Intranasal sodium citrate in quantitative and qualitative olfactory dysfunction: results from a prospective, controlled trial of prolonged use in 60 patients

Abstract

Objectives We have previously shown that treatment with intranasal sodium citrate may be beneficial in post-infectious olfactory dysfunction. Sodium citrate reduces free intranasal calcium and is, therefore, thought to prevent calcium-mediated feedback inhibition at the level of the olfactory receptor. We aimed to determine whether treatment with a 2-week course of intranasal sodium citrate improves quantitative olfactory function in patients with post-infectious impairment. We also aimed to determine whether sodium citrate is beneficial in treating qualitative olfactory dysfunction. Methods We performed a prospective, controlled study. Patients applied intranasal sodium citrate solution to the right nasal cavity for 2 weeks. The left nasal cavity was untreated and, therefore, acted as an internal control. Monorhinal olfactory function was assessed using the “Sniffin’ Sticks” composite ‘TDI’ score, before and after treatment. The presence of parosmia and phantosmia was also assessed. Results Overall, there was a significant increase in TDI after treatment (using the best of right and left sides). Treatment with sodium citrate did not significantly improve quantitative olfactory function, compared to control. The proportion of patients reporting parosmia did not change significantly after treatment. However, there was a significant reduction in the proportion of patients reporting phantosmia, at the end of the study period. Conclusions Treatment with intranasal sodium citrate for a period of 2 weeks does not appear to improve quantitative olfactory function in patients with post-infectious impairment, compared to control. It may, however, be beneficial in treating phantosmia, which should be further addressed in future work.

International consensus statement on allergy and rhinology: Olfaction

“…In a prospective observational study, the duration of effect subjectively reported by patients was 3 hours. 1807 The subsequent study by Whitcroft et al 1806 that looked specifically at PIOD showed an effect on combined threshold and identification scores, but not separately. 1806 The method of application differed among the four studies.…”

Parosmia—a common consequence of covid-19

“…Intranasal treatments such as topical corticosteroids have been trialled in olfactory loss and subsequently applied to parosmia, although there is little evidence to support this. A small trial of intranasal sodium citrate reported improvements in phantosmia but not parosmia or hyposmia,12 and the results may simply reflect the natural course of the symptoms rather than the effectiveness of treatment. Evidence for other treatments is lacking, although trials are ongoing.…”

Olfactory Dysfunction in Patients With Coronavirus Disease 2019: A Review

“…Numerous drugs exert potential therapeutic effects on OD: vitamin A, theophylline, intranasal sodium citrate, caroverine, alpha-lipoic acid, minocycline, zinc sulfate, and ginkgo biloba ( 112 , 113 , 132 , 133 ). However, except for one case report on vitamin A, clinical studies on their efficacy in COVID-19-induced OD are lacking, so most of these drugs are not recommended for routine use ( 134 ).…”