Intranasal Esketamine-dexmedetomidine Combination in Patients With Postherpetic Neuralgia

November 8, 2026 updated by: Dong-Xin Wang, Peking University First Hospital

Efficacy of Intranasal Esketamine-dexmedetomidine Combination in Patients With Postherpetic Neuralgia: a Randomized, Double-blind, Active Drug-controlled Trial

Postherpetic neuralgia (PHN) is a chronic neuropathic pain syndrome suffered by patients with herpes zoster and often adversely affect patients' normal lives, leading to declines in sleep and quality of life. Ketamine/esketamine has been used for treatment of chronic pain but may produce adverse psychiatric reactions at slightly higher doses, including dissociative symptoms, hallucinations, and nightmares; the sedative effect of dexmedetomidine helps mitigate its psychiatric side effects. A previous study in orthopedic surgery patients also showed that dexmedetomidine combined with esketamine can significantly improve perioperative analgesia and sleep quality. The investigators hypothesize that intranasal administration of dexmedetomidine combined with esketamine in patients with postherpetic neuralgia can improve analgesic efficacy.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Not yet recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

Postherpetic neuralgia (PHN) is a chronic neuropathic pain syndrome suffered by patients with herpes zoster. The typical feature of PHN is deep burning pain in the affected unilateral dermatome, often accompanied by stabbing pain and itching, persisting for more than 3 months after the initial onset of herpes zoster. The incidence of PHN among patients with herpes zoster is approximately 10-20%. The chronic pain symptoms of PHN often adversely affect patients' normal lives, leading to declines in sleep and quality of life. Approximately 50% of PHN patients have sleep disturbances. These ultimately affect cognitive function and mental health.

Ketamine is a non-competitive N-methyl-D-aspartate (NMDA) receptor antagonist and has long been used as a dissociative anesthetic. At subanesthetic doses, ketamine exhibits analgesic and antihyperalgesic effects. Guidelines recommend low-dose ketamine infusion for the treatment of chronic pain. Esketamine is the more potent right-handed enantiomer of ketamine, with stronger affinity for the NMDA receptor; its potency is approximately twice that of ketamine, and the incidence of adverse psychiatric reactions is lower in clinical use. Intranasal esketamine has been approved by the FDA for the treatment of adults with treatment-resistant depression and represents a more non-invasive route of administration.

Dexmedetomidine is a highly selective α2-adrenergic receptor agonist with sedative, analgesic, and anxiolytic effects. Dexmedetomidine acts on the locus coeruleus, inhibiting the release of norepinephrine from neurons in the locus coeruleus and the activity of the medullary-spinal descending neural pathways, thereby producing sedative and analgesic effects. In perioperative management, dexmedetomidine is widely used for postoperative adjuvant analgesia; it can also improve patients' sleep, producing a state resembling non-rapid eye movement sleep. Intranasal dexmedetomidine can be safely used in adults and children and is currently widely used for pediatric procedural sedation and preoperative medication.

Ketamine/esketamine can produce adverse psychiatric reactions at slightly higher doses, including dissociative symptoms, hallucinations, and nightmares; the sedative effect of dexmedetomidine helps mitigate its psychiatric side effects. A previous study in orthopedic surgery patients also showed that dexmedetomidine combined with esketamine can significantly improve perioperative analgesia and sleep quality. The investigators hypothesize that intranasal administration of dexmedetomidine combined with esketamine in patients with postherpetic neuralgia can improve analgesic efficacy.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
80

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Phase 4

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Locations

  • China
    • Beijing Municipality
      • Beijing, Beijing Municipality, China, 100034
        • Peking University First Hospital
        • Contact:

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

50 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • Age ≥ 50 years.
  • Diagnosis of postherpetic neuralgia (PHN) requiring pharmacological analgesia, with a pain score ≥ 4 on the numerical rating scale (NRS).
  • Provision of written informed consent.

Exclusion Criteria:

  • Unsuitability for intranasal administration due to nasal disorders (e.g., rhinitis, nasal polyps, or nasal obstruction from any cause).
  • Inability to communicate owing to severe dementia, coma, or a language barrier.
  • History of schizophrenia, epilepsy, Parkinson's disease, or myasthenia gravis.
  • Previous diagnosis of sleep apnoea, or high risk of moderate-to-severe sleep apnoea on the STOP-Bang assessment, or body mass index > 30 kg/m².
  • History of hyperthyroidism or phaeochromocytoma.
  • Left ventricular ejection fraction (LVEF) < 30%; or sick sinus syndrome, severe sinus bradycardia (heart rate < 50 bpm), or second-degree or higher atrioventricular block without an implanted pacemaker; or systolic blood pressure < 90 mmHg before enrolment.
  • Severe hepatic impairment (Child-Pugh class C); severe renal impairment requiring dialysis; or any ongoing life-threatening condition (e.g., myocardial infarction, cerebrovascular accident, transient ischaemic attack, or coronary stenting within the previous 3 months; active myocardial ischaemia; severe valvular disease; or end-stage renal disease not receiving dialysis).
  • Hypersensitivity to dexmedetomidine and/or esketamine.
  • Participation in another clinical trial, or any other condition that, in the investigator's opinion, makes the patient unsuitable for inclusion.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Quadruple

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: DEX-ESK group

For each administration: dexmedetomidine (1 spray = 0.05 ml = 25 μg) is administered as one spray into each nostril; after 1 minute, esketamine (1 spray = 0.05 ml = 1.25 mg) is administered alternately into each nostril, 4 sprays per nostril. Esketamine administration is repeated every 5 minutes until a total dose of 0.3 mg/kg is reached (using the number of sprays closest to the predetermined dose). If a dose is not tolerated, one administration may be omitted.

Administer once daily for 4 consecutive days, with the same administration method as above.
Drug: Intranasal DEX-ESK combination

For each administration: dexmedetomidine (1 spray = 0.05 ml = 25 μg) is administered as one spray into each nostril; after 1 minute, esketamine (1 spray = 0.05 ml = 1.25 mg) is administered alternately into each nostril, 4 sprays per nostril. Esketamine administration is repeated every 5 minutes until a total dose of 0.3 mg/kg is reached (using the number of sprays closest to the predetermined dose). If a dose is not tolerated, one administration may be omitted.

Administer once daily for 4 consecutive days, with the same administration method as above.

Other Names:
  • Intranasal dexmedetomidine and esketamine
Active Comparator: ESK group

For each administration: placebo (0.9% saline; 1 spray = 0.05 ml) is administered as one spray into each nostril; after 1 minute, esketamine (1 spray = 0.05 ml = 1.25 mg) is administered alternately into each nostril, 4 sprays per nostril. Esketamine administration is repeated every 5 minutes until a total dose of 0.3 mg/kg is reached (using the number of sprays closest to the predetermined dose). If a dose is not tolerated, one administration may be omitted.

Administer once daily for 4 consecutive days, with the same administration method as above.
Drug: Intranasal ESK alone

For each administration: placebo (0.9% saline; 1 spray = 0.05 ml) is administered as one spray into each nostril; after 1 minute, esketamine (1 spray = 0.05 ml = 1.25 mg) is administered alternately into each nostril, 4 sprays per nostril. Esketamine administration is repeated every 5 minutes until a total dose of 0.3 mg/kg is reached (using the number of sprays closest to the predetermined dose). If a dose is not tolerated, one administration may be omitted.

Administer once daily for 4 consecutive days, with the same administration method as above.

Other Names:
  • Intranasal placebo (normal saline) and esketamine

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Sum of pain intensity difference (SPID) within 7 days after the first administration
Time Frame: Within 7 days after the first administration

Follow-up time points: before each administration (Days 1, 2, 3, and 4 of enrollment; face-to-face follow-up); on Days 1, 2, and 3 after the last administration (Days 5, 6, and 7 of enrollment; telephone follow-up at the same time of day as drug administration).

Pain intensity: the patient's NRS pain score over the past 24 hours is recorded (0-10; 0 = no pain at all, 10 = the worst pain imaginable).

Sum of pain intensity difference (SPID): calculated as the sum of (baseline NRS score - NRS score at each scheduled daily follow-up) within 7 days after the first administration (i.e., 3 days after the last treatment).
Within 7 days after the first administration

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Sum of pain intensity difference (SPID) during Weeks 2 to 12 after the first administration
Time Frame: During Weeks 2 to 12 after the first administration

Follow-up time points: once weekly after the last administration until Week 12 of enrollment (Days 14, 21, 28, 35, 42, 49, 56, 63, 70, 77, and 84 of enrollment; telephone follow-up).

Pain intensity: the patient's NRS pain score over the past 24 hours is recorded (0-10; 0 = no pain at all, 10 = the worst pain imaginable).

Sum of pain intensity difference (SPID): calculated as the sum of (baseline NRS score - NRS score at each scheduled weekly follow-up) during Weeks 2 to 12 after the first administration.
During Weeks 2 to 12 after the first administration
Change from baseline in ZBPI chronic pain and impact scores within 3 months after treatment
Time Frame: Up to 3 months after the first administration

Follow-up time points: Days 7 and 14 after the first administration (telephone follow-up); Months 1, 2, and 3 after the first administration (Days 28, 56, and 84 of enrollment; telephone follow-up).

Severity of chronic pain and its impact on patients: assessed using the Zoster Brief Pain Inventory (ZBPI, Appendix 7). Pain severity is rated from 0 to 10, with higher scores indicating greater pain severity; pain interference is rated from 0 to 10 across 7 domains, with higher scores indicating greater interference with daily functioning.

Within 3 months after the first dose
Up to 3 months after the first administration

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Peking University First Hospital

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Dong-Xin Wang, MD, PhD, Peking University First Hospital

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
November 1, 2026

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
November 1, 2027

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
May 1, 2028

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
November 8, 2026

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
November 8, 2026

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
November 13, 2026

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
November 13, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
November 8, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
November 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 2026R0576

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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