Phase 2 N=68 Randomized Triple-blind Treatment

Efficacy of Gabapentin for Post-Covid-19 Olfactory Dysfunction

COVID-19 · Olfactory Disorder · Anosmia · Hyposmia · Parosmia

Bottom Line

View on ClinicalTrials.gov: NCT05184192 ↗

Enrolled (actual)

Serious AEs

0.0%

Results posted

Mar 2025

Primary outcome: Primary: Clinical Global Impression of Improvement Scale (CGI-I) — 8; 20; 7; 12 Participants

Study Design & Population

Study type: Interventional
Phase: Phase 2
Interventions: Gabapentin gelatin capsules 300mg (Drug); Placebo (Drug)
Age: Adult, Older Adult · 18+ yrs
Sex: All
Sponsor: Washington University School of Medicine
Primary completion: Aug 2023

Outcome Measures

Outcome	Result	p-value
PRIMARY Clinical Global Impression of Improvement Scale (CGI-I)	8; 20; 7; 12	—
SECONDARY University of Pennsylvania Smell Identification Test (UPSIT)	23; 24; 25; 25; 26; 25	—
SECONDARY Olfactory Dysfunction Outcomes Rating (ODOR)	23; 54.5; 25.5; 49.9; 25; 45	—
SECONDARY NASAL-7	6; 10; 8; 12; 2; 3	—
SECONDARY CGI-Severity of Smell	4; 4; 12; 16; 1; 4	—
SECONDARY CGI-S of Parosmia	7; 6; 9; 8; 2; 7	—

Summary

This study will investigate the efficacy of oral gabapentin in olfactory improvement following Covid-19- associated olfactory dysfunction. This is a randomized, double-blinded, placebo-controlled trial.

Eligibility Criteria

Inclusion Criteria

Men and women between the ages of 18 and 65 years
Residing within the states of Missouri or Illinois
Clinically diagnosed or subjective olfactory dysfunction (anosmia, hyposmia, or parosmia) of 3 months duration or longer diagnosed within 2 weeks of Covid-19 infection
UPSIT score consistent with diminished olfactory function (score ≤ 33 in men and ≤ 34 in women).
Willing to respond daily to study surveys, preferably through smartphone with unlimited texting plan
In possession of ALL 7 household items: soap, burnt candle, peanut butter, herb, garlic, lemon, and coffee

Exclusion Criteria

Clinically diagnosed olfactory dysfunction secondary to genetic abnormalities or congenital dysfunction, trauma, non-Covid-19 viral infection, nasal polyps, neurodegenerative disorders
Current use of: azelastine, bromperidol, orophenadrine, oxomemazine, kratom, paraldehyde, or thalidomide
History of addiction to alcohol, cocaine, or opioids
Impaired renal function, myasthenia gravis, or myoclonus
Severe allergy to peanuts
Pregnancy or attempting pregnancy during study participation
Inability to participate in virtual trial due to lack of access to the internet or unlimited text messaging; inability to comprehend or use English language
Availability less than 6 months from time of enrollment
Residency in states other than Missouri or Illinois.

View full record on ClinicalTrials.gov →

Data sourced from ClinicalTrials.gov (NCT05184192). Outcome figures and adverse-event rates are extracted automatically from the registry's posted results and are provided for clinician reference, not as a substitute for the primary publication.