Bacteriostatic Water for Injection, USP is a sterile, non-pyrogenic, sterile water that contains 0.9% benzyl alcohol (9mg/mL) added as a bacteriostatic preservative. Bacteriostatic water can be used multiple times up to 28 days once opened. Pfizer recommends that after this time you must discard the vial.This preparation of sterile water and benzyl alcohol (BnOH) allows repeated withdrawals to be made from a single 30mL vial. Hospira Worldwide now Pfizer injectables is the world’s leading manufacturer of bacteriostatic water, Pfizer injectables recommends that once the vial of bacteriostatic water is open the preservatives will prolong its life for up to 28 days and that after this period of time the vial should to be discarded.
A bacteriostatic agent or bacteriostat is a biological or chemical agent that stops bacteria from reproducing, while not necessarily killing them otherwise. Depending on their application, bacteriostatic antibiotics, disinfectants, antiseptics and preservatives can be distinguished. When bacteriostatic antimicrobials are used, the duration of therapy must be sufficient to allow host defense mechanisms to eradicate the bacteria. Upon removal of the bacteriostat, the bacteria usually start to grow again. This is in contrast to bactericides, which kill bacteria.
How to Mix medications with Bacteriostatic water:
- Using an alcohol pad, wipe the rubber stopper on the first vial to decrease the risk of contaminating the medication as you insert the needle into the vial.
- Pull back syringe plunger until the volume of air drawn into the syringe equals the volume to be withdrawn from the drug vial.
- Without inverting the vial, insert the needle into the top of the vial, making sure that the needle’s bevel tip doesn’t touch the solution. Inject the air into the vial and withdraw the needle. This step replaces air in the vial, thus preventing the creation of a partial vacuum on the withdrawal of the drug.
- With a new needle, repeat the step above for the second vial or empty mixing vial. Then, after injecting the air into the second vial, invert the vial, withdraw the prescribed dose, and then withdraw the needle