RecruitingPhase IIIInterventional

Testing gabapentin to treat distorted senses of smell after a viral infection

Have you noticed that normal smells, like coffee or food, now smell unpleasant or foul after a viral infection? This is called parosmia, and it's quite common, especially after illnesses like COVID-19. It can really affect daily life, and right now, there aren’t any proven treatments. This study is looking into whether a medicine called gabapentin can help. Gabapentin is already used for nerve pain and epilepsy, where it works by calming overactive nerves. Researchers think it might help by calming the mixed-up smell signals in parosmia. The main goal is to see if gabapentin is a safe and effective way to treat this issue, which could offer real hope to many people.

At a glance

Status

Recruiting

Phase

Phase III

Sponsor

University College London

Enrolment target

Start

13 Oct 2025

Estimated completion

01 Mar 2027

Post-viral Parosmia (distorted smell)

What is this study about?

Imagine your favourite food suddenly smelling awful, or your morning coffee making you feel sick. This is what living with parosmia is like. It's when your sense of smell gets distorted, often after a viral infection such as COVID-19. For many people, this can significantly impact their quality of life, making everyday activities, like eating, very difficult.

Currently, there aren't any specific medicines proven to cure parosmia. This research is a 'Phase III' trial, which means it's testing a new treatment on a larger group of people to see if it works and is safe. The medicine being tested is called gabapentin. It's already used for other conditions like nerve pain and epilepsy, where it helps to calm down overactive nerves. The idea behind this study is that gabapentin might be able to calm the unusual signals that cause the distorted smells in parosmia.

The main aim of this study is to find out if gabapentin can actually reduce the symptoms of parosmia for people who developed it after a viral infection. If it proves to be safe and effective, it could become a new and much-needed treatment option, offering relief and improving the daily lives of many who struggle with this challenging condition.

Key takeaways

The study is testing if gabapentin can help people with distorted smell (parosmia) after a virus.
Parosmia is when normal smells become unpleasant, impacting daily life.
Gabapentin is a medicine that calms nerves and is hoped to reduce these distorted smell signals.
It's a 12-week study; participants will receive either gabapentin or a dummy pill (placebo).
Neither you nor the researchers will know which treatment you are taking.
The study aims to find a new, effective treatment for post-viral parosmia.

Who may be eligible?

To be able to join this study, you need to be an adult between 18 and 65 years old. You must have had parosmia for at least 3 months, but no longer than 3 years, after a viral illness (this includes COVID-19). Your parosmia symptoms should be affecting you noticeably, and you need to be able to understand English well enough to fill in questionnaires.

There are also some reasons why you might not be able to take part. For example, if you have certain allergies, kidney or liver problems, or a history of significant mental health conditions or certain brain-related illnesses like epilepsy or Parkinson's. You also wouldn't be able to join if you've recently taken certain medicines for depression, anxiety, or nerve pain, or other specific medications that might interfere with the study drug.

If you are a woman who could become pregnant, you would need to agree to use effective contraception throughout the study. You would also have a pregnancy test at the start of the study. This is to ensure safety for everyone involved.

Could this study suit you?

Answer these quick questions to see if you may be eligible. This is a guide only — the research team makes the final call.

Are you between 18 and 65 years old?
Have you had parosmia for at least 3 months but less than 3 years after a viral illness (e.g., COVID-19)?
Do you speak and understand English well enough to fill out questionnaires?
Do you have any significant kidney, liver, or brain conditions?
Have you recently experienced specific mental health concerns or taken certain antidepressant/anxiety medications?
If you are a woman who could become pregnant, are you willing to use effective contraception throughout the study?

Answer every question to see your result.

What does participation involve?

If you decide to take part in this study, you would first have a check-up to make sure you're suitable. The study lasts for a total of 12 weeks. You would be randomly placed into one of two groups: one group will receive gabapentin, and the other will receive a 'placebo'. A placebo looks exactly like the real medicine but contains no active ingredients. Neither you nor the study doctors will know which treatment you are getting (this is called 'double-blind').

Throughout the 12 weeks, you will take the study capsules as instructed. You'll complete a special questionnaire about your sense of smell at the very beginning of the study, again after 8 weeks of treatment, and one final time at 12 weeks when the study concludes. Your involvement will wrap up after that 12-week period.

Potential risks and benefits

Because this information wasn't available at the time of registration, we can't tell you the specific benefits or risks designed for this study. In general, potential benefits of taking part in a clinical trial might include getting access to a new treatment before it's widely available and helping doctors learn more about your condition. However, there's no guarantee that the treatment will help you personally. Potential risks could include side effects from the medication or the time commitment involved. It's really important that you understand that you can leave the study at any time, for any reason, without it affecting your usual medical care.

Locations (2)

Some site locations are approximate. We're improving this — please verify with the trial team before travelling.

Homerton Healthcare NHS Foundation Trust
City only
London, United Kingdom
James Paget University Hospitals NHS Foundation Trust
City only
Great Yarmouth, United Kingdom

Common questions

What is parosmia?

Parosmia is when ordinary smells (like food or coffee) become distorted and smell unpleasant, often after a viral infection.

What is gabapentin?

Gabapentin is a medicine currently used for nerve pain and epilepsy that helps calm overactive nerves.

What is a placebo?

A placebo is a fake medicine that looks like the real thing but has no active ingredients. It's used for comparison in studies.

Will I know if I'm getting the real medicine?

No, neither you nor the doctors will know if you're getting gabapentin or the placebo. This is called a 'double-blind' study.

How long will I be in the study?

You will be involved in the study for a total of 12 weeks.

How to find out more

Andrew Tunstell

a.tunstell@ucl.ac.uk +44 20 3447 5369 Official trial record

Always speak to your GP or specialist before deciding to take part in a study.