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.



Eligible Ages
Between 18 Years and 65 Years
Eligible Genders
Accepts Healthy Volunteers

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.

Study Design

Phase 2
Study Type
Intervention Model
Parallel Assignment
Intervention Model Description
Double-blinded, randomized, placebo-controlled trial
Primary Purpose
Triple (Participant, Investigator, Outcomes Assessor)
Masking Description
double-blinded, both participants and investigators will be blinded. Intervention will be packaged in blinded fashion by pharmacist before being shipped to participants by research assistant

Arm Groups

ArmDescriptionAssigned Intervention
This arm will be given the active treatment, oral Letco (gabapentin) gelatin capsules of 300mg each. Up to the first four weeks will be a titration period (week 1 300mg TID, week 2 600mg TID, week 3 900mg TID, week 4 1,200mg TID) as tolerated. If intolerable adverse reactions occur, the dosage will be decreased to prior tolerable dose (e.g., if 900mg TID is intolerable, dose will be decreased to 600mg TID). The following eight weeks will be fixed dose, the highest tolerable dose from the titration period. Up to two weeks will be a taper down tailored to the maximum dose the participant reached during the titration and fixed periods. A maximum 14 weeks will mark the end of active treatment. Follow-up assessments will be conducted 4 weeks after completion of the taper-down period.
  • Drug: Gabapentin gelatin capsules 300mg
    Gabapentin is an anti-epileptic also used for nerve pain. This study will investigate the efficacy of gabapentin for olfactory nerve recovery and improvement in post-Covid-19 olfactory dysfunction.
    Other names:
    • Letco
Placebo Comparator
Placebo gelatin capsules that look, smell, and taste like gabapentin capsules will be given to the placebo arm. To preserve double-blinding of the study, subjects will receive one capsule TID the first week, the second week two capsules TID, the third week three capsules TID, and fourth week four capsules TID as tolerated. If intolerable, the dose will be decreased to prior tolerable dose. The next eight weeks will be a fixed amount of placebo based on the highest tolerable amount from the titration period. Subjects will then taper-down placebo to imitate the gabapentin arm for maximum two weeks based on highest dose achieved during study. 4 weeks after completion of taper-down, follow-up assessments will be conducted.
  • Drug: Placebo
    lactose monohydrate NF

Recruiting Locations

Washington University
Saint Louis, Missouri 63110
Ashna Mahadev

More Details

Washington University School of Medicine

Study Contact

Jay Piccirillo, MD

Detailed Description

The drug will be given over a maximum 14 weeks with up to four weeks titrating up, eight weeks maintaining highest tolerable dose, and up to two weeks tapering down. Change in olfactory function from baseline to completion of 8-week fixed-dose period will be compared between the two study groups. Follow-up assessments will be conducted for both groups 4 weeks after completion of taper down.


Study information shown on this site is derived from ClinicalTrials.gov (a public registry operated by the National Institutes of Health). The listing of studies provided is not certain to be all studies for which you might be eligible. Furthermore, study eligibility requirements can be difficult to understand and may change over time, so it is wise to speak with your medical care provider and individual research study teams when making decisions related to participation.