Epinephrine-Coated Syringes Curb Local Reactions to Immunotherapy

By David Douglas

December 18, 2019

NEW YORK (Reuters Health) - Using epinephrine-coated syringes for subcutaneous immunotherapy (SCIT) lowers the risk of local reactions such as erythema and swelling at injection sites, according to researchers in Thailand.

Such syringes, Dr. Orathai Jirapongsananuruk told Reuters Health by email, "could significantly reduce both immediate and late local reactions (LRs) compared to placebo in patients who have frequent large LRs despite premedication."

In a paper in The Journal of Allergy and Clinical Immunology: In Practice, Dr. Jirapongsananuruk and colleagues at Mahidol University, in Bangkok, note that many strategies to minimize LRs have been reported. Among these are use of oral antihistamines and leukotriene-receptor antagonists.

However, they add, the effect of coating a syringe with epinephrine prior to drawing the allergen extract for SCIT in patients with frequent large LRs has never been explored.

To do so, the team recruited 17 patients. All were more than 6 years old with a minimum lung function (FEV1) of 70% predicted. Despite premedication with antihistamine, with or without leukotriene-receptor antagonist, they complained of having large LRs in at least 20% of injections during the previous five months.

The patients' underlying complaints were asthma and allergic rhinitis with or without allergic conjunctivitis or atopic dermatitis. Among exclusions were patients with symptomatic and uncontrolled asthma.

Participants were allowed to use any previous premedication. They were randomized to receive allergen-extract injections from an epinephrine or saline-coated placebo syringe at their first visit. On their second visit four weeks later they received injections from a syringe coated with the agent that was not used during the first visit.

Measurements at up to six hours showed that use of an epinephrine-coated syringe significantly reduced LRs compared with placebo. At 30 minutes the reduction in size was 100%, but at six hours it had dropped to 39.8%.

The maximum LR following use of the epinephrine-coated syringe was 30% less than that with placebo, a significant difference. There were no systemic reactions.

The researchers call for further studies, but suggest that the mechanism behind the local-reaction reduction "is probably the vasoconstrictive effect that might decrease the absorption rate of the allergen."

SOURCE: https://bit.ly/2sBTSWy The Journal of Allergy and Clinical Immunology: In Practice, online December 3, 2019.