Effect of Low Sodium Oxybate (LXB) on Autonomic Symptom Burden in Idiopathic Hypersomnia Patients With Postural Tachycardia Syndrome

The investigators hope to learn if low sodium oxybate (LXB) is an effective treatment for symptoms of idiopathic hypersomnia (IH) and postural tachycardia syndrome (POTS). Previous research has shown that patients with IH also report having symptoms associated with POTS. The researchers have observed that in patients with both IH and POTS, when patients' sleep quality improves, so do their POTS symptoms. The goal of this study is to test this in a controlled way by using LXB as a treatment for both IH and POTS in patients that have been diagnosed with both conditions.

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Key information

Conditions

Idiopathic Hypersomnia Autonomic Nervous System Diseases Disorders of Excessive Somnolence Dyssomnias Mental Disorders Nervous System Diseases Orthostatic Intolerance POTS - Postural Orthostatic Tachycardia Syndrome Postural Orthostatic Tachycardia Syndrome Primary Dysautonomias Sleep Disorders, Intrinsic Sleep Wake Disorders

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 4

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

Age ≥ 18 years
English speaking and capable of signing the informed consent form and comply with the protocol requirements
Diagnosis of IH based on ICSD-3 criteria
Diagnosis of POTS based on the 2011 Consensus Criteria
Oxybate naïve. Participants on daytime alerting medications at baseline can remain on these medications for the duration of the study, provided doses remain stable for the duration of the study. This rule also applies to medications prescribed for the treatment of POTS. All medications known to affect cardiovascular function will be held for the appropriate time periods prior to active stand testing so as not to influence results.
COMPASS 31 ≥ 40 at the screening visit
Agree to use contraceptives consistent with local regulations regarding the methods of contraception for those participating in clinical trials

Exclusion criteria

Hypersomnia due to another medical, behavioral, sleep, or psychiatric disorder
Evidence of untreated or inadequately treated sleep disordered breathing, defined as AHI ≥ 10
History of bipolar or psychotic disorders, major depressive episode, or current suicidal risk
Pregnant or lactating or intends to become pregnant during the study
History of or currently being treated for clinically significant ongoing cardiac arrythmia, heart failure, myocarditis, pulmonary embolism requiring anticoagulation, pulmonary fibrosis or other pulmonary diagnosis that in the investigator's opinion may contribute to symptoms of POTS
Clinically significant uncontrolled active or chronic bacterial, viral, or fungal infection or positive SARS-CoV-2 PCR test at screening
A medical condition that could confound the results of the study or put the participant at undue risk in the investigator's judgment
Intends to have surgery or procedures requiring anesthesia or conscious sedation during the study
Currently participating in another interventional clinical study
Unwilling to remain on a stable regimen of medications during the study
Use of or planned use of intravenous saline infusions during the study

Treatment and study plan

Low sodium oxybate (LXB)

Drug

Participants will continue take low sodium oxybate (LXB) for two weeks after completing an open-label titration and dose optimization period of low sodium oxybate (LXB).

Placebo

Drug

Participants will take placebo for two weeks after completing an open-label titration and dose optimization period of low sodium oxybate (LXB).

Primary outcomes

Overall COMPASS-31 Score as a measure of direct comparison between the two conditions across the two-week randomized withdrawal period.

Time frame: At the end of the two-week randomized withdrawal period

The Composite Autonomic Symptom Severity Scale-31 (COMPASS-31) is an overall assessment of autonomic symptom severity. The scale measures neurodegenerative system symptoms through 31 patient-reported questions. Assessment is through six weighted domains: orthostatic intolerance [10 points]; vasomotor [6 points]; secretomotor [7 points]; gastrointestinal [28 points]; bladder [9 points] and pupillomotor [15 points]. Weighted scores are summed. A higher score indicates worse autonomic dysfunction.

Study contacts

Contact information is provided by the study sponsor or research team.

Jordan Seliger

CONTACT

[email protected]

650-460-9260

Sponsors and collaborators

Lead sponsor

Stanford University

Other

Registry information

Official study title

Effect of Low Sodium Oxybate (LXB) on Autonomic Symptom Burden in Idiopathic Hypersomnia Patients With Postural Tachycardia Syndrome: a Placebo-controlled, Double-blind, Randomized Withdrawal Study

Important dates

Study start: 2025
Primary completion: 2027
Study completion: 2027
First posted: Jul 22, 2025
Registry last updated: Jul 25, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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