What is commonly found in multi-dose vials that can act as an allergen?

Methylparaben is a commonly used preservative in multi-dose vials that can act as an allergen for some individuals. It helps to prevent the growth of bacteria and fungi in the vial, ensuring the longevity and safety of the medication. However, due to its structure, some people may develop allergic reactions to methylparaben, which can manifest as skin irritations or more systemic allergic responses.

While other substances listed can also have potential side effects or sensitivities, methylparaben is particularly noted for its allergenic properties. It is important for healthcare providers to be aware of such preservatives when prescribing or administering medications, as patients may have specific allergies that could lead to adverse reactions.