Open AccessNonirritant concentrations and amount of active ingredient in drug patch tests optimal concentrations for DPTs
Author(s) -
Brajon Delphine,
Menetre Sophie,
Waton Julie,
Poreaux Claire,
Barbaud Annick
Publication year - 2014
Publication title -
clinical and translational allergy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.979
H-Index - 37
ISSN - 2045-7022
DOI - 10.1186/2045-7022-4-s3-p1
Subject(s) - medicine , drug , active ingredient , digoxin , pharmacology , heart failure
Background Drug patch tests (DPTs) with medications suspected of causing an allergic reaction represent a method of diagnostic testing that is low risk, as DPTs can reproduce delayed hypersensitivity to drugs and entail only a moderate re-exposure of patients to potential offending drugs. We assessed the non-irritating concentration of DPTs to determine the amount of active ingredient (AI) contained in the drugs used in the tests. Method From a retrospective, single-center study of all patients treated during a 6-year period for etiological investigations following a drug eruption, each potentially responsible drug was tested from the commercially available preparation diluted to 30% of its concentration in water, petrolatum, or alcohol. Data collection was performed with a customized computer database. For each type of DPT studied, the numbers of positive and negative tests were recorded. The amount of AI contained in the DPT (as a percentage) was then calculated after weighing each tablet. Results Of the 5,558 DPTs studied, all were nonirritant. The average concentration of AI was 9.8%; 25% of DPTs had an AI concentration less than 2%, and 25% displayed an AI concentration above 16%. The AI concentration ranged from 0.05% (digoxin) to 30% (paracetamol lyophilisate). Discussion The actual concentrations of the AI in DPTs done at 30% of the commercially available form varied from