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Excipient Allergy

Meaning

Excipient allergy is a distinct form of adverse drug reaction where the body’s immune system mounts a hypersensitivity response to an inactive ingredient within a pharmaceutical or compounded product, rather than the active drug substance itself. Excipients are substances included for bulk, stability, taste, or dissolution, such as dyes, preservatives, or fillers like lactose or gluten. This type of allergy presents a clinical challenge, requiring careful formulation review and ingredient avoidance to ensure patient safety and therapeutic adherence. Recognizing this specific reaction is vital for effective personalized prescribing, especially in hormone replacement therapy.