Should tamoxifen (selective estrogen receptor modulator) be held in a hospitalized patient?

Management of Tamoxifen in Hospitalized Patients

Tamoxifen should NOT be routinely held during hospitalization unless there are specific contraindications such as planned surgery, immobilization, or history of thromboembolic events.

Risk Assessment for Continuing Tamoxifen During Hospitalization

Tamoxifen is a selective estrogen receptor modulator (SERM) used in the treatment of hormone receptor-positive breast cancer. When considering whether to continue or hold tamoxifen during hospitalization, the following factors should be evaluated:

Thromboembolic Risk

• Tamoxifen increases the risk of thromboembolic events 1:
  • Deep vein thrombosis (DVT)
  • Pulmonary embolism (PE)
  • Stroke
  • Transient ischemic attack (TIA)

Decision Algorithm

1. Hold tamoxifen if the patient has:

   • Planned surgery (resume postoperatively when normal ambulation is achieved) 1
   • Prolonged immobilization
   • Active thromboembolic event
   • History of DVT, PE, stroke, or TIA (absolute contraindications) 1

2. Continue tamoxifen if:

   • Patient is ambulatory
   • No acute thromboembolic risk factors
   • No contraindications present

Benefits of Continuing Tamoxifen

Maintaining tamoxifen therapy is important for several reasons:

• Reduces risk of breast cancer recurrence 2
• Provides ongoing protection against contralateral breast cancer 3
• Avoids disruption in treatment schedule that could impact long-term efficacy
• Prevents potential withdrawal effects

Risks of Interrupting Tamoxifen

Interrupting tamoxifen therapy may have consequences:

• Potential reduction in efficacy if interruptions are frequent or prolonged
• Poor adherence to tamoxifen is associated with worse outcomes 2
• Approximately 22-32% of patients discontinue tamoxifen within the first 1-2 years of treatment 2

Special Considerations

Medication Interactions

• Avoid strong CYP2D6 inhibitors (paroxetine, fluoxetine, bupropion) as they can reduce tamoxifen efficacy 2, 1
• If antidepressants are needed, prefer mild CYP2D6 inhibitors (citalopram, escitalopram, venlafaxine) 1

Monitoring During Hospitalization

• If continuing tamoxifen, implement appropriate VTE prophylaxis according to hospital protocols
• Monitor for signs of thromboembolic complications
• Assess for any new medication interactions with tamoxifen

Resuming Tamoxifen After Temporary Discontinuation

If tamoxifen was temporarily held during hospitalization:

• Resume as soon as the contraindication resolves
• Ensure patient understands the importance of continuing therapy for the prescribed duration (typically 5 years) 2, 1
• Document the interruption and plan for resumption in discharge instructions

Communication with Outpatient Providers

• Clearly document any changes to tamoxifen therapy in the discharge summary
• Ensure follow-up with the patient's oncologist regarding any interruptions in therapy
• Communicate any concerns about tamoxifen therapy to the outpatient provider

Remember that the benefits of tamoxifen in reducing breast cancer recurrence and mortality outweigh the risks in most patients, and unnecessary interruptions should be avoided whenever possible.