Pre- and Post-Treatment Investigation of B12 and Folic Acid (Folate) Levels in Patients Receiving Antiepileptic (Anticonvulsant) Treatment for Fibromyalgia: Retrospective Study

January 23, 2026 updated by: Gaziosmanpasa Research and Education Hospital

Fibromyalgia is a rheumatological disorder characterised by chronic widespread body pain, second most common after osteoarthritis. The overall prevalence is 2-8% and it is more common in women. Diffuse body pain, fatigue, sleep and cognitive dysfunction occur. The etiology of fibromyalgia is multifactorial and occurs due to central and peripheral pain mechanisms that occur with neuroendocrine imbalance due to psychological and physical stress in people with genetic predisposition. The diagnostic criteria for fibromyalgia were updated by the American College of Rheumatology in 2016 to include a widespread body pain scale and a symptom severity scale.

Fibromyalgia treatment consists of drug (antidepressants and antiepileptics) and non-drug treatments. Pregabalin is also used in the treatment of epilepsy by blocking and modulating the α2 δ subunit of voltage-dependent calcium channels. There are studies showing that antiepileptics cause folate and vitamin B12 deficiency in epilepsy patients. In our study, we aimed to retrospectively investigate vitamin B12 and folic acid levels before and after treatment in patients with fibromyalgia using antiepileptics (anticonvulsants).

Study Overview

Status

Completed

Conditions

Detailed Description

After the acceptance of the study (after obtaining ethics committee approval), patients who have been followed up for at least 6 months in the physical medicine and rehabilitation outpatient clinic with a diagnosis of fibromyalgia and who use pregabalin will be evaluated retrospectively (1-year records). Blood vitamin B12 and folate (folic acid) levels of the patients before and after antiepileptics (anticonvulsants). use will be determined. Patients will be evaluated whether there is a change in vitamin B12 and folic acid levels due to antiepileptics (anticonvulsants) drug use.

Study Type

Observational

Enrollment (Actual)

104

Contacts and Locations

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

Study Locations

  • Turkey (Türkiye)
    • Gaziosmanpasa
      • Istanbul, Gaziosmanpasa, Turkey (Türkiye), 34255
        • Gaziosmanpasa Research and Education Hospital

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

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Sampling Method

Non-Probability Sample

Study Population

Patients who were followed up for 6 months in the physical medicine and rehabilitation clinic with a diagnosis of fibromyalgia and who used antiepileptic (anticonvulsant) drugs will be retrospectively evaluated for the 6 months period (June-December 2024) before the ethics committee approval was obtained. Blood vitamin B12 and folate (folic acid) levels of the patients before and after antiepileptic drug use will be determined. Patients will be evaluated whether there is a change in vitamin B12 and folic acid levels depending on drug use.

Description

Inclusion Criteria:

  • Patients aged 18-75 years who have been diagnosed with fibromyalgia, whose vitamin B12 and folic acid levels have been analysed, who do not receive vitamin B12 and folic acid treatment, and who do not have diabetes mellitus, liver and kidney failure

Exclusion Criteria:

  • Patients receiving vitamin B12 and folic acid therapy at the time of antiepileptic (anticonvulsant) drugs initiation, patients with hepatic and renal insufficiency

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

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Vitamin B12 level analysed before treatment (pre-treatment) (retrospective)
Time Frame: Within 1 month
Vitamin B12 level (pg/mL) among the laboratory parameters analysed before antiepileptic treatment (pre-treatment) for fibromyalgia will be screened retrospectively. Patients who applied to the physical medicine and rehabilitation clinic with a diagnosis of fibromyalgia in the last 6 months (June-December 2024) before the ethics committee application date, who were followed up with this diagnosis and started antiepileptic treatment will be screened within 1 month.
Within 1 month
Vitamin B12 level analysed after treatment (post-treatment) (retrospective)
Time Frame: Within 1 month
Vitamin B12 level (pg/mL) among the laboratory parameters analysed after antiepileptic treatment (post-treatment) for fibromyalgia will be screened retrospectively. Patients who applied to the physical medicine and rehabilitation clinic with a diagnosis of fibromyalgia in the last 6 months (June-December 2024) before the ethics committee application date, who were followed up with this diagnosis and started antiepileptic treatment will be screened within 1 month.
Within 1 month
Folic acid level analysed before treatment (pre-treatment) (retrospective)
Time Frame: Within 1 month
Folic acid level (ng/mL), one of the laboratory parameters analysed before antiepileptic treatment for fibromyalgia (pre-treatment), will be screened retrospectively. Patients who applied to the physical medicine and rehabilitation clinic with a diagnosis of fibromyalgia in the last 6 months (June-December 2024) before the ethics committee application date, who were followed up with this diagnosis and started antiepileptic treatment will be screened within 1 month.
Within 1 month
Folic acid level analysed after treatment (post-treatment) (retrospective)
Time Frame: Within 1 month
Folic acid level (ng/mL), one of the laboratory parameters analysed after antiepileptic treatment for fibromyalgia (post-treatment), will be screened retrospectively. Patients who applied to the physical medicine and rehabilitation clinic with a diagnosis of fibromyalgia in the last 6 months (June-December 2024) before the ethics committee application date, who were followed up with this diagnosis and started antiepileptic treatment will be screened within 1 month.
Within 1 month

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
25-OH Vitamin D level analysed before treatment (pre-treatment) (retrospective)
Time Frame: Within 1 month
D vitamini (25-OH Vitamin D) (ng/mL) among the laboratory parameters analysed before antiepileptic treatment (pre-treatment) for fibromyalgia will be screened retrospectively. Patients who applied to the physical medicine and rehabilitation clinic with a diagnosis of fibromyalgia in the last 6 months (June-December 2024) before the ethics committee application date, who were followed up with this diagnosis and started antiepileptic treatment will be screened within 1 month.
Within 1 month
25-OH Vitamin D level analysed after treatment (post-treatment) (retrospective)
Time Frame: Within 1 month
25-OH Vitamin D (ng/mL) among the laboratory parameters analysed after antiepileptic treatment (post-treatment) for fibromyalgia will be screened retrospectively. Patients who applied to the physical medicine and rehabilitation clinic with a diagnosis of fibromyalgia in the last 6 months (June-December 2024) before the ethics committee application date, who were followed up with this diagnosis and started antiepileptic treatment will be screened within 1 month.
Within 1 month

Collaborators and Investigators

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

Sponsor

Gaziosmanpasa Research and Education 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 (Actual)

June 11, 2025

Primary Completion (Actual)

June 25, 2025

Study Completion (Actual)

July 1, 2025

Study Registration Dates

First Submitted

May 21, 2025

First Submitted That Met QC Criteria

June 5, 2025

First Posted (Actual)

June 10, 2025

Study Record Updates

Last Update Posted (Actual)

January 26, 2026

Last Update Submitted That Met QC Criteria

January 23, 2026

Last Verified

May 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 03

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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