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Overview
Benzylpenicilloyl Polylysine is a Diagnostic Agent that is FDA approved for the diagnosis of sensitization to penicillin (benzylpenicillin or penicillin G) in patients suspected to have clinical penicillin hypersensitivity. Common adverse reactions include allergic reaction, local inflammatory response.
Adult Indications and Dosage
FDA-Labeled Indications and Dosage (Adult)
Indications
PREPEN is indicated for the assessment of sensitization to penicillin (benzylpenicillin or penicillin G) in patients suspected to have clinical penicillin hypersensitivity. A negative skin test to PREPEN is associated with an incidence of immediate allergic reactions of less than 5% after the administration of therapeutic penicillin, whereas the incidence may be more than 50% in a history-positive patient with a positive skin test to PREPEN. These allergic reactions are predominantly dermatologic. Whether a negative skin test to PREPEN predicts a lower risk of anaphylaxis is not established. Similarly, when deciding the risk of proposed penicillin treatment, there are not enough data at present to permit relative weighing in individual cases of a history of clinical penicillin hypersensitivity as compared to positive skin tests to PREPEN and/or minor penicillin determinants.
Dosage
SKIN TESTING DOSAGE AND TECHNIQUE
Skin testing responses can be attenuated by interfering drugs (e.g. H1antihistamines and vasopressors). Skin testing should be delayed until the effects of such drugs have dissipated, or a separate skin test with histamine can be used to evaluate persistent antihistaminic effects in vivo. Due to the risk of potential systemic allergic reactions, skin testing should be performed in an appropriate healthcare setting under direct medical supervision.
Puncture Testing:
Skin testing is usually performed on the inner volar aspect of the forearm. The skin test antigen should always be applied first by the puncture technique. After preparing the skin surface, apply a small drop of PREPEN solution using a sterile 2228 gauge needle. The same needle can then be used to make a single shallow puncture of the epidermis through the drop of PREPEN. Very little pressure is required to break the epidermal continuity. Observe for the appearance of a wheal, erythema, and the occurrence of itching at the test site during the succeeding 15 minutes at which time the solution over the puncture site is wiped off. A positive reaction consists of the development within 10 minutes of a pale wheal, sometimes with pseudopods, surrounding the puncture site and varying in diameter from 5 to 15 mm (or more). This wheal may be surrounded by a variable diameter of erythema, and accompanied by a variable degree of itching. The most sensitive individuals develop itching quickly, and the wheal and erythema are prompt in their appearance. As soon as a positive response as defined above is clearly evident, the solution over the scratch should be immediately wiped off. If the puncture test is either negative or equivocally positive (less than 5 mm wheal with little or no erythema and no itching), an intradermal test may be performed.
The lntradermal Test:
Using a 0.5 to 1.0 cc syringe with a 3/8” to 5/8”long, 26 to 30 gauge, short bevel needle, withdraw the contents of the ampule. Prepare with an alcohol swab a skin test area on the upper, outer arm, sufficiently below the deltoid muscle to permit proximal application of a tourniquet later, if necessary. Be sure to eject all air from the syringe through the needle, then insert the needle, bevel up immediately below the skin surface. Inject an amount of PREPEN sufficient to raise a small intradermal bleb of about 3 mm in diameter, in duplicate at least 2 cm apart. Using a separate syringe and needle, inject a like amount of saline or allergen diluting solution as a control at least 5 cm removed from the antigen test sites. Most skin reactions will develop within 5-15 minutes and response to the skin test is read at 20 minutes as follows:
Negative response — no increase in size of original bleb and no greater reaction than the control site.
Ambiguous response — wheal only slightly larger than initial injection bleb, with or without accompanying erythematous flare and slightly larger than the control site; OR discordance between duplicates.
Positive response — itching and significant increase in size of original blebs to at least 5 mm. Wheal may exceed 20 mm in diameter and exhibit pseudopods.
If the control site exhibits a wheal greater than 23 mm, repeat the test, and if the same reaction is observed, a physician experienced with allergy skin testing should be consulted.
Off-Label Use and Dosage (Adult)
Guideline-Supported Use
There is limited information regarding Off-Label Guideline-Supported Use of Benzylpenicilloyl Polylysine in adult patients.
Non–Guideline-Supported Use
There is limited information regarding Off-Label Non–Guideline-Supported Use of Benzylpenicilloyl Polylysine in adult patients.
Pediatric Indications and Dosage
FDA-Labeled Indications and Dosage (Pediatric)
There is limited information regarding FDA-Labeled Use of Benzylpenicilloyl Polylysine in pediatric patients.
Off-Label Use and Dosage (Pediatric)
Guideline-Supported Use
There is limited information regarding Off-Label Guideline-Supported Use of Benzylpenicilloyl Polylysine in pediatric patients.
Non–Guideline-Supported Use
There is limited information regarding Off-Label Non–Guideline-Supported Use of Benzylpenicilloyl Polylysine in pediatric patients.
Contraindications
PREPEN is contraindicated in those patients who have exhibited either a systemic or marked local reaction to its previous administration. Patients known to be extremely hypersensitive to penicillin should not be skin tested.
Warnings
The risk of sensitization to repeated skin testing with PREPEN is not established. Rarely, a systemic allergic reaction including anaphylaxis (see below) may follow a skin test with PREPEN. To decrease the risk of a systemic allergic reaction, puncture skin testing should be performed first. Intradermal skin testing should be performed only if the puncture test is entirely negative.
Precautions
General
No reagent, test, or combination of tests will completely assure that a reaction to penicillin therapy will not occur.
The value of the PREPEN skin test alone as a means of assessing the risk of administering therapeutic penicillin (when penicillin is the preferred drug of choice) in the following situations is not established:
Adult patients who give no history of clinical penicillin hypersensitivity.
Pediatric patients.
In addition, the clinical value of PREPEN where exposure to penicillin is suspected as a cause of a current drug reaction or in patients who are undergoing routine allergy evaluation is not known. Likewise, the clinical value of PREPEN skin tests alone in determining the risk of administering semi-synthetic penicillins (phenoxymethyl penicillin, ampicillin, carbenicillin, dicloxacillin, methicillin, nafcillin, oxacillin, amoxicillin), cephalosporin-derived antibiotics, and penem antibiotics is not known.
In addition to the results of the PREPEN skin test, the decision to administer or not administer penicillin should take into account individual patient factors. Healthcare professionals should keep in mind the following:
A serious allergic reaction to therapeutic penicillin may occur in a patient with a negative skin test to PREPEN.
It is possible for a patient to have an anaphylactic reaction to therapeutic penicillin in the presence of a negative PREPEN skin test and a negative history of clinical penicillin hypersensitivity.
If penicillin is the drug of choice for a life-threatening infection, successful desensitization with therapeutic penicillin may be possible irrespective of a positive skin test and/or a positive history of clinical penicillin hypersensitivity.
Adverse Reactions
Clinical Trials Experience
There is limited information regarding Clinical Trial Experience of Benzylpenicilloyl Polylysine in the drug label.
Body as a Whole
Cardiovascular
Digestive
Endocrine
Hematologic and Lymphatic
Metabolic and Nutritional
Musculoskeletal
Neurologic
Respiratory
Skin and Hypersensitivy Reactions
Special Senses
Urogenital
Miscellaneous
Postmarketing Experience
There is limited information regarding Postmarketing Experience of Benzylpenicilloyl Polylysine in the drug label.
Animal reproduction studies have not been conducted with PREPEN. It is not known whether PREPEN can cause fetal harm when administered to a pregnant woman or can affect reproduction capacity. The hazards of skin testing in such patients should be weighed against the hazard of penicillin therapy without skin testing.
There is limited information regarding Patient Counseling Information of Benzylpenicilloyl Polylysine in the drug label.
Precautions with Alcohol
Alcohol-Benzylpenicilloyl Polylysine interaction has not been established. Talk to your doctor about the effects of taking alcohol with this medication.
