maintenance concentrate of
the allergen immunotherapy extract and serial dilutions,
whether a single extract or a mixture of extracts, prepared
and labeled with the patient’s name and birth date might
reduce the risk of incorrect (wrong patient) injection. The
mixing of antigens in a syringe is not recommended
because of the potential for cross-contamination of
extracts. C
Individually prepared and labeled vials are recommended
because they have several potential advantages over
shared vials (ie, vials of allergen extract used for multiple
patients). Labels on patient-specific vials can provide at
least 2 patient identifiers (birth date and patient name),
which would be consistent with the recommendations of
the Joint Commission on Accreditation of Health Care
Organizations National Patient Safety Goals: ‘‘Goal 1:
Improve the accuracy of patient identification by using at
least two patient identifiers when providing care, treatment
or services.’’ 5 The risk of errors of administration might be
reduced because the individually prepared allergen immunotherapy
vials labeled with the patient’s name and birth
date will allow the person administering the extract and
the patient an opportunity to verify the name/birth date
on the label before administration of the injection. 4,5
In a survey of 1717 allergists endorsed by the AAAAI
and JCAAI, 57% of the 476 respondents reported at least
one wrong-patient injection, and 74% of the 473 respondents
reported at least one wrong-dose injection. 4 The
incorrect injections resulted in 1 death, 29 hospital
admissions, and 59 emergency department visits. In addition
to patient identifiers on vial labels, the authors cited
several reasons why this might reduce incorrect injection
errors. One reason was that patient-specific vials can be
prepared in a quiet laboratory setting, which might provide
substantially less distraction than the nurse in a room with
a patient who is trying to concentrate only on drawing up
the injection correctly. In addition, the specific components
are mixed once with the preparation of individually
prepared patient-labeled vials, whereas the mixing would
be repeated on every injection visit if the allergen extract is
withdrawn from different stock solutions, as it is in the
off-the-board method. For safety reasons and to avoid
cross-mixing of allergens removed from the manufacturer’s
extract, the mixing of antigens in the syringe (off
the board) is not recommended.
Some allergists/immunologists prefer to administer
immunotherapy doses drawn directly from a single stock
dilution of individual allergens or common mixes (shared
specific patient vials). In this way the immunotherapy dose
is transferred to the patient without cross-contamination. If
shared-patient (eg, mixed vespids and dust mite mix) vials
are used, it is essential that policies and procedures are
developed to verify that the correct dose from the correct
vial is administered to the correct patient.
Starting doses
Summary Statement 42: The starting dose for build-up
is usually a 1000- or 10,000-fold dilution of the maintenance
concentrate, although a lower starting dose might be
advisable for highly sensitive patients. D
There are 2 phases of allergen immunotherapy administration:
the initial build-up phase, when the dose and
concentration of allergen immunotherapy extract are
slowly increased, and the maintenance phase, when the
patient receives an effective therapeutic dose over a period
of time. If the starting dose is too dilute, an unnecessarily
large number of injections will be needed, resulting in a
delay in achieving a therapeutically effective dose. On the
other hand, if the starting dose is too concentrated, the
patient might be at increased risk of having a systemic
reaction.
When choosing the starting dose, most allergists/immunologists
start at a dilution of the maintenance concentrate
that is appropriate based on the sensitivity of the
patient to the allergens in the extract, which in turn is based
on the history and skin test reactivity.
Common starting dilutions from the maintenance concentrate
are 1:10,000 (vol/vol) or 1:1000 (vol/vol), although
more diluted concentrations frequently are used for
patients who are highly sensitive, as indicated by history
or skin test reaction (see Appendix 3 for an example of a
conventional immunotherapy schedule).
Frequency of build-up injections
Summary Statement 43: The frequency of allergen
immunotherapy administration during the build-up phase
is usually 1 to 2 injections per week. D
A number of schedules are used for the build-up phase
of immunotherapy. The most commonly used schedule is
for increasing doses of allergen immunotherapy extract to
be administered 1 to 2 times per week. This weekly
schedule is recommended in most of the allergen extract
package inserts. With this schedule, a typical patient can
expect to reach a maintenance dose in 4 to 6 months,
depending on the starting dilution and the occurrence of
reactions. It is acceptable for patients to receive injections
more frequently, provided there is adequate spacing
between injections. The interval between injections is
empiric but might be as short as 1 day without any increase
in the occurrence of systemic reactions 262 if there is some
urgency to achieve a maintenance dose (eg, allergy season
is approaching) or for practical reasons (eg, patient’s
schedule). Alternatively, treatment schedules can be
used that more rapidly achieve maintenance dosing.
These cluster and rush dosing schedules are discussed in
Summary Statements 47 through 49.
Allergen immunotherapy extracts used during the
build-up phase usually consist of three or four 10-fold
dilutions of the maintenance concentrate. The volume
generally is increased at a rate that depends on a number
of factors, including (1) the patient’s sensitivity to the