Impact of Storage Temperature on Prevalence of Adverse Events in Nasal Saline Sprays: Exploratory Analysis of Post-market Clinical Follow-Up Data

Introduction Nasal saline sprays are widely used for nasal hygiene and symptomatic relief in upper respiratory conditions. While nasal saline sprays are generally safe and well tolerated, the impact of storage conditions (particularly temperature) on their safety has not been evaluated. This post hoc exploratory analysis of data from three Post-Market Clinical Follow-Up (PMCF) studies investigated the association of storage temperature and prevalence of user-reported adverse events (AEs) across four nasal sprays: Otrivin Sea Water (OSW), Otrivin Sea Water with Aloe Vera (OSWAV), Otrisal 0.74% NaCl Metered-Dose Spray (MDS), and Prorhinel (Haleon plc, Weybridge, UK). Methods The analysis included all subjects from the Modified Intention to Treat (mITT) population across three pooled PMCF studies that evaluated the percentage of subjects who stored the sprays at room temperature (RT) (20-22 °C (68-72 °F)), at temperatures above RT (> 20-22 °C (68-72 °F)), and below RT (4-20 °C (40-68 °F)) and reported AEs. Odds ratios were calculated to assess the impact of storage temperature on the prevalence of AEs. Results Storage outside the RT was associated with increased risk of AEs across nasal saline spray products. The odds of experiencing an AE were approximately 8.94 times higher for OSW, 4.48 times higher for OSWAV, and 4.32 times higher for Prorhinel when stored outside RT, compared with storage within RT. When combined, the Bag of Value (BoV) products (OSW + OSWAV + Prorhinel) showed an overall odds ratio of 4.85 for the occurrence of AEs. Notably, storage above RT was linked to the highest AEs risk, with odds ratios of 15.32 and 14.87 for OSW and OSWAV, respectively. However, no AEs were reported in subjects when Otrisal MDS was stored outside RT. Conclusion This analysis demonstrated a significant correlation between storage temperatures outside RT and increased rates of AEs. These findings reinforce the current guidance provided in the instructions for use of nasal sprays, supporting RT as the optimal in-use temperature to ensure product safety.