What is the guide for Penicillin (antibiotic) desensitization?

From the Guidelines

Penicillin desensitization should be performed in a hospital setting, orally or IV, with continuous monitoring, as it is a relatively safe procedure that can be completed in approximately 4–12 hours, as stated in the 2010 guidelines 1. The process of desensitization typically involves administering gradually increasing doses of penicillin, starting with extremely small amounts, and doubling the dose every 15-30 minutes until the full therapeutic dose is reached.

• Key considerations for penicillin desensitization include:
  • The procedure should be performed under specialist supervision in a hospital setting due to the risk of serious IgE-mediated allergic reactions 1.
  • Patients must be maintained on penicillin continuously for the duration of the course of therapy after desensitization.
  • The desensitization effect is temporary, and if therapy is interrupted, the process may need to be repeated.
• According to the guidelines, oral desensitization is regarded as safer and easier to perform than IV desensitization 1. The decision to undergo penicillin desensitization should be made when penicillin is the most appropriate treatment option and no suitable alternatives exist, due to the risks associated with the procedure, including anaphylaxis.
• The benefits of penicillin desensitization, as outlined in the guidelines, include enabling patients with penicillin allergy to safely receive penicillin when necessary 1.

From the FDA Drug Label

The reported incidence of allergic reactions to all penicillins ranges from 0. 7 to 10 percent in different studies Two types of allergic reactions to penicillin are noted clinically – Immediate and delayed. Immediate reactions usually occur within 20 minutes of administration and range in severity from urticaria and pruritus to angloneurotic edema, laryngospasm, bronchospasm, hypotension, vascular collapse and death Delayed reactions to penicillin therapy usually occur within 1 to 2 weeks after initiation of therapy.

The FDA drug label does not provide a penicillin desensitization guide. However, it describes the types of allergic reactions that can occur with penicillin therapy, including immediate and delayed reactions.

• Immediate reactions can be severe and life-threatening, and may require emergency treatment.
• Delayed reactions can also be serious, and may include symptoms such as fever, malaise, and skin rashes. No specific guidance is provided on how to desensitize patients to penicillin 2.

From the Research

Penicillin De-sensitization Guide

• Penicillin de-sensitization is a procedure used to administer beta-lactam antibiotics to patients who are allergic to penicillin 3, 4.
• The procedure involves administering increasing doses of penicillin orally or intravenously, starting with a small dose and gradually increasing it over a period of time 3, 4.
• The goal of de-sensitization is to allow the patient to tolerate a full therapeutic dose of the antibiotic without experiencing an allergic reaction 3, 4.

Indications for De-sensitization

• De-sensitization is indicated for patients with a history of allergic reactions to penicillin who require treatment with a beta-lactam antibiotic for a life-threatening infection 3, 4.
• It is also indicated for patients with a positive skin test to penicillin who require treatment with a penicillin-type drug and for whom there is no alternative 5.

Methods of De-sensitization

• Oral de-sensitization involves administering increasing doses of penicillin orally, starting with a small dose and gradually increasing it over a period of time 3, 4.
• Intravenous de-sensitization involves administering increasing doses of penicillin intravenously, starting with a small dose and gradually increasing it over a period of time 3.

Safety and Efficacy

• De-sensitization is a relatively safe procedure, with a low risk of serious allergic reactions 3, 4.
• The efficacy of de-sensitization has been demonstrated in several studies, with a high success rate in allowing patients to tolerate a full therapeutic dose of the antibiotic without experiencing an allergic reaction 3, 4.

Alternative Approaches

• For patients with a low-risk history of penicillin allergy, a direct amoxicillin challenge may be appropriate 6.
• For patients with a moderate-risk history, penicillin skin testing may be used to evaluate the risk of an allergic reaction 6.
• For patients with a high-risk history, de-sensitization may be necessary to allow the patient to tolerate a full therapeutic dose of the antibiotic 6.