What monitoring is required for individuals taking Truvada (emtricitabine and tenofovir disoproxil fumarate) for Pre-Exposure Prophylaxis (PrEP)?

Truvada PrEP Monitoring Requirements

Individuals on Truvada PrEP require HIV testing every 3 months, STI screening every 3 months, renal function monitoring every 6 months (or more frequently if risk factors present), and hepatitis B/C surveillance at baseline and periodically thereafter. 1

Pre-Initiation Testing (Mandatory Before Starting)

Before prescribing Truvada PrEP, you must obtain:

• HIV testing with combination antigen-antibody assay (fourth generation preferred); add HIV RNA testing if acute HIV infection is suspected based on symptoms or recent high-risk exposure 1
• Serum creatinine and calculated creatinine clearance using Cockcroft-Gault formula—do NOT start if creatinine clearance is <60 mL/min 1
• Hepatitis B surface antigen (HBsAg) testing 1
• Hepatitis C antibody testing 1
• STI screening at all potentially exposed anatomic sites (oral, rectal, urogenital) for gonorrhea, chlamydia, and syphilis 1
• Pregnancy test for women of childbearing potential 1

Critical pitfall: Do not delay PrEP initiation while waiting for creatinine or HBsAg results if the patient is at immediate high risk, but ensure these tests are drawn before the first dose. 1

Ongoing Monitoring Schedule

Every 3 Months (Quarterly Visits)

• HIV testing with combination antigen-antibody assay—PrEP prescription should NOT exceed 90 days without interval HIV testing 1
• STI screening at all exposed anatomic sites (rectal, pharyngeal, urogenital) for gonorrhea and chlamydia by nucleic acid amplification testing (NAAT), plus syphilis serology 1
• Adherence assessment and counseling at every visit 1
• Risk behavior assessment and provision of condoms 1
• Pregnancy testing for women at each visit 1

Every 6 Months

• Serum creatinine and estimated glomerular filtration rate (eGFR) calculation 1
• Hepatitis C serologic testing (at minimum annually, but every 6 months is reasonable for high-risk individuals) 1

Enhanced Renal Monitoring (Every 3 Months or More Frequently)

More frequent creatinine monitoring is required for patients with:

• Age >50 years 1
• Taking hypertension or diabetes medications 1
• Baseline eGFR <90 mL/min 1
• Other renal risk factors 1

Important consideration: The DISCOVER trial demonstrated that TDF/FTC causes measurable declines in eGFR (approximately 4%) and increases in proximal tubular injury biomarkers within 6 months, making renal monitoring essential. 2

Special Monitoring Considerations

Hepatitis B Co-infection

• If HBsAg is positive at baseline, TDF/FTC can serve dual purposes as both PrEP and hepatitis B treatment 1
• Critical warning: Discontinuing TDF/FTC in patients with active hepatitis B can cause acute hepatitis flares or hepatic decompensation, particularly in those with cirrhosis—careful monitoring of liver function is mandatory after discontinuation 1

First Follow-Up Visit (30 Days After Initiation)

• A visit at 30 days after PrEP start is recommended specifically to assess for adverse effects, perform follow-up HIV testing, and support adherence 1

Weight Monitoring

• Monitor weight at follow-up visits, as emtricitabine/tenofovir alafenamide (if used instead of TDF/FTC) is associated with greater weight gain (median 1.7 kg vs 0.5 kg at 96 weeks) 3

If HIV Infection Occurs During PrEP

• Immediately add a boosted protease inhibitor (darunavir/ritonavir or darunavir/cobicistat) and/or dolutegravir to TDF/FTC while awaiting HIV RNA and resistance testing results 1
• Order resistance testing and establish linkage to HIV care 1
• Switch to a recommended initial antiretroviral treatment regimen once HIV is confirmed 1

Common Pitfalls to Avoid

• Do not prescribe >90-day supplies without documented negative HIV testing 1
• Do not use TDF-based PrEP if creatinine clearance is <60 mL/min—this is an absolute contraindication 1, 4
• Do not forget three-site STI screening for men who have sex with men (rectal, pharyngeal, urogenital)—single-site testing misses most infections 5
• Do not discontinue monitoring even if the patient reports consistent condom use—STI rates remain high (21-28 cases per 100 person-years) even among PrEP users 3