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Concerns About Air Bubbles in Self-Injectors

8/21/2025, 8:33:09 AMMale25-34

F24 / 149cm / 60kg / chronic migraine patient Greetings, everyone. I have been using a 225mg fremanezumab self-injector every month to manage my chronic migraines. My preferred injection site is my thigh, as I cannot inject into my abdomen or upper arm due to personal limitations. I have a significant fear of needles, and while I’ve made some progress in handling it, a recent incident has heightened my anxiety, bringing me back to where I started. I hope to gather some insights and possibly reassurance regarding a specific concern. Recently, I noticed that there is a small air bubble, around 2mm in size, present in the injector pen. The provider assured me that this bubble should not cause any issues. However, during my last injection, I experienced greater discomfort than usual, leading me to suspect that I may have inadvertently hit a vein or something similar (I typically cool the area beforehand and hardly notice the needle). There was an unusual amount of bleeding—approximately a teaspoon—whereas I usually see only a tiny spot. After this, I spent four hours worrying that the air bubble had entered my bloodstream and couldn't find adequate information on how serious this could be. Unfortunately, my healthcare provider's phone lines are currently unavailable, so I haven’t had the chance to discuss this with them directly. Although I awoke today feeling completely normal, I am trying to gauge how cautious I should be during my next injection. I appreciate any guidance or advice you might have. Thank you!

Multiple SclerosisInternal MedicineRheumatology

Answers (1)

Cony

8/21/2025, 8:33:51 AM

OpenHealth AI

It's understandable to feel anxious about the air bubble in your self-injector and the recent experience you had while injecting. Let's clarify your concerns and provide some reassurance regarding your situation.

Key Points

  • A small air bubble (like the 2mm you mentioned) in an injector pen is generally not a cause for concern.
  • Intravenous air bubbles are usually harmless in small amounts, especially in the context of a self-injection for a medication.
  • The increase in bleeding you experienced may have been due to other factors, such as hitting a blood vessel, rather than the air bubble itself.

Explanation

When using self-injectors, it's common to see tiny air bubbles in the medication chamber. These bubbles do not typically pose a health risk because they are too small to create a harmful effect when injected into the subcutaneous tissue, as they usually come out in the injection. In general, the body can tolerate small amounts of air without complications. However, it's good to be cautious and aware of the injection technique.

Bleeding at the injection site can occur for several reasons:

  1. Hitting a blood vessel, which can increase bleeding.
  2. Injecting too quickly or at an angle that affects blood vessels nearby.
  3. Not applying enough pressure during or after the injection.

Next Steps

  1. Calm Your Mind: Understand that the air bubble is unlikely to cause any harm. If you feel physically fine the next day, it’s a good sign.
  2. Injection Technique:
    • Ensure you are injecting at a 90-degree angle into your thigh.
    • Apply gentle pressure for a few seconds after withdrawing the needle to minimize bleeding.
  3. Site Selection: If possible, consider varying the injection site within your thigh to avoid the same area each time. This can minimize soreness and help with healing.
  4. Injection Confidence: Practice relaxation techniques before the injection, such as deep breathing or visualization, to help manage your anxiety about needles.
  5. Monitor for Changes: Keep a close eye on the site for any signs of infection, such as increased redness, swelling, or warmth, and note any other troubling symptoms.

If you continue to feel anxious or if unusual symptoms occur, it’s important to reach out to your healthcare provider when their lines are available, as they can provide support specific to your situation. You're making progress, and addressing these concerns step by step will help you feel more comfortable with your injections.

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