Why “Spiking” Vials and Prefilling Syringes Are Not Recommended
Patients are always looking for ways to make weekly testosterone injections more convenient. Two practices we are seeing more frequently are “spiking” testosterone vials by leaving a vial spike or adapter inserted between injections and prefilling multiple syringes days or weeks in advance.
While these practices may save a few minutes, neither is considered a best practice or safe. Testosterone should remain in its original vial until the time of injection, and each dose should be drawn up immediately before administration.
What Is “Spiking”?
“Spiking” is the practice of inserting a plastic vial spike or adapter into a testosterone vial and leaving it in place between injections. The spike eliminates the need to puncture the vial’s rubber stopper with a needle each time a dose is withdrawn.
Although convenient, leaving a spike inserted in the vial is not recommended.
Why These Practices Are Not Recommended
Increased Risk of Contamination
Every time medication is handled or transferred, there is an opportunity for contamination. Leaving a vial spike in place between injections may compromise the vial’s protective barrier, while prefilled syringes undergo additional handling and prolonged storage outside their original container. Both practices can increase the risk of contamination.
Medication Stability
Testosterone products are intended to be stored in their original vial until use. Long-term storage in a plastic syringe has not been validated for stability, and prolonged contact with plastic components—whether in a syringe or a vial spike—is not considered a best practice.
Material Compatibility Concerns
Prolonged contact between the medication and the plastic spike or adapter may cause the plastic to degrade, weaken or leach particles or chemicals into the solution. Additionally, leaving a spike in the stopper can prevent it from resealing properly if the device is removed, increasing the risk of contamination.
The Good News
Massey Drugs compounds testosterone in ethyl oleate (EO), a lower-viscosity carrier oil that is much easier to draw up than many traditional oil-based formulations. Because the medication flows easily, patients can quickly withdraw each dose at the time of injection without the need to leave a vial spike in place or prefill syringes.
Best Practices for Patients
Reminder for Clinics
Please remind your patients not to “spike” testosterone vials or prefill testosterone syringes. Following these simple handling practices helps maintain medication quality and reduces the risk of contamination. To reinforce this message, Massey Drugs has also updated our testosterone patient instruction sheets with this guidance.
The recommendations above are intended to promote appropriate handling and storage of compounded testosterone preparations. Providers should always follow product-specific instructions and use clinical judgment when counseling patients.