Alternative vs. Once-Daily Oral Iron Supplementation in Iron Deficiency Anemia (IDA)

January 5, 2026 updated by: Phramongkutklao College of Medicine and Hospital

Alternative vs. Once-Daily Oral Iron Supplementation in Iron Deficiency Anemia (IDA): A Multicenter, Randomized, Open-Label, Non-Inferiority Trial

The goal of this clinical trial is to compare the effectiveness and tolerability of two different oral iron regimens in adults with iron deficiency anemia (IDA). The main questions it aims to answer are:

Is alternate-day oral iron supplementation as effective as once-daily dosing in improving hemoglobin levels?

What are the side effects associated with each dosing regimen?

Researchers will compare once-daily vs. alternate-day oral ferrous fumarate to evaluate whether alternate-day dosing is non-inferior in terms of hematologic response, with fewer adverse effects.

Participants will:

Be randomly assigned to take ferrous fumarate 200 mg once daily or 400 mg on alternate days for 8 weeks

Undergo blood tests and clinical assessments at baseline, Week 4, and Week 8

Report any side effects and bring remaining pills to evaluate medication adherence

This is a multicenter, randomized, open-label, non-inferiority trial conducted in adults aged 20 years or older with IDA.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

114

Phase

  • Not Applicable

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 Backup

Study Locations

  • Thailand
      • Bangkok, Thailand, 10400
        • Recruiting
        • Phramongkutklao Hospital
        • Contact:
        • Contact:
        • Principal Investigator:
          • Aticha Kraiput, Doctor of Medicine
        • Sub-Investigator:
          • Tanapun Thamgrang, Doctor of Medicine

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

Description

Inclusion Criteria:

  • Male or female patients aged ≥20 years diagnosed with iron deficiency anemia, defined as: hemoglobin (Hb) <13 g/dL in males or <12 g/dL in females, and ferritin <50 ng/mL or transferrin saturation (TSAT) <20%.
  • No iron supplementation within the past 3 months.

Exclusion Criteria:

  • Hemodynamic instability (e.g., acute bleeding or hypotension).
  • Severe heart failure (New York Heart Association [NYHA] Class III-IV) or other active cardiac diseases.
  • Active malignancy or history of cancer within the past 3 years (except non-melanoma skin cancer).
  • Pregnancy or breastfeeding.
  • Chronic liver disease including cirrhosis (Child-Pugh class B or C).
  • Chronic kidney disease (estimated glomerular filtration rate [eGFR] <60 mL/min/1.73 m²).
  • Clinically significant thalassemia or hemoglobinopathies.
  • Ongoing infection or chronic inflammatory diseases (e.g., rheumatoid arthritis, inflammatory bowel disease).
  • Malabsorption disorders (e.g., history of bariatric surgery).
  • Red blood cell transfusion within the past 3 months.

Withdrawal Criteria

  • Withdrawal of informed consent.
  • Severe adverse events requiring permanent discontinuation of study medication.
  • Investigator's judgment that continued participation poses a safety risk.
  • Non-adherence to study medication (compliance < 75%).

Treatment Failure

- Increase in hemoglobin level of < 1 g/dL at Week 4 or Week 8 compared with baseline.

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: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Active Comparator: Once-Daily Dosing Group
Participants will receive ferrous fumarate 200 mg, taken orally once daily for 8 weeks. This arm represents the standard dosing regimen for treating iron deficiency anemia (IDA). Participants will be monitored at baseline, Week 4, and Week 8 for blood counts, iron parameters, and adverse effects. Medication adherence will be assessed using pill counts.
Drug: Ferrous Fumarate Oral Tablet
Ferrous fumarate oral tablet 200 mg is an iron supplement used for the treatment of iron deficiency anemia (IDA). In this study, it is administered as either one tablet daily (OD group) or two tablets on alternate days (AD group), with a treatment duration of 8 weeks. The goal is to compare the efficacy and tolerability of alternate-day dosing versus standard once-daily dosing.
Other Names:
  • Ferrous Fumarate 200 mg tablet
  • Oral iron supplement
Experimental: Alternate-Day Dosing Group
Participants will receive ferrous fumarate 400 mg (two 200 mg tablets), taken orally on alternate days for 8 weeks. This dosing strategy is being evaluated for improved iron absorption and fewer gastrointestinal side effects compared to daily dosing. Participants will be monitored at baseline, Week 4, and Week 8 for blood counts, iron parameters, and adverse effects. Medication adherence will be assessed using pill counts.
Drug: Ferrous Fumarate Oral Tablet
Ferrous fumarate oral tablet 200 mg is an iron supplement used for the treatment of iron deficiency anemia (IDA). In this study, it is administered as either one tablet daily (OD group) or two tablets on alternate days (AD group), with a treatment duration of 8 weeks. The goal is to compare the efficacy and tolerability of alternate-day dosing versus standard once-daily dosing.
Other Names:
  • Ferrous Fumarate 200 mg tablet
  • Oral iron supplement

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Hemoglobin Level at Week 8 After Oral Iron Supplementation
Time Frame: 8 weeks
Hemoglobin concentration (g/dL) measured at Week 8 following oral ferrous fumarate supplementation. Participants are stratified by sex and baseline Hb level. Comparison between once-daily and alternate-day dosing groups will be analyzed using a linear mixed-effects model.
8 weeks

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in Reticulocyte Count at Weeks 4 and 8
Time Frame: 4 and 8 weeks
Mean change in reticulocyte count (%) from baseline to Week 4 and Week 8.
4 and 8 weeks
Change in Serum Ferritin at Weeks 4 and 8
Time Frame: 4 and 8 weeks
Mean change in serum ferritin concentration (ng/mL) from baseline to Week 4 and Week 8.
4 and 8 weeks
Adverse Effects of Ferrous Fumarate
Time Frame: During the 8-week treatment period
Incidence and type of adverse effects experienced by participants during treatment with ferrous fumarate oral tablets.
During the 8-week treatment period

Collaborators and Investigators

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

Sponsor

Phramongkutklao College of Medicine and Hospital

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 9, 2025

Primary Completion (Estimated)

December 31, 2027

Study Completion (Estimated)

December 31, 2027

Study Registration Dates

First Submitted

June 1, 2025

First Submitted That Met QC Criteria

June 10, 2025

First Posted (Actual)

June 11, 2025

Study Record Updates

Last Update Posted (Actual)

January 7, 2026

Last Update Submitted That Met QC Criteria

January 5, 2026

Last Verified

January 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • Hemato-001

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

Individual participant data (IPD) will not be shared due to institutional policy and privacy concerns. Only aggregate data may be shared upon reasonable request.

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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