Clinical trial · Observational
Tamoxifen in Women With Breast Cancer and in Women at High-Risk of Breast Cancer Who Are Receiving Venlafaxine, Citalopram, Escitalopram, Gabapentin, or Sertraline
The Effect of Antidepressants and Gabapentin on Tamoxifen Pharmacokinetics: A Prospective Study
- Source
- ClinicalTrials.gov
- Retrieved
- Sep 8, 2026
- Layer
- normalized (units and labels harmonized; values unchanged)
- Run
- ING-CLINICALTRIALS-20260908-000001
Summary
Brief summary (as posted)
RATIONALE: Studying samples of blood in the laboratory from patients receiving tamoxifen may help doctors learn more about the effects of other drugs on the level of tamoxifen in the blood. PURPOSE: This clinical trial is studying levels of tamoxifen in the blood of women with breast cancer and in women at high risk of breast cancer who are receiving tamoxifen together with venlafaxine, citalopram, escitalopram, gabapentin, or sertraline.
Conditions
Conditions (4)
Free-text conditions as registered, with the CancerIndex entity they were reconciled to and the match type.
| Condition (as posted) | Mapped entity | Match | Confidence |
|---|---|---|---|
| Breast Cancer | Malignant Breast Neoplasm | CURATED_EXACT | 0.92 |
| Depression | — | UNRESOLVED | — |
| Hot Flashes | — | UNRESOLVED | — |
| Psychosocial Effects of Cancer and Its Treatment | — | UNRESOLVED | — |
Interventions
Interventions (11)
| Intervention | Type | Mapped drug | Match |
|---|---|---|---|
| adjuvant therapy | Procedure | — | UNRESOLVED |
| citalopram hydrobromide | Drug | — | UNRESOLVED |
| escitalopram oxalate | Drug | — | UNRESOLVED |
| gabapentin | Drug | — | UNRESOLVED |
| high performance liquid chromatography | Other | — | UNRESOLVED |
| laboratory biomarker analysis | Other | — | UNRESOLVED |
| molecular genetic technique | Genetic | — | UNRESOLVED |
| pharmacological study | Other | — | UNRESOLVED |
| sertraline hydrochloride |
Design
Arms and outcomes
Arms (0)
[]Primary outcomes (1)
- measure
- Percent change in plasma concentrations of 4-hydroxy tamoxifen and of endoxifen after ≥ 8 weeks of concurrent administration of tamoxifen citrate and a CYP2D6 inhibitor
- timeFrame
- Between 8-16 weeks
Eligibility
Eligibility (as posted)
- Sex
- All
- Minimum age
- 18 Years
- Maximum age
- 120 Years
Show eligibility criteria text
Inclusion Criteria: * Prescribed tamoxifen either for the prevention or treatment of non-invasive or invasive breast cancer. * Tamoxifen use \> 4 weeks without any breaks at a dose of 20 mg/day prior to registration * to begin medical therapy with one of the following drugs: venlafaxine, citalopram, escitalopram, sertraline or gabapentin as determined by their physician * Agree to continue tamoxifen during the proposed minimum study period of 8 weeks * Willing to avoid known inhibitors of the CYP2D6 system for duration of study * Ability to provide informed consent * Willing to return to primary site of enrollment for follow-up * Life expectancy \>= 16 weeks * Agree to provide a blood specimen at the time of pre-treatment (baseline) and at follow-up Exclusion Criteria: * Contraindication to the use of venlafaxine, citalopram, escitalopram, gabapentin or sertraline. * Use of medications that are known to inhibit the CYP2D6 system within 3 weeks of registration. (see appendix II for list) * Known to be a CYP2D6 poor metabolizer (defined as homozygous for one of the following CYP2D6 null alleles: \*3, \*4, \*5, \*6). * Note: CYP2D6 genotyping is not required prior to enrollment; however, CYP2D6 genotyping will be performed at baseline and the treating physician will be notified of the results: all genotypic CYP2D6 PM will be replaced
References
Publications (0)
Data not yet available