Recruiting

Phase 3

Penicillin AllergyPenicillin Allergy Delabeling After a One-Dose Versus Two-Dose Graded Direct Oral Challenge

Sponsor:

James Tarbox, MD

Code:

NCT06303128

Conditions

Penicillin Allergy

Eligibility Criteria

Sex: All

Age: 18 - 70+

Healthy Volunteers: Not accepted

Interventions

Amoxicillin 250 MG

Placebo

Amoxicillin 62.5mg

Amoxicillin 187.5mg

Study Details

Brief summary:

The goal of this clinical trial is to learn about dosing when testing to see if a penicillin allergy label can be removed from adults that had been labeled as "penicillin-allergic" previously. The main question it aims to answer is:

- In penicillin-allergic patients that are at low risk of having an allergic reaction, is a one-dose oral challenge with amoxicillin (a penicillin-based antibiotic) as safe and effective as a two-dose oral challenge?

Participants will, after being identified as having a low-risk penicillin allergy, be administered oral amoxicillin in a controlled setting and then monitored for an allergic reaction. Researchers will compare participants that took one dose of amoxicillin to participants that took two doses of amoxicillin (a small dose and then a larger dose) to see if either group was more likely to develop an allergic reaction.

Conditions

Penicillin Allergy

Study ID

NCT06303128

Start date

Feb 3, 2024

Status verified date

Apr, 2025

Completion date

Dec, 2026

Anticipated

Primary completion date

Jul, 2026

Anticipated

Eligibility Criteria

Sex: All

Age: 18 - 70+

Healthy Volunteers: Not accepted

Inclusion Criteria:

Expresses interest in participating by calling or filling out information form on study website
Reports an allergy to one of the following medications: penicillin VK, penicillin G, amoxicillin, ampicillin, dicloxacillin, flucloxacillin, nafcillin, oxacillin, amoxicillin- clavulanate, ampicillin-sulbactam. Subjects with an unspecified penicillin allergy are also eligible to participate.

Exclusion Criteria:

Penicillin allergy deemed to be more than "low-risk" per PEN-FAST (score ≥ 3 points)
History of acute kidney injury (acute interstitial nephritis), severe liver impairment (drug- induced liver injury), serum sickness, or isolated drug fever attributed to a penicillin- based antibiotic
Anaphylaxis for any reason in the last year
Cognitive impairment where a collateral history could not be obtained and/or patient does not have capacity to consent for themselves
Pregnant (self-reported)
Any illness or condition that would increase the risk of participation in the study, per the evaluating clinician's judgment
Active treatment of or history of acute angle closure glaucoma
On H1- or H2-blockers (i.e. diphenhydramine, hydroxyzine, chlorpheniramine, cetirizine, levocetirizine, loratadine, fexofenadine or famotidine, ranitidine, cimetidine, nizatidine, respectively) within 72 hours of initiating direct oral challenge (will be counseled to discontinue prior to testing)
Actively receiving greater than stress dose steroid (hydrocortisone >50mg four times a day or steroid equivalent)
Actively receiving any antibiotic
Relative contraindication: Patients on beta blockers and angiotensin converting enzyme inhibitors (ACE inhibitors) will have an open dialog with the study team regarding the risks and benefits of testing a low-risk penicillin allergy patient. A joint decision will be made based on the patient's preference and the physician's comfort level.

Study Design

Enrollment

380 participants

Anticipated

Allocation

Randomized

Intervention Model

Parallel Assignment

Primary purpose

Diagnostic

Interventions and Outcome Measures

Arms

experimental: One-dose group

Patients assigned to this group will receive a liquid placebo followed by full-dose liquid amoxicillin 250mg PO thirty minutes later.

active comparator: Graded, two-dose group

Patients assigned to this group will receive liquid amoxicillin (25% of 250mg dose), followed by liquid amoxicillin 187.5mg PO (75% of 250mg dose) thirty minutes later.

Interventions

Amoxicillin 250 MG

Liquid amoxicillin 250mg PO

Placebo

Given prior to amoxicillin 250mg in one-dose group

Amoxicillin 62.5mg

Given first in two-dose group, liquid amoxicillin 62.5mg PO

Amoxicillin 187.5mg

Given second in two-dose group, liquid amoxicillin 187.5mg PO

Primary outcome measure

Proportion of successfully "delabeled" subjects in one-dose versus two-dose groups [ Time Frame: 5 days (at time of first follow up phone call) ]

Central Contacts and Locations

Central contacts

Study Coordinator

806-543-8994 clinicalresearch@ttuhsc.edu

Joshua A Peterson, MD

josh.peterson.587@gmail.com

Locations

Texas Tech University Health Sciences Center

Recruiting

Lubbock, Texas, United States, 79430

Contacts

Study Coordinator

806-543-8994 clinicalresearch@ttuhsc.edu

Joshua A Peterson, MD

josh.peterson.587@gmail.com

Principal Investigator:

Jacob Nichols, MD

More Information

Sponsor

James Tarbox, MD

Last update posted

May 1, 2025

Last verified

Apr, 2025

Keywords

low-risk allergy
amoxicillin
drug allergy
direct oral challenge

Trial information was received from ClinicalTrials.gov and was last updated on 2026-09-10. This information was provided to ClinicalTrials.gov by James Tarbox, MD on 2025-05-01.