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


METHODS
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.


METHODS
Tertiary care clinic.


METHODS
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<.05); 32% of the intervention arm responded in terms of improved sensitivity towards some of the odours. Minor adverse effects noted included sore throat, nasal paraesthesia, slight rhinorrhoea and itching. The duration of effect of the citrate is transient, peaking at 30-60 minutes after application.


CONCLUSIONS
Sodium citrate yields some potential as a treatment for non-conductive olfactory loss; however, these findings require corroboration in further clinical trials looking at longer term regular use of the spray as a viable therapeutic option for patients where it would be applied at frequent intervals such as before mealtimes.
Norwich Medical School, University of East Anglia, Norfolk, UK.|The Smell & Taste Clinic, ENT Department, James Paget University Hospital NHS Foundation Trust, Gorleston, Norfolk, UK.
C M
http://orcid.org/0000-0002-1125-3236
CM
Philpott
The Smell & Taste Clinic, ENT Department, James Paget University Hospital NHS Foundation Trust, Gorleston, Norfolk, UK.
S E
SE
Erskine
Norwich Medical School, University of East Anglia, Norfolk, UK.
A
A
Clark
The Smell & Taste Clinic, ENT Department, James Paget University Hospital NHS Foundation Trust, Gorleston, Norfolk, UK.
A
A
Leeper
ENT Department, The Ipswich Hospital NHS Foundation Trust, Ipswich, Suffolk, UK.
M
M
Salam
The Smell & Taste Clinic, ENT Department, James Paget University Hospital NHS Foundation Trust, Gorleston, Norfolk, UK.
R
R
Sharma
ENT Department, University Hospitals of Leicester NHS Foundation Trust, Leicester, UK.
G E
GE
Murty
The Smell & Taste Clinic, Department of ORL, Technical University, Dresden, Germany.
T
T
Hummel
D000281:Administration, Intranasal; D002021:Buffers; D002951:Citrates / Q000627:therapeutic use*; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008297:Male; D059085:Nasal Sprays; D000857:Olfaction Disorders / Q000188:drug therapy*; D000077559:Sodium Citrate; D016896:Treatment Outcome
D002021:Buffers; D002951:Citrates; D059085:Nasal Sprays; D000077559:Sodium Citrate
clinical trial; olfaction disorders; smell; sodium citrate; viral respiratory tract infections