Comprehensive medication guide to Sterile Water for Injection including estimated pricing, availability information, side effects, and how to find it in stock at your local pharmacy.
Estimated Insurance Pricing
For patients on home infusion therapy, SWFI is typically covered under the bundled home infusion per-diem benefit — not billed as a standalone prescription. Medicare Part B covers it as part of qualifying home infusion services. Out-of-pocket cost for home infusion patients is generally $0 when billed correctly under the infusion benefit.
Estimated Cash Pricing
$1–$5 per single-dose vial (5–20 mL) at retail; case packs of 25 vials of 30 mL Bacteriostatic Water range from $148–$340 depending on brand and availability. Hospital and institutional pricing is lower through GPO contracts.
Medfinder Findability Score
35/100
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Sterile Water for Injection, USP (SWFI) is a sterile, nonpyrogenic, preservative-free pharmaceutical diluent. Chemically designated H₂O with a pH of 5.0–7.0, it is manufactured to strict FDA standards for sterility, freedom from pyrogens, and particulate matter limits. It is available only in single-dose containers ranging from 2 mL vials to 3,000 mL pharmacy bulk packages, and is labeled 'Rx only' in the United States.
SWFI has no pharmacological effect of its own. Its sole purpose is to dissolve or dilute powdered or concentrated injectable medications before they are administered to a patient. It is used across virtually every clinical specialty—from hospital ICUs to home infusion therapy—and is one of the most widely used pharmaceutical products in American healthcare.
Common medications reconstituted with SWFI include antibiotics (cefazolin, acyclovir, vancomycin), biologics, vaccines, growth hormone, oncology agents (alteplase), and many others. Despite being 'just water,' manufacturing SWFI to USP pharmaceutical standards requires specialized sterile production facilities, rigorous quality testing, and aseptic filling—making it a complex manufactured drug product.
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SWFI acts as a pharmaceutical solvent—a vehicle for delivering active drug molecules into the body. Many medications are manufactured as freeze-dried (lyophilized) powders because the drug is too unstable to store in liquid form. Adding SWFI to the vial dissolves the powder back into an injectable solution at the precise concentration needed for safe and effective administration.
The key pharmacological principle governing SWFI's use is osmolarity. Body fluids are maintained at approximately 285–295 mOsm/L (isotonic). Pure water has essentially zero osmolarity. If pure water is injected directly into a vein, red blood cells rapidly absorb water by osmosis and burst—a dangerous process called hemolysis. This is why SWFI carries the FDA label warning 'NOT ISOTONIC. HEMOLYTIC.' and must never be given alone.
When SWFI is combined with a drug powder or concentrated solution at the volumes specified in the drug's prescribing information, the dissolved drug molecules raise the osmolarity of the resulting solution to near-isotonic levels, making it safe for IV, IM, or subcutaneous injection. The water then acts purely as a carrier—it is absorbed and excreted normally while the drug exerts its therapeutic effects.
2 mL — single-dose vial
Smallest presentation; used for minimal-volume reconstitutions
5 mL — single-dose vial
Common vial size for small-volume drug reconstitution
10 mL — single-dose vial
Standard vial size widely used in hospitals for IV push drug reconstitution
20 mL — single-dose vial
Larger single-dose vial for medications requiring higher diluent volumes
30 mL — multi-dose vial (Bacteriostatic Water only)
Multi-dose format contains 0.9% benzyl alcohol; usable for 28 days after first entry
50 mL — single-dose vial
Used for medications requiring larger reconstitution volumes
100 mL — glass vial
Larger glass vial for compounding and batch preparation
1000 mL — IV bag / pharmacy bulk package
Hospital and institutional use; not for direct patient administration; used for batch preparation under USP <797> conditions
Finding Sterile Water for Injection is significantly harder than average in 2026. SWFI has been on the FDA's active drug shortage list since November 2021—making it one of the longest-running active pharmaceutical shortages in the U.S. market. The shortage stems from: (1) extreme manufacturing concentration (Baxter International alone supplies ~60% of U.S. IV fluid demand), (2) historically low profit margins offering little incentive for manufacturers to maintain safety stockpiles, and (3) catastrophic weather events—Hurricane Maria (2017) and Hurricane Helene (2024)—that knocked out major production capacity.
As of 2026, multiple NDC codes remain on limited availability or manufacturer allocation. Some presentations have recovery timelines extending to September 2026. Availability varies significantly by vial size, NDC code, and geographic region. Hospital pharmacies and infusion providers sourcing through GPO contracts are generally better positioned than retail pharmacies. The FDA declared the broader IV fluid emergency from Hurricane Helene resolved in mid-2025, but SWFI-specific shortages persist.
If you are struggling to find SWFI in stock, medfinder can help. Enter your medication name and ZIP code and medfinder will call pharmacies near you to check current stock—saving you hours of calls. It's a paid service designed for exactly this situation: a critical medication in ongoing shortage.
Sterile Water for Injection is labeled 'Rx only' but is not a DEA-controlled substance. Any licensed prescriber with standard prescribing authority can order SWFI as part of an injectable medication regimen. There are no special DEA registration, schedule, or prescribing restrictions.
Physicians (MDs/DOs): Any specialty. Most commonly: Infectious Disease, Oncology, Endocrinology, Rheumatology, Hospitalists.
Nurse Practitioners (NPs): With full prescriptive authority (most states).
Physician Assistants (PAs): Subject to state-specific collaborative practice requirements.
Pharmacists: In some states with expanded prescribing authority or collaborative practice agreements.
SWFI is primarily prescribed as part of a home infusion therapy program. In practice, the infusion pharmacy supplies SWFI bundled with the injectable medication—patients do not typically fill a separate SWFI prescription at a retail pharmacy. For patients self-injecting hormones, peptides, or other subcutaneous medications, telehealth prescribers can often manage ongoing refills for established patients.
No. Sterile Water for Injection, USP is NOT a controlled substance. It is not scheduled by the DEA under the Controlled Substances Act. There are no DEA registration requirements for prescribing or dispensing SWFI, no quantity limits based on Schedule classification, and no mandatory prescription monitoring program (PMP) reporting requirements.
However, SWFI is labeled 'Rx only' and does require a valid prescription from a licensed prescriber for purchase at licensed medical supply outlets. This is an FDA drug product classification (prescription-only), not a DEA controlled substance designation. Any licensed prescriber (physician, NP, PA) can order SWFI without DEA-specific restrictions, and there are no special storage, logging, or disposal requirements beyond those applicable to any Rx drug.
When used correctly as a diluent, SWFI itself causes no side effects in most adult patients. The small volume of SWFI used to reconstitute a medication has minimal impact on fluid or electrolyte balance in healthy adults. Side effects from injections are attributable to the active drug, not SWFI.
Potential side effects from injection site reactions include:
Phlebitis (vein inflammation): redness, warmth, and tenderness along the vein
Injection site burning or stinging during administration
Fluid and electrolyte imbalance in neonates and very small infants (even small volumes can affect their fluid balance)
Hemolysis: If SWFI is injected undiluted into a vein, it causes red blood cell destruction (labeled warning: 'NOT ISOTONIC. HEMOLYTIC.'). Symptoms: dark/brown urine, back pain, jaundice, anemia.
Infection/sepsis: If sterility is breached during handling, injection of a contaminated solution can cause serious bloodstream infection. Fever, chills, and rapid heart rate are warning signs.
Benzyl alcohol toxicity (Bacteriostatic Water only): Bacteriostatic Water for Injection contains 0.9% benzyl alcohol, which is toxic in neonates and can cause 'gasping syndrome.'
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Bacteriostatic Water for Injection
Contains 0.9% benzyl alcohol preservative; allows multi-dose use up to 28 days; contraindicated in neonates and for intrathecal/epidural routes; generally more available than SWFI at some suppliers
0.9% Sodium Chloride Injection (Normal Saline)
Most commonly used IV fluid; isotonic; acceptable alternative for many antibiotics and other drugs; risk of crystallization at high concentrations with some drugs (e.g., cefazolin >225 mg/mL)
Dextrose 5% in Water (D5W)
Alternative IV diluent for some medications; not universally compatible—confirm drug-specific compatibility before use
Commercially Premixed IV Formulations
Pre-made IV bags of many common antibiotics (vancomycin, piperacillin-tazobactam, meropenem) that require no reconstitution; eliminates SWFI dependency entirely where available
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Benzyl Alcohol (Bacteriostatic Water)
majorBacteriostatic Water contains benzyl alcohol which is toxic in neonates (gasping syndrome) and contraindicated for intrathecal/epidural routes. Never substitute BWFI for SWFI in these contexts.
High-Concentration Cefazolin (≥225 mg/mL)
moderateReconstituting high-concentration cefazolin with Normal Saline instead of SWFI risks crystallization. At these concentrations, SWFI is specifically required per prescribing information.
Alteplase (tPA)
majorAlteplase 2 mg unit-of-use vials require preservative-free SWFI specifically; Bacteriostatic Water cannot be substituted due to benzyl alcohol incompatibility.
Multiple Drugs Combined in Same SWFI Vehicle
moderateCombining multiple drugs in SWFI may cause incompatibility, precipitation, or degradation. Always confirm compatibility before mixing drugs in the same diluent.
Sterile Water for Injection is a foundational pharmaceutical product—seemingly simple but critically important. Its ongoing shortage since 2021 reflects a broader fragility in the U.S. pharmaceutical supply chain: concentrated manufacturing, low margins, and geographic vulnerability. For patients who depend on injectable medications requiring SWFI, the shortage is not abstract—it's a day-to-day challenge that can delay critical therapies.
If you're facing shortage-related access problems, work closely with your prescriber and pharmacist to explore clinically appropriate alternatives (Bacteriostatic Water, Normal Saline, premixed formulations), and plan refills further in advance than usual. The situation continues to improve as Baxter's North Cove facility recovers, but localized gaps and allocation restrictions remain through 2026.
For help finding Sterile Water for Injection in stock near you, medfinder is the fastest tool available. Enter your medication details and let medfinder call pharmacies near you to check stock—then receive results by text. It's a paid service built for exactly this scenario: finding a hard-to-locate medication during an active shortage.
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