Hilma Bacteriostatic water

Bacteriostatic water is prepared to inhibit the growth of most bacterial types. It consists of sterile and filtered water, from which all bacteria have been eliminated, and is mixed with 0.9% benzyl alcohol to prevent the growth of any contaminating bacteria, thereby keeping the bacterial content relatively stable.

This type of water is used to dilute or dissolve medications for injections. Unlike sterile water, which is purified but contains no additives and is typically for single use only, bacteriostatic water can be reused.

One may wonder why bacteriostatic water does not include an agent that outright kills bacteria. While it does not contain a bactericidal agent like some injection fluids, it effectively inhibits bacterial growth. Antibacterial agents can sometimes cause adverse reactions with medications, but benzyl alcohol does not. Thus, bacteriostatic water can be used for a wider range of drug dilutions or injections without negatively interacting with agents that kill bacteria.

Although both sterile and bacteriostatic water are free of bacteria initially, they can become contaminated after their first use (typically through syringe insertion). This is why sterile water is designated for single use only. In contrast, the advantage of bacteriostatic water is that the bacteria that may contaminate it cannot grow and multiply, allowing for multiple uses.

Most manufacturers of bacteriostatic water advise discarding any unused portion after 28 days, as the efficacy of the benzyl alcohol in preventing bacterial growth may diminish over time.

In some cases, bacteriostatic water is formulated to inhibit bacterial growth using a salt solution rather than benzyl alcohol, depending on the specific application.

Bacteriostatic water can be administered in three primary ways: The choice of method depends on the specific medication and the optimal delivery route as determined by a medical professional.