Preventing Unsafe Injection Practices

Key points

  • Unsafe injection practices put patients and healthcare providers at risk. This harm is preventable.
  • A good rule to remember is One Needle, One Syringe, Only One Time.

Why it matters

Safe injection practices are every provider's responsibility. A safe injection does not harm the person, expose the provider to risks or result in hazardous waste for the community.1Improper use and disposal of syringes, needles, and medications imposes risks on patients and healthcare providers.

Unsafe injection practices may result in serious consequences like:

  • Transmission of bloodborne pathogens such as hepatitis C virus (HCV), hepatitis B virus (HBV), and human immunodeficiency virus (HIV).
  • Outbreaks of bacterial or fungal infections.
  • Patient notifications about possible outbreaks and exposures to bloodborne or other pathogens, which may include advice on follow-up testing (e.g., for HCV, HBV, and HIV).
  • Provider referrals to licensing boards for disciplinary action.
  • Malpractice suits by patients.


Standard Precautions are the foundation of the CDC guidelines on preventing healthcare-associated infections (HAIs), including injection safety. They reflect the minimum standards that healthcare providers should follow.

Safe injection practices include one-time use of needles and syringes and limiting the sharing of medication vials.

Unsafe injection practices include:

  • Administration of sedatives and anesthetics for surgical, diagnostic and pain management procedures.
  • Administration of IV (intravenous) medications for chemotherapy, cosmetic procedures and alternative medicine therapies.
  • Use of saline solutions to flush IV lines and catheters.
  • Administration of joint injections.

Despite these recommendations, outbreaks and patient exposures due to unsafe injection practices continue. Practices that have resulted in spread of viruses, bacteria, and fungi include:

  • Reusing a syringe for more than one patient. This includes times when the needle is changed or the injection is administered through intravenous (IV) tubing.23
  • Double dipping. For example, accessing a medication vial or container with a syringe that has been used to administer medication to a patient, then using the medication from that container for another patient.4567
  • Reusing single-use medications for more than one patient.8910
  • Failing to use aseptic technique when preparing and administering injections.111213


The following safe injection practices are critical for patient safety:

  • Always use aseptic technique when preparing and administering injections.
  • Use a new sterile syringe and needle for each patient. Once used, the syringe and needle are both contaminated and must be discarded.
  • Do not administer medications from the same syringe to more than one patient, even if the needle is changed or you are injecting through an intervening length of IV tubing.
  • Do not enter a medication vial, bag, or bottle with a syringe or needle used on another patient.
  • Never use medications intended for single use for more than one patient. This includes single-dose vials, ampoules, bags and bottles of intravenous solutions.
  • Limit the use of multi-dose vials and dedicate them to a single patient whenever possible. Reused multi-dose vials should be kept and accessed in a designated clean medication preparation area, away from immediate patient treatment areas.
  • Always use facemasks when injecting material or inserting a catheter into the epidural or subdural space.

Draw up medications in a designated clean medication preparation area that is not adjacent to potential sources of contamination, including sinks or other water sources.

Clean and disinfect the medication preparation area on a regular basis and any time there is evidence of soiling. Have supplies (e.g., alcohol-based hand rub, needles and syringes in their sterile packaging and alcohol wipes) available in the medication preparation area to ensure that staff can adhere to aseptic technique.

The safest practice is to prepare an injection as close as possible to the time of administration. This reduces the risk of compromising the medication's:

  • Sterility: microbial contamination or proliferation.
  • Physical and chemical stability: the loss of potency or adsorption to the container.

If there is a need for pre-drawn syringes, one option is to purchase conventionally manufactured pre-filled syringes. These syringes undergo quality assurance, including sterility and stability, testing by the manufacturer. Another option is to obtain pre-filled syringes from an FDA-registered outsourcing facility. Outsourcing facilities are subject to current good manufacturing practice requirements and other requirements to help assure drug quality.

Do not leave a needle inserted into a medication vial septum for multiple uses. This creates a direct route for microorganisms to enter the vial and contaminate the fluid.

Always discard medication vials whenever sterility is compromised or questionable.

Certain types of manipulation as part of medication preparation may be considered pharmaceutical compounding. Examples include combining two or more medications or creating a batch of pre-drawn syringes. For more information, refer to United States Pharmacopeia (USP) General Chapter 797 and the Sterile compounding section below.14

A single-dose vial of liquid medication intended for injection or infusion is only approved for use in a single patient for a single case, procedure or injection.

Single-dose vials are labeled by the manufacturer and typically lack an antimicrobial preservative. They can serve as a source of infection when used inappropriately or contaminated.

Never use medications packaged as single-dose vials for more than one patient. Consult with pharmacy professionals and USP 797 standards if there is a need to subdivide contents of single-dose vials.

If a single-dose vial appears to contain multiple doses or contains more medication than needed for a single patient, do not retain it for future use, even on the same patient.

Do not combine (pool) leftover contents of single-dose vials or store single-dose for later use.

To prevent waste or the urge to use contents from single-dose vials for more than one patient, select and purchase the smallest vial necessary for your needs.

Discard an unopened single-dose vial according to the manufacturer's expiration date.

A multi-dose vial of liquid medication contains more than one dose of medication and is approved for repeated uses.

Multi-dose vials are labeled by the manufacturer and typically contain an antimicrobial preservative to help limit the growth of bacteria. The preservative does not have an effect on viruses nor does it provide complete protection against bacterial contamination.

Assign medications packaged as multi-dose vials to a single patient whenever possible.

Multi-dose vials that are used for more than one patient should be kept and accessed in a clean medication preparation area away from immediate patient treatment areas.

If a multi-dose vial enters an immediate patient treatment area, dedicate it for single patient use only. Examples of immediate patient treatment areas include operating and procedure rooms, anesthesia and procedure carts, and patient rooms or bays.

The United States Pharmacopeia (USP) General Chapter 797 recommends the following

  • An unopened multi-dose vial should be discarded according to the manufacturer's expiration date.
  • Once a multi-dose vial is opened (e.g., needle-punctured) the vial 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 manufacturer's original expiration date.14

For information on storage and handling of multi-dose vaccine vials please refer to the CDC Vaccine Storage and Handling Toolkit or the manufacturer's recommendations.

Special considerations

Spinal injections

When performing a spinal injection procedure in any healthcare setting:

  • Always use facemasks when injecting material or inserting a catheter into the epidural or subdural space.
  • Use aseptic technique and other safe injection practices (e.g., using a single-dose vial or contrast solution for only one patient) after all spinal injection procedures.15

For other spinal procedures use the aseptic technique and follow safe injection practices. The use of a facemask can be an extra precaution. Other spinal procedures may include diagnostic and therapeutic lumbar punctures or handling of devices to access the cerebrospinal fluid like Ommaya reservoir.

Sterile compounding

The United States Pharmacopeia (USP) develops standards for preparing compounded sterile medications to help ensure patient safety and reduce risks such as contamination, infection or incorrect dosing. The USP chapter on sterile compounding General Chapter <797> Pharmaceutical Compounding – Sterile Preparations defines sterile compounding as "combining, admixing, diluting, pooling, reconstituting, repackaging or altering a drug or bulk drug substances to create a sterile medication." Preparing a syringe with the contents from two or more sterile medication vials falls under USP 797. More information is available in the USP <797> FAQs.

Incremental (repeat) dosing

The safest practice is to use a syringe and needle once to administer medication to a single patient. The syringe and needle should be discarded after use. However, when this is not feasible (e.g., when administration of incremental doses to a single patient from the same syringe is an integral part of the procedure), the reuse of the same syringe and needle for the same patient should occur as part of a single procedure with strict adherence to aseptic technique. In such situations it is essential that the syringe is never left unattended and is discarded immediately at the end of the procedure.

Resources and tools

CDC has factsheets and posters to help providers prevent unsafe injection practices.

  1. World Health Organization best practices for injections and related procedures toolkit. March 2010.
  2. Comstock RD et al. A Large Nosocomial Outbreak of Hepatitis C and Hepatitis B Among Patients Receiving Pain Remediation Treatments. ICHE 2004;25:576-583.
  3. Jain SK et al. Nosocomial Malaria and Saline Flush. EID 2005;11:1097-1099.
  4. Fischer GE et al. Hepatitis C Virus Infections from Unsafe Injection Practices at an Endoscopy Clinic in Las Vegas, Nevada, 2007-2008. CID 2010;51:267-273.
  5. Macedo de Oliveira A et al. An Outbreak of Hepatitis C Virus Infections among Outpatients at a Hematology/Oncology Clinic. AIM 2005;142:898-903.
  6. Moore ZS et al. Hepatitis C Virus Infections associated with Myocardial Infusion Studies, North Carolina, 2008. Poster presented at: Annual Scientific Meeting of the Society for Healthcare Epidemiology; March 21, 2009; San Diego, CA.
  7. Gutelius B et al. Multiple Clusters of Hepatitis Virus Infections Associated with Anesthesia for Outpatient Endoscopy Procedures. Gastroenterology 2010;139:163-170.
  8. Bennett SN et al. Post-operative Infections Traced to Contamination of an Intravenous Anesthetic, Propofol. NEJM 1995;333:147-154.
  9. Groshskopf LA et al. Serratia liquefaciens Bloodstream Infections from Contamination of Epoetin alfa at a Hemodialysis Center. NEJM 2001;344:1491-1497.
  10. Cohen AL et al. Outbreak of Serratia marcescens Bloodstream and Central Nervous System Infections after Interventional Pain Management Procedures. Clin J Pain 2008;24:374-380.
  11. Samandari T et al. A Large Outbreak of Hepatitis B Virus Infections Associated with Frequent Injections at a Physician's Office. ICHE 2005;26:745-750.
  12. Archer WR et al. Methicillin-susceptible Staphylococcus aureus Infections after Intra-Articular Injections. Poster presented at: 47th Annual Meeting of Infectious Diseases Society of America; October 29-November 1, 2009; Philadelphia, PA.
  13. Thompson ND et al. Nonhospital Health Care-Associated Hepatitis B and C Virus Transmission: United States, 1998-2008. Ann Intern Med 2009;150:33-39.
  14. United States Pharmacopeia (USP) 797: Guidebook to Pharmaceutical Compounding – Sterile Preparations. November 1, 2023.
  15. Centers for Disease Control and Prevention. 2007 Guideline for isolation precautions: preventing transmission of infectious agents in healthcare settings. Accessed January 25, 2011.
  • Abe K et al. Outbreak of Burkholderia cepacia Bloodstream Infection at an Outpatient Hematology and Oncology Practice. ICHE 2007;28:1311-1313.
  • Centers for Disease Control and Prevention. Bacterial meningitis after intrapartum spinal anesthesia—New York and Ohio, 2008–2009. MMWR 2010;59(3):65-9.
  • Philips BJ, Fergusson S, Armstrong P, Anderson FM, Wildsmith JA. Surgical face masks are effective in reducing bacterial contamination caused by dispersal from the upper airway. Br J Anaesth. 1992;69(4):407-8.