Safety of intranasal human insulin: A review

Aims To conduct a review in order to assess the safety of intranasal human insulin in clinical studies as well as the temporal stability of nasal insulin sprays. Material and methods An electronic search was performed using MEDLINE. We selected original research on intranasal human insulin without further additives in humans. The studies included could be of any design as long as they used human intranasal insulin as their study product. All outcomes and adverse side effects were extracted. Results A total of 38 studies in 1092 individuals receiving acute human intranasal insulin treatment and 18 studies in 832 individuals receiving human intranasal insulin treatment lasting between 21 days and 9.7 years were identified. No cases of symptomatic hypoglycaemia or severe adverse events (AEs) were reported. Transient local side effects in the nasal area were frequently experienced after intranasal insulin and placebo spray, while other AEs were less commonly reported. There were no reports of participants being excluded as a result of AEs. No instances of temporal stability of nasal insulin were reported in the literature. Tests on insulin that had been repacked into spray flasks showed that it had a chemical stability of up to 57 days. Conclusions Our retrospective review of published studies on intranasal insulin did not reveal any safety concerns; however, there were insufficient data to ensure the long‐term safety of this method of chronic insulin administration. Improved insulin preparations that cause less nasal irritation would be desirable for future treatment.