Injection Site Reactions Before and After Intramuscular Injection Technique Revision: A Postmarketing Analysis of NALDEBAIN® From 2017 to 2022.

Background: The NALDEBAIN® has been available since 2017, and high incidence of injection reactions in the phase 3 study has been reported. Since the first year in the market, the injection site reactions were still the majority of adverse drug reactions (ADRs) in pharmacovigilance reports. The new intramuscular (IM) instruction and package was introduced in the middle of 2018. In this retrospective study, we analyzed the pharmacovigilance data and published postmarketing studies to investigate the impact of IM injection-related reactions in Taiwan between the period of 2017-2022.

Methods: Individual case safety reports (ICSRs) and ADRs were classified by system organ class and preferred term. The reporting rate of ICSRs was used to evaluate the impact of the new IM instruction and package.

Results: A total of 37 ICSRs were identified from pharmacovigilance reports. Among them, 51% of IM injection-related reactions were reported after one single dose of NALDEBAIN administration. The reporting rate of IM injection-related reactions in pharmacovigilance data dropped from 125.00 to 3.56 per ten thousand exposures after IM instruction and package revision in 2018. In addition, the percentage of IM injection-related reactions also reduced in postmarketing studies from 27.5% to 4.5%. There were no serious IM injection-related reactions found in the pharmacovigilance and postmarketing dataset.

Conclusion: Injection site reactions were common after intramuscularly administered oil-based agents during the first year which is later markedly reduced by changing the length of the needle and injection education.