What question did this study set out to answer?

This trial aims to evaluate the efficacy and safety of combining pregabalin with tizanidine compared to pregabalin alone in fibromyalgia treatment.

May 16, 2026Open Access

Efficacy and Safety of Pregabalin-Tizanidine vs Pregabalin in Patients with Fibromyalgia: Study Protocol for a Multicenter, Prospective, Randomized, Controlled, Open-Label, Blinded Endpoint Trial

Key Points

This trial aims to evaluate the efficacy and safety of combining pregabalin with tizanidine compared to pregabalin alone in fibromyalgia treatment.
Recruiting 164 adult patients diagnosed with fibromyalgia.
Participants randomly assigned in a 1:1 ratio to pregabalin plus tizanidine or pregabalin monotherapy.
Primary outcome is pain intensity change after 12 weeks, assessed using the Revised Fibromyalgia Impact Questionnaire.
The primary outcome will assess the difference in average pain intensity from baseline to week 12.
Secondary outcomes will evaluate changes in widespread pain, psychological functioning, and health-related quality of life at multiple time points.
Expected findings will provide insights into the combined efficacy of pregabalin and tizanidine.

Abstract

Background: The global prevalence of fibromyalgia (FM) in the general population is estimated to range from 2% to 4%. Pregabalin, a gamma-aminobutyric acid (GABA) analogue, is one of the most widely prescribed medications for FM. However, at therapeutic doses, its limited efficacy and/or unacceptable side effects mean that many patients derive only partial benefit, often leading to treatment discontinuation. Cyclobenzaprine is a centrally acting muscle relaxant. In August 2025, the United States Food and Drug Administration approved a sublingual formulation of cyclobenzaprine hydrochloride for treating FM in adults. However, its availability is largely confined to North America. Tizanidine, like cyclobenzaprine, is also a muscle relaxant with a central mechanism; however, there is no codified posology for FM treatment with tizanidine. Methods: This study aims to recruit 164 adult patients diagnosed with FM. Participants will be randomly assigned in a 1:1 ratio to either the intervention group (pregabalin plus tizanidine) or the control group (pregabalin monotherapy). The primary outcome is the change from baseline to week 12 in average pain intensity (during the last 7 days) assessed using the first item of the symptom domain of the Revised Fibromyalgia Impact Questionnaire (FIQR). Secondary outcomes, assessed at weeks 4, 8, 12, 16, 20, and 24, will include: widespread pain, symptom severity, functional performance, balance, muscle strength and power, psychological functioning, sleep quality, self-efficacy, treatment durability, and health-related quality of life. Ethics and Trial Registration: This study was approved by the Institutional Review Board of Beijing Tiantan Hospital (KY2025-217-03-08) and was registered with ClinicalTrials.gov (NCT07382921). All study procedures will be conducted in accordance with the Declaration of Helsinki (1964) and its subsequent amendments (7th revision, Fortaleza, Brazil, 2013). Conclusion: This trial will provide evidence for the efficacy and safety of pregabalin combined with tizanidine in the treatment of FM. Keywords: fibromyalgia, pregabalin, tizanidine

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Cite This Study

Liu et al. (Fri,) studied this question.

synapsesocial.com/papers/6a080985a487c87a6a40b6d8 https://doi.org/https://doi.org/10.2147/jpr.s605429

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