Does Bacteriostatic Water Need to Be Refrigerated? Label Facts and Shelf Life
What the US label says about storing bacteriostatic water, how long it lasts unopened and opened, what is in it, and why it is not for newborns.
Update History ▾
Research-use-only framing applied throughout in line with Remy editorial standards.
Does bacteriostatic water need to be refrigerated? Not according to its label. The US label for Bacteriostatic Water for Injection, USP gives one storage condition: store at 20 to 25°C (68 to 77°F), USP controlled room temperature.[1] Other bacteriostatic water labels on file with FDA that state a storage condition list the same range, and none states a discard period after first opening.[2]
Shelf life has two parts. An unopened vial runs to the manufacturer’s expiry date printed on the label. For an opened multi-dose vial, CDC’s injection-safety rule is to date it and discard it within 28 days unless the manufacturer states another date, and never past the original expiry.[1][3] Bacteriostatic water is not for use in newborns because of its benzyl alcohol preservative.[1]
What Is Bacteriostatic Water?
Bacteriostatic Water for Injection, USP is a sterile, nonpyrogenic preparation of water for injection containing 0.9% (9 mg/mL) or 1.1% (11 mg/mL) benzyl alcohol, added as a bacteriostatic preservative. Its pH is 5.7, within a range of 4.5 to 7.0. Water for injection is chemically designated H2O.[1]
It is supplied in a multiple-dose container, for multi-dose use, from which repeated withdrawals may be made. The label describes it as a parenteral preparation designed only for diluting or dissolving drugs that need an aqueous vehicle prior to injection, not as a medicine in its own right.[1] In the Hospira presentation, the 30 mL vial carries 0.9% benzyl alcohol added and the 20 mL glass vial carries 1.1%.[1]
The label’s clinical pharmacology section is about water itself. Water is an essential constituent of all body tissues and accounts for about 70% of total body weight; the average normal adult daily requirement is two to three liters. Water balance is maintained by various regulatory mechanisms, and water distribution depends primarily on the concentration of electrolytes in the body compartments, with sodium playing a major role in maintaining physiologic equilibrium. The small volume used for diluting or dissolving drugs is unlikely to affect fluid balance except possibly in very small infants.[1]
Does Bacteriostatic Water Need to Be Refrigerated? How the Label Says to Store Bacteriostatic Water
The storage line on the Hospira label reads: store at 20 to 25°C (68 to 77°F), with a reference to USP controlled room temperature.[1] The label contains no refrigeration instruction and no separate condition for an opened vial.[1] Across the four bacteriostatic water labels returned by an openFDA search in October 2026, every label that states a storage condition gives the same 20 to 25°C range.[2]
| Label item | Bacteriostatic water | Source |
|---|---|---|
| Storage temperature | 20 to 25°C (68 to 77°F) | FDA label |
| Refrigeration | Not stated on the label | FDA label |
| Container type | Multiple-dose vial | FDA label |
| Unopened shelf life | Manufacturer’s expiry date | Label and CDC |
| Opened vial | Discard within 28 days unless the maker states otherwise | CDC guidance |
The label’s precautions also say the solution should be clear and the seal intact.[1]
Bacteriostatic Water Shelf Life: Unopened and Opened Vials
Unopened Vials
The vial label carries a lot number and an expiry date.[1] CDC states that an unopened multi-dose vial should be discarded according to the manufacturer’s expiration date.[3]
Opened Multi-Dose Vials and the 28-Day Rule
Once a multi-dose vial is opened, for example needle-punctured, CDC says it should be dated and discarded within 28 days unless the manufacturer states another date for that opened vial. The beyond-use date should never exceed the original expiration date, and any vial should be discarded whenever sterility is compromised or questionable.[3] The 28-day figure therefore comes from CDC injection-safety guidance, not from the bacteriostatic water labels reviewed here.[2]
Why Benzyl Alcohol Matters: The Neonate Warning
Every Hospira vial and tray reads “Not for use in neonates.” Under its warnings, benzyl alcohol is named as the preservative associated with toxicity in neonates; data on other preservatives in this age group are unavailable, and where water is required for preparing or diluting medications for use in neonates, only preservative-free sterile water for injection should be used.[1]
The warning goes back to 1982. CDC reported 16 deaths in pre-term infants at two hospitals whose catheters were flushed with bacteriostatic saline containing 9 mg/mL benzyl alcohol; the illness included metabolic acidosis, respiratory distress and gasping respirations. FDA then recommended that flush solutions containing benzyl alcohol not be used for newborns.[4] The same year, a report in the New England Journal of Medicine named it the gasping syndrome of benzyl alcohol poisoning.[5]
Other Warnings and Adverse Reaction Statements on the Label
- Contraindications. Because of the potential toxicity of benzyl alcohol in neonates, solutions containing it must not be used in this patient population; parenteral preparations with benzyl alcohol should not be used for fluid replacement or in epidural or spinal anesthesia procedures; the water must be made approximately isotonic prior to use.[1]
- Hemolysis. The label warns that intravenous administration without a solute may result in hemolysis.[1]
- Drug interactions. Some drugs may be incompatible in a given vehicle, when combined in the same vehicle, or in a vehicle containing benzyl alcohol.[1]
- Pediatric use. Safety and effectiveness have not been established in pediatric patients.[1]
- Pregnancy. Animal reproduction studies have not been conducted, and it is not known whether Bacteriostatic Water for Injection, USP containing additives can cause fetal harm or affect reproduction capacity.[1]
- Adverse reactions. Reactions linked to the solution, added drugs or technique include febrile response, local tenderness, abscess, tissue necrosis or infection at the site, venous thrombosis or phlebitis, and extravasation. The label adds that adverse reactions to small volume parenteral preparations of 0.9% benzyl alcohol are not known to occur in humans, but large amounts are potentially capable of producing blood pressure changes in very small infants.[1]
- Fluid overload. Used only as a diluent or solvent, it is unlikely to cause fluid overload except possibly in very small infants.[1]
Bacteriostatic Water vs Sterile Water for Injection
Sterile Water for Injection, USP is also sterile and nonpyrogenic, but it contains no bacteriostat, antimicrobial agent or added buffer. It is supplied only in single-dose containers, its label says to discard the unused portion, and it is stored at the same 20 to 25°C.[6] Bacteriostatic water differs by its benzyl alcohol and its multiple-dose container.[1] For a fuller comparison, see bacteriostatic water vs sterile water.
The Container: Semi-Rigid Vial and Labeled Volume
The Hospira 30 mL vial is a semi-rigid vial fabricated from a specially formulated polyolefin, a copolymer of ethylene and propylene. Its safety was confirmed by tests in animals under USP biological standards for plastic containers, and the container requires no vapor barrier to maintain the proper labeled volume.[1]
Bacteriostatic Water for Laboratory Research
Remy Research supplies bacteriostatic water for in-vitro laboratory research as the Bacteriostatic Water 3ml vial, the ZPHC BAC Water 11mL vial, the ZPHC BAC Water 40mL vial and the ZPHC Bacteriostatic Water with Acetic Acid 11mL vial. Each product page carries its batch testing details. For broader context on research compound handling, see the bacteriostatic water guide and the peptide stability and storage guide.
Our Research Standards
This article is built from current FDA-listed product labels, CDC guidance and primary reports, and presents label statements as label facts. It gives no reconstitution, mixing, dosing or administration instructions. Read our editorial policy →
Bacteriostatic Water Refrigeration and Shelf Life FAQ
Does bacteriostatic water need to be refrigerated?
Its US label does not call for refrigeration. The stated storage condition is 20 to 25°C (68 to 77°F), USP controlled room temperature.[1]
How long does bacteriostatic water last after opening?
CDC guidance is to date an opened multi-dose vial and discard it within 28 days unless the manufacturer states another date, and never past the original expiry.[3]
What is the shelf life of unopened bacteriostatic water?
What is in bacteriostatic water?
Sterile, nonpyrogenic water for injection with 0.9% or 1.1% benzyl alcohol as a bacteriostatic preservative, pH 5.7.[1]
Is bacteriostatic water the same as sterile water?
Why is bacteriostatic water not for newborns?
What are the side effects of bacteriostatic water?
The label lists reactions from the solution, added drugs or technique, such as febrile response, local tenderness, abscess, infection, phlebitis and extravasation, and hemolysis if given intravenously without a solute.[1]
Is bacteriostatic water FDA approved?
The Hospira Bacteriostatic Water for Injection, USP is a prescription product listed on DailyMed with the marketing status New Drug Application.[1]
Sources
- Bacteriostatic Water for Injection, USP (Hospira, Inc.), prescribing information on DailyMed, set id 87d6e9dc-fe3b-4593-ac9a-d7493d1959c7, updated May 22, 2026, checked October 28, 2026. dailymed.nlm.nih.gov ↩
- openFDA drug label search for generic name “bacteriostatic water”, run October 28, 2026 (4 labels from Hospira and three other labelers; all list storage at 20 to 25°C where storage is stated, and none states a discard period after first opening). api.fda.gov ↩
- Centers for Disease Control and Prevention. Preventing Unsafe Injection Practices: key points for multi-dose vials (last reviewed March 26, 2024), checked October 28, 2026. cdc.gov ↩
- Centers for Disease Control and Prevention. Neonatal deaths associated with use of benzyl alcohol — United States. MMWR Morb Mortal Wkly Rep. 1982;31(22):290-291. PMID 6810084. cdc.gov/mmwr ↩
- Gershanik J, Boecler B, Ensley H, et al. The gasping syndrome and benzyl alcohol poisoning. N Engl J Med. 1982;307(22):1384-1388. doi: 10.1056/NEJM198211253072206 · PMID: 7133084 ↩
- Sterile Water for Injection, USP (Hospira, Inc.), prescribing information on DailyMed, set id 2b9ea23a-f9e9-48a8-25b7-519e3bbd6828, revised March 2026, checked October 28, 2026. dailymed.nlm.nih.gov ↩
For catalog details, see the Bacteriostatic Water 3ml vial, the ZPHC BAC Water 11mL vial, the ZPHC BAC Water 40mL vial and the ZPHC Bacteriostatic Water with Acetic Acid 11mL vial. For editorial standards, continue to the editorial policy.