What precautions should be taken to minimize the risk of photosensitivity in patients taking Phesgo (pertuzumab and trastuzumab)

Photosensitivity Precautions for Patients Taking Phesgo

Patients taking Phesgo (pertuzumab and trastuzumab) should use broad-spectrum sunscreen with SPF ≥30, wear protective clothing, avoid direct sunlight especially during peak hours (10 AM - 4 PM), and use UV-blocking sunglasses to minimize the risk of photosensitivity reactions.

Understanding Photosensitivity Risk with Phesgo

While the FDA label for Phesgo does not specifically list photosensitivity as a common adverse effect 1, photosensitivity reactions can occur with many medications and should be considered as a potential risk. Photosensitivity reactions can manifest as either phototoxic (more common) or photoallergic reactions that can significantly impact patient quality of life and treatment adherence.

Comprehensive Photosensitivity Prevention Strategy

Sun Protection Measures

• Sunscreen application:

  • Use broad-spectrum sunscreen (protecting against both UVA and UVB) with SPF ≥30
  • Apply 15-30 minutes before sun exposure
  • Reapply every 2 hours when outdoors
  • Ensure adequate coverage (typical application is often only 0.5 mg/cm² instead of the recommended 2 mg/cm²) 2
  • Pay special attention to commonly missed areas: posterior neck, lateral neck, temples, and ears 2

• Protective clothing:

  • Wear wide-brimmed hats
  • Use long-sleeved shirts and long pants
  • Consider UV-protective clothing with UPF rating
  • Use UV-blocking sunglasses to protect eyes 3

Timing and Environmental Considerations

• Avoid sun exposure during peak hours (10 AM - 4 PM) 3
• Seek shade when outdoors
• Be aware that UV exposure can occur through window glass (in cars, buildings) 3
• Consider UV-protective window films for car windows if patient spends significant time driving

Additional Precautions

• Review concomitant medications for potential photosensitizing effects
• Common photosensitizing medications include:
  • Diuretics (especially hydrochlorothiazide)
  • Antibiotics (tetracyclines, fluoroquinolones)
  • NSAIDs
  • Cardiovascular drugs (amiodarone) 4, 5
• Avoid tanning beds and artificial UV light sources 6

Monitoring and Management

Patient Education

• Inform patients about the possibility of photosensitivity reactions
• Teach patients to recognize early signs of photosensitivity:
  • Exaggerated sunburn
  • Skin rash in sun-exposed areas
  • Itching or burning sensation on exposed skin

If Photosensitivity Occurs

• Document the reaction and its relationship to sun exposure
• Consider topical corticosteroids for symptomatic relief 7
• Evaluate whether medication adjustment is necessary
• Increase photoprotection measures

Special Considerations

For Patients with Pre-existing Photosensitivity

• More rigorous photoprotection is required
• Consider vitamin D screening and supplementation 8
• Regular dermatological follow-up may be beneficial

For Patients Requiring Outdoor Activities

• Plan activities for early morning or evening hours
• Use physical barriers (umbrellas, canopies) when outdoors
• Carry pocket-sized sunscreen for reapplication

Conclusion

While Phesgo does not have specific photosensitivity warnings in its FDA label, implementing comprehensive photoprotection measures is prudent to minimize any potential risk. The focus should be on prevention through multiple protective strategies rather than limiting necessary cancer treatment.