ALTHOUGH the long-standing practice of changing needles between drawing up a medication and administering an injection is widely taught, recent research indicates that this habit may provide little benefit while carrying meaningful costs and risks. For many of us, the rationale for switching needles comes from the idea that puncturing a vial stopper dulls the needle tip. The belief is often passed down as accepted wisdom – many practitioners were simply taught to do it this way. Historically, this guidance appears to have migrated from human nursing practice, where multidose vial sterility was once a major concern and rubber septa were thought to damage needles. Veterinary medicine adopted many of these aseptic routines decades ago, long before modern manufacturing improvements. However, recent studies offer a clearer picture. An investigation using force-gauge testing and microscopic imaging found that one or two passes through a vial stopper caused only minor increases in penetration force.1 These changes were smaller than normal variations between needle brands and gauges. Clinical outcomes tell a similar story – a controlled study on dogs in 2025 found no significant difference in patient reactions between injections given with a fresh needle and those using the same needle that drew up the vaccine.2 Notably, staff could not reliably distinguish between the two. “While the benefits of switching needles appear minimal, the downsides are more substantial Taken together, current evidence does not support routine needle changes between vial draw up and injection for the purpose of reducing dullness or improving patient comfort. The practice increases sharps handling, waste and operating costs without offering measurable clinical benefit. I hope this summary helps inform our shared approach to safe, efficient practice. I would welcome further discussion.
Douglas Paterson (Fri,) studied this question.
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