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NCT Number: NCT07171320

The Efficacy and Safety of Pregabalin Combined With Desvenlafaxine in Patients With Fibromyalgia

Fibromyalgia (FM) is a chronic pain syndrome characterized by widespread pain, fatigue, and emotional disorders. Its onset is related to factors such as central sensitization and imbalance of neurotransmitters. The current mainstream treatments include pregabalin, but the efficacy of pregabalin is limited, with only 25%-40% pain relief rate, and adverse reactions are common. Selective serotonin and norepinephrine reuptake inhibitors (SNRIs), such as duloxetine and venlafaxine, have demonstrated efficacy in FM by modulating pain pathways through increased serotonin and norepinephrine availability. Desvenlafaxine, the third SNRI, was found with lower adverse effects compared with duloxetine and venlafaxine. We hypothesize that the combination of pregabalin with desvenlafaxine may offer greater pain relief compared pregabalin monotherapy, without a significant increase in adverse effects for patients with FM.

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Key information

Conditions

Fibromyalgia Muscular Diseases Musculoskeletal Diseases Nervous System Diseases Neurologic Manifestations Neuromuscular Diseases Pain Pathological Conditions, Signs and Symptoms Pregabalin Rheumatic Diseases Signs and Symptoms

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Beijing Tiantan Hospital, Beijing, Beijing 100070

Beijing, China

Location status: Recruiting

Location contact

Fang Luo, M.D.

CONTACT

[email protected]

+86 13611326978

Who can participate

Healthy volunteers accepted: No

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

Inclusion criteria

  • Diagnosed with FM according to the 2016 Revisions to the 2010/2011 FM diagnostic criteria;
  • Aged 18 years or older;
  • Experiencing moderate to severe FM that have not been effectively alleviated by non-pharmacological treatments and has not received currently recommended pharmacological treatment for FM;
  • Numeric rating scale (NRS) score ≥ 4 at baseline;
  • Aspartate aminotransferase and alanine aminotransferase levels less than twice the upper limit of normal;
  • Estimated glomerular filtration rate of 30 mL/min per 1.73 m2 or higher;
  • Willing to sign the informed consent form and possessing sufficient cognitive and language abilities to comply with all the study requirements.

Exclusion criteria

  • History of hypersensitivity to pregabalin, desvenlafaxine or any of its excipients;
  • History of epilepsy, or depression requiring antidepressant medications;
  • Pregnancy or breastfeeding;
  • Presence of serious systemic diseases, including uncontrolled hypertension, uncontrolled diabetes, or significant cardiac dysfunction;
  • With acute or chronic pain conditions other than FM.

Treatment and study plan

Pregabalin

Drug

In the pregabalin monotherapy group, pregabalin will be initiated at 150 mg daily, divided into 2 or 3 doses per day, and increased to 300 mg per day after 3 to 7 days, subsequent increases of 150 mg daily may occur every 3 to 7 days, based on individual patient response and tolerability, with a maximum dose of 600 mg daily.

Pregabalin with desvenlafaxine

Drug

In the pregabalin with desvenlafaxine group, the dose titration of pregabalin is identical with pregabalin monotherapy group. Desvenlafaxine will be administered at 50 mg daily with breakfast initially. If the initial dose is well-tolerated, the dose could be further escalated by 50 mg per day after 3 days, up to a maximum of 400 mg per day after 7 days. With each dose increase, AEs will be assessed and categorized as mild, moderate, or severe. If participants tolerate the current dose for 2 to 3 days, it will be maintained, with the expectation that tolerance to AEs will develop. If AEs become intolerable, the dose will be decreased back to the previous dose, which was defined as the maximum tolerated dose. In the combination group, dose titration of both pregabalin and desvenlafaxine will be conducted simultaneously. If AEs occur, the next dose regimen should be determined in consultation with a clinical physician.

Primary outcomes

  1. The average pain intensity

    Time frame: at the 4-weeks

    The average pain intensity over the past 24 hours, rated each morning upon awakening and averaged over 7 days at the 4 weeks. This will be measured based on NRS, where 0 represents no pain and 10 represents worst pain imaginable.

Secondary outcomes

  1. The worst pain intensity

    Time frame: At the weeks 1, 2, 4, and 8

    The worst pain intensity over the past 24 hours, rated each morning upon awakening and averaged over 7 days. The pain intensity will be measured based on NRS, where 0 represents no pain and 10 represents worst pain imaginable.

  2. The proportion of patients achieving pain reduction

    Time frame: At the weeks 1, 2, 4, and 8

    The proportion of patients achieving a ≥ 50% and ≥ 30% reduction in mean baseline pain intensity. The pain intensity will be measured based on NRS, where 0 represents no pain and 10 represents worst pain imaginable.

  3. The Revised FM Impact Questionnaire

    Time frame: At the weeks 1, 2, 4, and 8

    The Revised FM Impact Questionnaire assesses the severity of FM symptoms and their impact on daily functioning. It evaluates three linked domains: function, overall impact, and symptoms, using a 0 to10 NRS. The total score ranges from 0 to 100, with higher scores indicating greater disease burden.

  4. The Brief Pain Inventory (BPI) severity (BPI-S) and interfere (BPI-I) subscales

    Time frame: At the weeks 1, 2, 4, and 8

    BPI-S accesses pain intensity over the past 24 hours, calculated as the average of items 3 to 6 on the BPI, scored using a 0 to 10 NRS. In the NRS scale, 0 indicates no pain, while 10 represents the worst pain imaginable. The total score ranges from 0 to 40, with higher scores indicating greater pain severity. BPI-I evaluates the degree to which pain interferes with daily activities, including general activity, mood, mobility work, relationships, sleep, and pleasure. This subscale comprises 7 items, each scored from 0 (no interference) to 10 (complete interference), with a total score ranging from 0 to 70.

  5. The short-form 36 Health Survey (SF-36)

    Time frame: At the weeks 1, 2, 4, and 8

    The SF-36 assesses health-related quality of life, capturing preferences across various health states. It assesses 8 dimensions: physical functioning, physical role limitations due to physical health, bodily pain, general health, vitality, social functioning, emotional role limitations due to emotional problems, and mental health. Scores range from 0 to 100 for each dimension, with higher scores indicating better health status.

  6. The Medical Outcomes Study Sleep Scale (MOS)

    Time frame: At the weeks 1, 2, 4, and 8

    The MOS is a questionnaire comprising 12 items that assess various aspects of sleep using a 6-point ordinal scale (1 indicating permanence and 6 indicating absence).

  7. The Beck Depression Inventory-Ⅱ (BD-Ⅱ)

    Time frame: At the weeks 1, 2, 4, and 8

    The BD-Ⅱ evaluates the severity of depressive symptoms using a 4-point scale from 0 to 3, where 0 indicates no symptom and 3 indicates severe symptomatology. It comprises 21 items, the total score ranging from 0 to 63.

  8. Adverse Events

    Time frame: Through study completion, an average of 8 weeks

    The incidence and proportion of adverse events will be recorded and categorized as mild, moderate, severe, or life-threatening. AEs are defined as events that arise during treatment, were absent before treatment, or worsen relative to the pretreatment state.

Study contacts

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

Fang Luo, M.D.

CONTACT

[email protected]

+86 13611326978

Sponsors and collaborators

Lead sponsor

Beijing Tiantan Hospital

Other

Collaborators

  • Jiujiang University Affiliated Hospital

Registry information

Official study title

Comparing the Efficacy and Safety of Pregabalin Monotherapy With Pregabalin Combined Other Neuromodulatory Drugs (Desvenlafaxine) in the Treatment of Fibromyalgia: A Multicenter Clinical Study

Important dates

Study start
2025
Primary completion
2027
Study completion
2027
First posted
Sep 12, 2025
Registry last updated
Nov 17, 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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