Do parenteral drugs always contain preservatives?

Parenteral drugs, which are administered by injection, do not necessarily require the inclusion of preservatives. The primary purpose of preservatives is to prevent microbial growth in multi-dose vials once opened. While many parenteral formulations do contain preservatives to ensure safety and stability, there are exceptions where preservatives are intentionally excluded, especially in single-dose vials. The decision to include a preservative often depends on the drug's formulation, intended use, and the routes of administration.

This flexibility is essential because certain populations, such as infants or immunocompromised patients, may have heightened sensitivity to preservatives. Additionally, for some specific drugs, particularly biologics or certain sterile preparations, the inclusion of preservatives may not be compatible with the drug's formulation or may affect its efficacy. Thus, it is important to recognize that the presence of preservatives in parenteral medications is not mandatory, confirming that the assertion that parenteral drugs always contain preservatives is inaccurate.