Study Protocol: Impact of Metamizole (Optalgin®) on Anti-Xa Concentrations in Oncology Patients Receiving DOACs

January 26, 2026 updated by: Rambam Health Care Campus

Impact of Metamizole (Optalgin®) on Anti-Xa Concentrations in Oncology Patients Receiving DOACs

Evaluation of the Effect of metamizole (Optalgin®) on Anti-Xa Levels in Oncology Patients Receiving Direct Oral Anticoagulants (DOACs)

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Detailed Description

Evaluation of the Effect of metamizole (Optalgin®) on Anti-Xa Levels in Oncology Patients Receiving Direct Oral Anticoagulants (DOACs)

Study Type

Interventional

Enrollment (Estimated)

30

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 Locations

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:

  • Adult oncology patients (≥18 years old).
  • Receiving apixaban or rivaroxaban for anticoagulation.
  • New/current metamizole users taking at least 1g TID for pain management.
  • Platelets ≥100×10⁹/L
  • ECOG PS<3
  • Provided informed consent

Exclusion Criteria:

  • History of allergic reaction to metamizole or DOACs.
  • Individuals with significant gastrointestinal disorders that may affect absorption, including (but not limited to) diagnosed bowel obstruction, persistent diarrhea, or the presence of a nasogastric tube (NGT/zonda)

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: Other
  • Allocation: Non-Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Cohort 1: Chronic metamizole users
Patients receiving Optalgin prior to study enrollment
Drug: metamizole
chronic metamizole use
Other Names:
  • OPTALGIN
Drug: metamizole
New metamizole users
Experimental: Cohort 2: New metamizole users
Patients receiving Optalgin after to study enrollment
Drug: metamizole
chronic metamizole use
Other Names:
  • OPTALGIN
Drug: metamizole
New metamizole users

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in DOAC
Time Frame: 1- Baseline 2- End Of Treatment 3- Day 3 Post treatment 4- Day 5 Post Treatment 5- Day 7 Post treatment
Change in DOAC peak and trough concentrations during periods with and without metamizole comedication (5 different time points).
1- Baseline 2- End Of Treatment 3- Day 3 Post treatment 4- Day 5 Post Treatment 5- Day 7 Post treatment

Collaborators and Investigators

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

Sponsor

Rambam Health Care Campus

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)

November 1, 2025

Primary Completion (Estimated)

December 31, 2027

Study Completion (Estimated)

December 31, 2027

Study Registration Dates

First Submitted

September 25, 2025

First Submitted That Met QC Criteria

January 26, 2026

First Posted (Actual)

February 3, 2026

Study Record Updates

Last Update Posted (Actual)

February 3, 2026

Last Update Submitted That Met QC Criteria

January 26, 2026

Last Verified

December 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 0268-25-RMB

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

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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