What treatment should be administered to a 66-year-old female experiencing an allergic reaction to an antibiotic?

From the Guidelines

For a 66-year-old female with an antibiotic allergic reaction, immediate assessment of severity is crucial, and treatment should be based on the severity of the reaction, with the most recent and highest quality study 1 guiding the approach to suspected antibiotic allergy.

Assessment and Treatment

For mild reactions (rash, itching), discontinue the antibiotic and administer diphenhydramine (Benadryl) 25-50 mg orally.

• For moderate reactions with hives or angioedema, add prednisone 40-60 mg orally.
• For severe reactions with respiratory distress or hypotension (anaphylaxis), immediately administer epinephrine 0.3-0.5 mg intramuscularly in the mid-outer thigh, call emergency services, place the patient in a recumbent position with legs elevated, provide oxygen, and establish IV access for fluid resuscitation.

Post-Stabilization Care

Monitor vital signs closely.

• After stabilization, document the allergic reaction in the patient's medical record,
• prescribe an epinephrine auto-injector for future use if anaphylaxis occurred,
• and refer to an allergist for further evaluation. The approach to suspected antibiotic allergy should consider the risk of recurrence of an allergic reaction upon re-exposure to the antibiotic or the risk of cross-allergy with other antibiotics, as outlined in the Dutch Working Party on Antibiotic Policy (SWAB) guideline 1.

Key Considerations

Allergic reactions occur when the immune system identifies an antibiotic as foreign, triggering histamine release and other inflammatory mediators that cause symptoms ranging from mild rash to life-threatening anaphylaxis.

• Prompt recognition and appropriate treatment based on severity are essential to prevent progression and complications.
• The guideline provides recommendations for the approach to suspected allergy to beta-lactam antibiotics (BLA) as well as frequently used non-beta-lactam antibiotics (NBLA), supporting antimicrobial stewardship 1.

Management of Antibiotic Allergy

The management of antibiotic allergy involves avoiding the culprit antibiotic and potentially other antibiotics within the same class, depending on the severity and type of reaction, as well as the time elapsed since the index reaction 1.

• A systematic approach to assessing the risk of recurrence and cross-reactivity is crucial in determining the safest course of action for patients with suspected antibiotic allergy.

From the FDA Drug Label

For the treatment of anaphylaxis, consider starting with a lower dose to take into account potential concomitant disease or other drug therapy. Diphenhydramine hydrochloride in the injectable form is effective in adults and pediatric patients, other than premature infants and neonates, for the following conditions when diphenhydramine hydrochloride in the oral form is impractical Antihistaminic For amelioration of allergic reactions to blood or plasma, in anaphylaxis as an adjunct to epinephrine and other standard measures after the acute symptoms have been controlled, and for other uncomplicated allergic conditions of the immediate type when oral therapy is impossible or contraindicated.

The patient should be given epinephrine (IM) as the first line of treatment for anaphylaxis, considering a lower dose due to the patient's age (66 years old) and potential concomitant disease or other drug therapy 2.

• Diphenhydramine (IV) can be used as an adjunct to epinephrine and other standard measures after the acute symptoms have been controlled 3.
• The treatment should be tailored to the patient's specific needs and medical history.

From the Research

Immediate Treatment for Anaphylaxis

• The first-line treatment for anaphylaxis is intramuscular epinephrine 4, which should be administered immediately in the event of an anaphylactic reaction.
• According to the World Allergy Organization, epinephrine has no absolute contraindication in the treatment of anaphylaxis 4.
• Intravenous epinephrine may be used in patients who are in shock, either as a bolus or infusion, along with fluid resuscitation 5.

Supportive Care

• Supportive care for the patient's airway, breathing, and circulation is crucial in the management of anaphylaxis 6, 5.
• Airway obstruction must be recognized, and early intubation may be necessary 5.
• Patients should be monitored for a biphasic reaction, which can occur within 4 to 12 hours after the initial reaction 6.

Adjunct Medications

• After epinephrine administration, adjunct medications such as histamine H1 and H2 antagonists, corticosteroids, beta2 agonists, and glucagon may be considered 6.
• However, the use of corticosteroids in anaphylaxis should be revisited, as recent studies suggest that they may not be beneficial and may even increase the risk of hospital admission 7.
• Antihistamines may have a beneficial effect in the management of anaphylaxis, particularly when used in conjunction with epinephrine 7.

Disposition and Follow-up

• Disposition depends on patient presentation and response to treatment 5.
• Patients should be monitored for a period of time after the reaction to ensure that they do not experience a biphasic reaction 6.
• Following an anaphylactic reaction, management should focus on developing an emergency action plan, referral to an allergist, and patient education on avoidance of triggers and appropriate use of an epinephrine auto-injector 6.