The Impact of CYP2D6 Polymorphism on Tramadol Pharmacodynamics

August 26, 2026 updated by: Shaymaa Faruq Hamadameen, Elweyia Maternity Teaching Hospital

The Outcome of CYP2D6 Polymorphism on Tramadol Analgesia in Postpartum Patients in Erbil

CYP2D6 is an enzyme involved in the hepatic metabolism of many clinically important drugs: antiarrhythmics, antidepressants, antipsychotics, β-blockers, and analgesics such as tramadol and codeine. CYP2D6 is highly polymorphic and significant interindividual variability has been observed worldwide. This study aims to investigate the distribution of CYP2D6 polymorphisms among post-cesarean female patients in Erbil city, Iraq. The findings of this study may indicate the presence of CYP2D6 gene variants among the Kurdish female population in Erbil, which could contribute to tramadol analgesic failure or exaggerated adverse effects. This study could also serve as a foundation for further pharmacogenetic research, individualizing treatments and targeting a larger sample size in the future.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Observational

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
40

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

  • Iraq
      • Erbil, Iraq, 40/0112
        • Hawler Medical University/ College 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

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult

Accepts Healthy Volunteers

No

Sampling Method

Non-Probability Sample

Study Population

Pregnant patients who were indicated for elective cesarean section surgery at public hospital (Maternity Teaching hospital) located in Erbil city, Iraq were enrolled.

Description

Inclusion Criteria:

  • Female patients aged between 18-50 years old
  • Patients who are indicated to undergo elective cesarean section surgery
  • Patients that are indicated to receive tramadol drug for postpartum pain management

Exclusion Criteria:

  • Patients with any history of severe renal, liver, respiratory diseases and/or seizures
  • Patients with history of psychiatric disorders or unable to provide consent
  • Patients with complicated surgeries or neonatal distress or unable to perform the clinical assessment of pain
  • Patients with history of consumption of chronic alcohol or opioid or drug abuse
  • Patients with history of known allergy to tramadol

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

Cohorts and Interventions

Group / Cohort

Group / Cohort

A group or subgroup of participants in an observational study that is assessed for biomedical or health outcomes.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
post-cesarean patients
All of these patients were planned to undergo elective cesarean surgery and receive postpartum management for twenty-four hours at the Erbil Maternity and Childbirth Hospital. Consent was taken from each patient prior to the enrollment into the study. Their age ranged between 21-42 years. Patients received one dose of tramadol drug (100mg/2ml of Trodon® Hemofarm) intravenously for management of postpartum pain after gaining back their pain sensation.
Drug: Trodon® Hemofarm
Consent was taken from each patient prior to the enrollment into the study during the first interview and 2 ml of blood was withdrawal for the CYP2D6 genotyping. After the cesarean section surgery, each patient received one dose of 100mg/2ml Trodon® Hemofarm for treating the postpartum pain and the patients were monitored for 24 hours. Follow-up was performed for each enrolled patient in which the VAS score, blood pressure, heart rate, oxygen saturation and any new effects after 1 hour, 6 hours of tramadol administration were recorded. In addition, after 24 hours evaluations for nocturnal pain, dietary state and bowel movement were performed.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Visual analog scale (10 cm)
Time Frame: after 1 hour and 6 hours of receiving single dose of tramadol
Visual analog scale is used for measuring pain intensity on a scale of 0 to 10, in which a score on the line is marked by each patient ranging from "no pain" to "worst pain". The pain intensity increases as the score on the scale goes up.
after 1 hour and 6 hours of receiving single dose of tramadol

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Blood pressure (mm of Hg)
Time Frame: after 1 hour and 6 hours of receiving single dose of tramadol
Blood pressure was measured by automatic blood pressure monitor (mm of Hg) after 1 hour and 6 hours of IV tramadol administration to detect any change in the blood pressure of each patient.
after 1 hour and 6 hours of receiving single dose of tramadol
Heart rate (beats per minute)
Time Frame: after 1 hour and 6 hours of receiving single dose of tramadol
Pulse was recorded by pulse oximetry (beats per minute) after 1 hour and 6 hours of IV tramadol administration to detect any change in the heart rate of each patient.
after 1 hour and 6 hours of receiving single dose of tramadol
Oxygen saturation (SPO2%)
Time Frame: after 1 hour and 6 hours of receiving single dose of tramadol
Oximetry was used (SPO2 %) for evaluating the oxygen saturation of each patient.
after 1 hour and 6 hours of receiving single dose of tramadol
Nocturnal pain
Time Frame: after 24 hours of receiving single dose of tramadol
Evaluation of nocturnal pain was performed for each patient by a questionnaire after 24 hours to determine pain at night and whether it has impacted on the sleeping quality of the patient.
after 24 hours of receiving single dose of tramadol
Dietary state
Time Frame: after 24 hours of receiving single dose of tramadol
Evaluation of dietary state was performed for each patient, in which the patient was asked after 24 hours to determine whether they have taken anything within the last 24 hours and if yes did they take liquid and/or solid food.
after 24 hours of receiving single dose of tramadol
Adverse effects
Time Frame: after 1 hour and 6 hours of receiving single dose of tramadol for recording any adverse effects, and after 24 hours of receiving single dose of tramadol for evaluation of the bowel movement (whether the patient was constipated).
A questionnaire was presented to each patient for recording any newly appearing effects that are noticed by the patient after 1 hour and 6 hours of receiving single dose of tramadol drug intravenously. In addition, the patient was asked after 24 hours whether they had had bowel movement within the last 24 hours (whether the patient was constipated).
after 1 hour and 6 hours of receiving single dose of tramadol for recording any adverse effects, and after 24 hours of receiving single dose of tramadol for evaluation of the bowel movement (whether the patient was constipated).

Collaborators and Investigators

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

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Elweyia Maternity Teaching 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

  • https://doi.org/10.3897/pharmacia.72.e162100

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)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
September 22, 2024

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
February 23, 2025

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
April 30, 2025

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
January 28, 2025

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
February 5, 2025

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
February 7, 2025

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
August 28, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
August 26, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
August 1, 2026

More Information

Terms related to this study

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • ElweyiaMTH

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

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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