NCT06253806CompletedPhase 2
Stellate Ganglion Block for COVID-induced Parosmia
Stellate Ganglion Block for the Treatment of COVID-19-Induced Parosmia: Double-Blinded, Placebo-Controlled Randomized Clinical Trial
Source: ClinicalTrials.gov · Last updated 10 Nov 2025
Brief summary (registry, in English)
Chronic olfactory dysfunction, both hyposmia and parosmia, from the COVID-19 pandemic is a growing public health crisis with up to 1.2 million people in the United States affected. Olfactory dysfunction impacts one's quality of life significantly by decreasing the enjoyment of foods, creating environmental safety concerns, and affecting one's ability to perform certain jobs. Olfactory loss is also an independent predictor of anxiety, depression, and even mortality. Recent research by our group (unpublished data) and suggests that parosmias, moreso than hyposmias, can result in increased rates of anxiety, depression, and even suicidal ideation. While the pandemic has increased the interest by the scientific community in combating the burgeoning health crisis, few effective treatments currently exist for olfactory dysfunction. Persistent symptoms after an acute COVID-19 infection, or "Long COVID" symptoms, have been hypothesized to be a result of sympathetic positive feedback loops and dysautonomia. Stellate ganglion blocks have been proposed to treat this hyper-sympathetic activation by blocking the sympathetic neuronal firing and resetting the balance of the autonomic nervous system. Studies prior to the COVID-19 pandemic have supported a beneficial effect of stellate ganglion blocks on olfactory dysfunction, and recent news reports and a published case series have described a dramatic benefit in both olfactory function and other long COVID symptoms in patients receiving stellate ganglion blocks. A previous pilot study using stellate ganglion blocks of 20 participants with persistent COVID-19 olfactory dysfunction resulted modest improvements in subjective olfactory function, smell identification, and olfactory-specific quality-of-life, but it lacked a control group. Therefore, we propose a double-blinded, placebo-controlled randomized clinical trial assessing the efficacy of a stellate ganglion block versus saline injection in a total of up to 140 participants with persistent COVID-19-associated olfactory dysfunction.
- Status (registry)
- Completed
- Phase (registry)
- Phase 2
- Study type
- Interventional
- Enrollment
- 48 (actual)
- First submitted
- 9 Feb 2024
- Start date
- 25 Oct 2023
- Primary completion date
- 16 Sept 2024
- Lead sponsor
- Washington University School of Medicine
- Diseases
- Long COVID and ME/CFS
- NCT number
- NCT06253806
What you commit to
- Study type: Interventional · Phase 2
- Participants enrolled: 48
- From 25 Oct 2023 to the primary completion date, 16 Sept 2024
- 1 site in 1 country
- Visits and tests: ask the trial team, the registry does not list them
Built from the registry fields of ClinicalTrials.gov. It describes the study, not your situation.
Who cannot take part
Copied verbatim from ClinicalTrials.gov and grouped by topic. Only the trial team decides who can take part.
Prior treatment
- History of smell loss or change prior to COVID-19 infection
- History of conditions known to impact olfactory dysfunction
- Chronic rhinosinusitis
- History of prior sinonasal or skull base surgery
- Neurodegenerative disorders (Parkinson's disease, Huntington's disease, Amyotrophic Lateral Sclerosis, Lewy body dementia, frontotemporal dementia)
- Currently using concomitant therapies specifically for the treatment of olfactory dysfunction
- Currently taking blood thinners or antiplatelet agents, including aspirin \>81mg.
- History of prior stellate ganglion block
Other illness
- History of coexisting conditions that make SGB contraindicated:
- Unilateral vocal cord paralysis
- Severe COPD (FEV1 between 30-50% of predicted)
- Recent myocardial infarction within the last year
- Glaucoma
- Cardiac conduction block of any degree
- Allergy to local anesthetic
Other
- Inability to tolerate a needle injection into the neck
- Inability to extend the neck for any reason (e.g., severe arthritis)
Who the study is looking for
- Adults age 18 to 70
- Diagnosis of COVID at least 6 months prior to study enrollment with self-reported parosmia
- Ability to read, write, and understand English
- Score of at least 40 on DiSODOR during screening and at least 25 during Visit 1
Age in the registry: 18 years to 70 years · Sex: All · Does not accept healthy volunteers
Sites (1)
Sites in registry order. Pick your city on the disease page to sort them by distance.
| Site | City | Country | Site status |
|---|---|---|---|
| Nyssa Fox Farrell Coordinator of this site? Confirm its status | St Louis | United States | Unknown status |
This page is information, not medical advice. Discuss any trial with your doctor.