A randomised controlled trial of sodium citrate spray for non-conductive olfactory disorders

Abstract

Objectives: Previous research has suggested that sodium citrate improves hyposmia by decreasing mucus calcium levels in the nose. This study aimed to confirm or refute this effect in a single application and assess potential side-effects. Design: Study design was a randomised double-blind controlled trial of sodium citrate nasal spray (intervention) vs sterile water (control). Fifty-five patients with non-conductive olfactory loss were randomised to receive the intervention or placebo. Setting: Tertiary care clinic. Main outcome measures: The primary outcome measure was improvement in measured olfactory thresholds for phenyl ethyl alcohol (PEA) over 2 hours. Other outcome measures assessed were improvement in olfactory thresholds in 1-butanol, eucalyptol and acetic acid; number of responders with a clinically relevant response in each arm; and adverse effects. Results: A significant effect was seen in the intervention arm for PEA and for 1-butanol and eucalyptol when compared to the control arm (P