Overview
DESCRIPTION: PRE-PEN ® (benzylpenicilloyl polylysine) injection is a sterile solution of benzylpenicilloyl polylysine in a concentration of 6.0 X 10 -5 M (benzylpenicilloyl) in 0.01 M monobasic sodium phosphate and 0.15 M sodium chloride. Benzylpenicilloyl polylysine is a derivative of poly-l-lysine, where the epsilon amino groups are substituted with benzylpenicilloyl groups (50-70%) forming...
Mechanism of Action
CLINICAL PHARMACOLOGY: PRE-PEN is a skin test antigen reagent that reacts specifically with benzylpenicilloyl IgE antibodies initiating the release of chemical mediators which produce an immediate wheal and flare reaction at a skin test site. All individuals exhibiting a positive skin test to PRE-PEN possess IgE against the benzylpenicilloyl structural group which is a hapten. A hapten is a low molecular weight chemical that conjugates with a carrier (e.g. poly-l-lysine) resulting in the formation of an antigen with the hapten’s specificity. The benzylpenicilloyl hapten is the major antigenic determinant in penicillin-allergic individuals.
Indications
- INDICATIONS AND USAGE: PRE-PEN 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 PRE-PEN 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 PRE-PEN. These allergic reactions are predominantly dermatologic.
Common Doses
- Refer to label
Dosage
DOSAGE AND ADMINISTRATION: SKIN TESTING DOSAGE AND TECHNIQUE Skin testing responses can be attenuated by interfering drugs (e.g. H1-antihistamines 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.
Contraindications
- CONTRAINDICATIONS: PRE-PEN 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.
Side Effects
- ADVERSE REACTIONS: Occasionally, patients may develop an intense local inflammatory response at the skin test site. Rarely, patients will develop a systemic allergic reaction, manifested by generalized erythema, pruritus, angioedema, urticaria, dyspnea, hypotension, and anaphylaxis. The usual methods of treating a skin test antigen-induced reaction — the applications of a venous occlusion tourniquet proximal to the skin test site and administration of epinephrine are recommended. The patient should be kept under observation for several hours.
Interactions
- No major interactions listed on the FDA label. Always consult a healthcare professional.