Tamoxifen in Women With Breast Cancer and in Women at High-Risk of Breast Cancer Who Are Receiving Venlafaxine, Citalopram, Escitalopram, Gabapentin, or Sertraline

• Status: Active, not recruiting
• Trial end date: 2021-12-15
• Target enrollment: 0
• Participant gender: All

Summary

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.

• Accepts Healthy Volunteers?: No

Details

• Lead Sponsor: Mayo Clinic
• Collaborator: National Cancer Institute (NCI)
• Treatments: Citalopram; Dexetimide; Gabapentin; gamma-Aminobutyric Acid; Sertraline; Tamoxifen; Venlafaxine Hydrochloride

Criteria

DISEASE CHARACTERISTICS:

• Meets 1 of the following criteria:

• Diagnosis of invasive or non-invasive breast cancer

• At high risk for developing breast cancer

• Has been receiving tamoxifen citrate for at least 4 weeks without any breaks either for the prevention or the adjuvant treatment of invasive or non-invasive breast cancer at a dose of 20 mg/day

• Planning to begin medical therapy with one of the following drugs, as determined by physician:

• Venlafaxine

• Citalopram hydrobromide

• Escitalopram oxalate

• Sertraline hydrochloride

• Gabapentin

• Agrees to continue tamoxifen citrate during the proposed minimum study period of 8 weeks

• Known CYP2D6 genotype

• Not known to be a CYP2D6 poor metabolizer (defined as homozygous for one of the following CYP2D6 null alleles: *3, *4, *5, *6) as determined from the baseline genotype test

• Estrogen receptor-positive disease (for patients with breast cancer)

PATIENT CHARACTERISTICS:

• Menopausal status not specified

• Life expectancy ≥ 16 weeks

• Willing to return to primary site of enrollment for follow-up, including any of the following:

• Mayo Clinic Rochester

• Indiana University

• University of Michigan

• Johns Hopkins

• Fairfax-Northern Virginia Hematology-Oncology, PC

• No contraindication for venlafaxine, citalopram hydrobromide, escitalopram oxalate, gabapentin, or sertraline hydrochloride

PRIOR CONCURRENT THERAPY:

• See Disease Characteristics

• More than 4 weeks since prior and no concurrent medications that are known to inhibit the CYP2D6 system