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Epinephrine injection into lower thigh recommended in overweight children

Obese and overweight children should get epinephrine injected into the lower rather than upper half of the thigh to ensure proper delivery of the drug, according to study results presented at the 2013 Annual Meeting of the American Academy of Allergy, Asthma & Immunology.

“Delivering epinephrine into the muscle allows for more rapid absorption and leads to higher blood levels than if it’s injected into the overlying fat. Considering the rising obesity rates in children, there is concern that epinephrine auto-injectors will not adequately deliver the medication in overweight children who may be experiencing anaphylaxis,” Peter D. Arkwright, MD, PhD, senior lecturer in pediatric immunology, University of Manchester, Royal Manchester Children’s Hospital, United Kingdom, said in a press release. “Without proper treatment, anaphylaxis can be fatal, so it’s extremely important that epinephrine is administered quickly and effectively”

The study measured skin surface to muscle depth by ultrasound at set distances down the thigh and leg in 93 children attending regional pediatric allergy clinics. Weight, height and waist circumference also were measured, and BMI was calculated.

Receiver operating characteristic curve analysis showed that higher weight, BMI and waist circumference were associated with a skin surface to muscle depth greater than the auto-injector needle length.

Researchers said at one-quarter the distance down the thigh, 82% of obese children and 25% of non-obese children had skin surface muscle depth greater than needle length. Three-quarters of the way down the thigh, skin surface to muscle depth was greater than needle length in 17% of obese children and 2% of non-obese children. All children had skin surface to muscle depth less than the auto-injector needle length halfway down the calf.

“Based on our study, injecting epinephrine into the lower rather than upper thigh would be advised in overweight or obese children,” Arkwright said. “If a child is experiencing anaphylaxis, this information would be important for a care giver to know so that epinephrine can be administered into the child’s muscle the most effective way.”

For more information:

Arkwright P. Abstract #713. Presented at: 2013 Annual Meeting of the AAAAI; Feb. 22-26, 2013; San Antonio.

Disclosure: Arkwright reports no relevant financial disclosures.