What are the next steps and monitoring requirements for a patient switching from oral Pre-Exposure Prophylaxis (PrEP) tablets to cabotegravir (Integrase Strand Transfer Inhibitor) injections for Human Immunodeficiency Virus (HIV) prevention?

Switching from Oral PrEP to Cabotegravir Injections for HIV Prevention

For patients switching from oral PrEP tablets to cabotegravir injections, continue the oral PrEP for 7 days after the first cabotegravir injection to ensure continuous protection during the transition period. 1

Initial Steps for Transition

Pre-Injection Assessment

• Confirm HIV-negative status with both:
  • Laboratory-based HIV antigen/antibody test
  • HIV RNA (viral load) test with lower limit of quantification ≤50 copies/mL 2
• If RNA testing is unavailable, proceed with a rapid point-of-care antibody test while awaiting laboratory results 2
• Screen for symptoms of acute HIV infection (fever, rash, lymphadenopathy)
• Ensure no contraindications to cabotegravir

Oral Lead-In Considerations

• An oral cabotegravir lead-in of 4-5 weeks is optional but recommended for:
  • Patients with severe atopic histories
  • Patients who specifically request it 1
• Oral lead-in is NOT recommended for patients who struggle with daily oral medication adherence 1

Injection Schedule and Administration

Initial Dosing

• First injection: Cabotegravir 600 mg (3 mL) via gluteal intramuscular injection
• Second injection: 4 weeks after first injection
• Subsequent injections: Every 8 weeks thereafter 1, 2

Administration Technique

• Administer via gluteal intramuscular injection only
• The ventrogluteal site is recommended 3
• Observe patient for approximately 10 minutes after injection to monitor for post-injection reactions 3

Ensuring Continuous Protection

Overlap Period

• Continue oral PrEP for 7 days after the first cabotegravir injection 1
• For patients transitioning from oral cabotegravir lead-in, continue oral cabotegravir for 7 days after first injection
• For patients transitioning directly from tenofovir-based oral PrEP, continue the oral PrEP for 7 days after first injection 1

Backup Plan

• Provide a 1-month supply of appropriate tenofovir-based oral PrEP for use if injections are delayed by ≥7 days 1, 2
• If injections are resumed ≥8 weeks late, "reloading" is required with two injections 4 weeks apart before returning to the 8-week schedule 2

Monitoring Requirements

Follow-up Testing Schedule

• HIV testing:
  • Rapid point-of-care HIV antibody test on the day of each injection 1
  • Laboratory-based HIV antigen/antibody test at each injection visit 1
• STI screening: Every 4 months (every second injection) 1
• Liver function tests: Every 6 months 1

Side Effects and Management

Common Side Effects

• Injection site reactions (most common):
  • Pain, tenderness, induration, swelling, erythema
  • Usually mild to moderate and diminish in severity over time 2, 4
  • Manage with topical/systemic analgesics and hot/cold packs 1

Serious Adverse Events to Monitor

• Hypersensitivity reactions (rare):
  • Rash, fever, malaise, fatigue, muscle/joint aches
  • Discontinue cabotegravir if suspected 3
• Post-injection reactions (rare):
  • Dyspnea, bronchospasm, agitation, abdominal cramping, dizziness
  • Usually resolve within minutes 3
• Hepatotoxicity:
  • Monitor liver function tests every 6 months 1
• Depressive disorders:
  • Evaluate promptly if symptoms develop 3

Clinical Pearls and Pitfalls

Important Considerations

• Cabotegravir has superior efficacy compared to daily oral PrEP regimens 5, 6
• Cabotegravir has a long half-life (approximately 40 days) 7
• Residual concentrations may remain in circulation for up to 12 months after discontinuation 3

Potential Pitfalls

1. Delayed HIV detection: HIV infection may be more difficult to detect in patients on cabotegravir; use both antibody and RNA testing 6
2. Resistance concerns: If HIV infection occurs while on cabotegravir, integrase inhibitor resistance may develop 6
3. Injection technique: Improper injection technique can lead to post-injection reactions; follow proper administration guidelines 3
4. Missed appointments: Plan for adherence to the injection schedule; provide oral PrEP backup 1

Patient Satisfaction

Despite injection site reactions, studies show high satisfaction rates with cabotegravir injections:

• 75% of participants reported satisfaction with cabotegravir injections
• 79% were willing to continue the therapy
• 87% would recommend the therapy to others 4