A Quick Guide to Bacteriostatic Water, Its Benefits, And Uses

A Simple Guide to Bacteriostatic Water


Bacteriostatic water (BW) is non-pyrogenic, sterile water stored in a multi-dose vial for diluting medications. It contains a bacteriostat -0.9% benzyl alcohol- which is an essential defense component against contamination by bacteria.

BW is mainly used as a diluent by medical practitioners for preparing solute-like drug substances, often in the powder state. Nowadays, patients also have some autonomy for self-medication especially diabetic patients. And that means there is a high possibility for misuse to occur outside the healthcare premises.

In this article, you will learn the uses of bacteriostatic water, the availability of Bacteriostatic water in Australia, precautions, and other necessary details to help you steer clear of misuse.

Benefits And Uses Of Bacteriostatic water

Bacteriostatic water is used for mixing drug solutes into injectable solutions. After preparation, the solution can be administered through intramuscular, intravenous, or subcutaneous routes.

Although there are other types of sterile water, BW is mostly used because of its important benefits, which include:

  1. It Serves As A Drug Diluent And Medium

Most drugs are produced in powder form to prolong their storage time. A drug diluent like bacteriostatic water is used to dissolve the solute particles and form a crystal clear, injectable solution.

Not just any liquid can be used as a diluent. There are some factors to consider, such as pH, purity level, and concentration of the bacteriostat added. Each of these requirements is strictly met during the production of BW to ensure the output of high-quality sterile water.

Bacteriostatic water also serves as a good transport medium. The pH of bacteriostatic water ranges between 4.5 – 7.0. This range is an essential baseline for the pharmacological action of drugs. pH of a diluent can affect the effectiveness and absorption rate of the medication you are preparing.

Bacteriostatic Water Is Anti-microbial

Bacteriostatic water is called so because of the presence of an antimicrobial compound, benzyl alcohol. The small 0.9% concentration of this bacteriostat makes it very suitable for use without any notable adverse reactions.

The multi-dose vial of bacteriostatic water can be accessed several times until the water is exhausted. Moreover, the presence of a bacteriostat ensures that bacteria do not grow or colonize the bottle until after 28 days.

It is important to know that the presence of microbial activity in drug solutions can lead to serious consequences, which can be life-threatening. Thus, BW is highly recommended as a diluent suitable for long time use and saves money for the user since you don’t always have to buy another sterile water after a one-time use.

Precautions For Using Bacteriostatic Water

While using BW is as simple as using injection needles to withdraw and mixing with the mymedic.es provided drug solute, there are still some things you need to know. (Check out uses and detailed background here).

  • Bacteriostatic water is not suitable for pediatric use since it can cross the placenta. Neonates generally react to the potential toxicity of benzyl alcohol.

Since the baseline for potential toxicity is not known, BW should only be used for less than a week in children under the age of two years. Unless absolutely necessary, pregnant women should only make use of ordinary sterile water.

  • Bacteriostatic water is not for oral consumtion and should only be used for intramuscular, intravenous, and subcutaneous injection. Oral use can lead to some undesirable gastrointestinal complications.
  • Unsealed bacteriostatic water vials at purchase should be rejected. Preferably, only get BW from reputable sites or standard pharmacies.
  • Patients hypersensitive to benzyl alcohol should report to their primary care physician before using bacteriostatic water.
  • Watch out for any visible reaction on-mix. Usually, bacteriostatic water does not react with drug solutes.
  • Directly injecting BW without mixing with a drug solute can result in hemolysis.

Side Effects Of Bacteriostatic Water

Bacteriostatic water is sterilized and naturally does not produce any undesired effects. However, the presence of particulate matter, which is most likely during production, can result in some unwanted complications.

In rare cases, some patients complain of:

  • Redness
  • Febrile response at the injection site
  • Rarely, tissue death.

Other side effects developed after injection should also be from the drug solute.

Bacteriostatic Water Or Pure Sterile Water: Which One is Better?

One important thing to note is that not all sterile water is bacteriostatic. Pure sterile water does not contain a bacteriostat like benzyl alcohol and can only be used once. Since it lacks an antimicrobial component, it has to be discarded after a one-time use.

However, sterile water has its own strength. There is no need to worry about potential benzyl alcohol toxicity or hypersensitivity.

Overall, bacteriostatic water is best for diluting drug solutes, especially in environments where the risk of contamination is increased. It is cost effective and can be used multiple times.

Where Can I Buy Bacteriostatic Water?

The internet has tons of reputable BW providers you can choose from. Most pharmacies also have bacteriostatic water for sale. Since this water does not have any other generic name or chemical alias, you don’t need to worry about the differences in location.

Can Bacteriostatic Water Be Produced At Home?

There are several DIYs for producing bacteriostatic water yourself. So the answer is yes.

However, there is a 99% risk of contamination. The production of bacteriostatic water emphasizes a standard sterility level, which can not be achieved with normal equipment. Certified companies producing BW already have these high-priced machines responsible for purifying the air and production materials inside the production room.

You will also unavoidably overlook some microscopic details that need to be recorded throughout the manufacturing process. That is why you should get it from a notable source instead of following how-to guides on the internet.


Choosing the right diluent is a very important decision to make in the healthcare industry.

Special care must be taken

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when addressing pediatric patients, and BW should only be used in unavoidable situations.

Although bacteriostatic water is antimicrobial in nature, medical practitioners must not neglect the role of precaution. Those practicing self-care must ensure they report any persistent or severe complications noticed to their primary care physician.