A recent study conducted in the U.K. found that the injection site may vary depending upon body weight. Using ultrasound to take skin surface to muscle depth measurements, researchers found that higher weight and waist circumference were linked to a skin surface to muscle depth measurement greater than the length of the auto-injector needle. This means the epinephrine was not getting into the muscle where it would be more rapidly absorbed.
The study concluded that it may be beneficial to inject further down the leg where skin surface to muscle depth surpassed the length of the auto-injector needle for a majority of kids.
Talk to your doctor (and share the press release, Injecting Epinephrine into the Lower Rather Than Upper Thigh May Be More Effective in Overweight Children ) if you have concerns about weight and the effectiveness of an epinephrine injector. Make sure that the prescribed auto-injector user and all caregivers are aware of the best place to administer the injection to maximize the benefits of the medication.