Contact allergens in oral antihistamines

Area of Science:

• Dermatology
• Pharmacology
• Allergology

Background:

• Medications, including oral antihistamines, can contain excipients that are known contact allergens.
• Ingestion of these allergens can lead to dermatitis, which may become widespread or resistant to treatment.

Purpose of the Study:

• To determine the frequency of common contact allergens within the excipients of oral antihistamines available in the country.
• To identify specific antihistamine formulations and excipients associated with a higher risk of allergic reactions.

Main Methods:

• Ingredient lists of 2119 oral antihistamine preparations from 12 different drugs were collected from the National Library of Medicine.
• Data were entered into an electronic database for comprehensive analysis of excipient content.

Main Results:

• Over half (55.0%) of the antihistamine formulations contained at least one of the ten assessed allergen families.
• Brompheniramine and doxepin preparations frequently included allergenic excipients, while fexofenadine formulations were least likely to contain them.
• Sorbitan group members, azo dyes, and propylene glycol were the most common allergens, found in over 25% of products. Liquid formulations (elixirs, syrups, etc.) were more likely to contain allergens than solid dosage forms.

Conclusions:

• Oral antihistamine use can trigger systemic contact dermatitis in sensitized individuals due to allergenic excipients.
• Awareness of these allergens in medication formulations is crucial for managing and preventing allergic skin reactions.