What are the guidelines for managing a patient on Truvada (emtricitabine and tenofovir disoproxil fumarate)?

Guidelines for Managing a Patient on Truvada

Pre-Initiation Requirements

Before prescribing Truvada, you must document a negative HIV antibody test immediately and confirm creatinine clearance is ≥60 mL/min using the Cockcroft-Gault formula. 1

Mandatory Baseline Testing

• HIV testing: Combined HIV antibody/antigen test (fourth generation preferred); if acute HIV infection is suspected (symptoms or unprotected sex with HIV-positive partner in preceding month), add HIV RNA testing 1, 2
• Renal function: Serum creatinine and calculated creatinine clearance—do not initiate if <60 mL/min 1, 2
• Hepatitis B surface antigen (HBsAg): Screen for active hepatitis B infection; vaccinate if susceptible 1, 2
• Hepatitis C antibody 1, 2
• STI screening: Test for gonorrhea, chlamydia, and syphilis at all potentially exposed anatomic sites (oral, rectal, urogenital for MSM) 1, 2
• Pregnancy test for women: Document negative result or discuss use during pregnancy if positive 1

Critical Contraindications

• Do not prescribe if creatinine clearance <60 mL/min 1, 2
• Do not prescribe to patients with undiagnosed HIV infection 1
• Do not prescribe to women who are breastfeeding 1

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Dosing Regimen

Prescribe tenofovir disoproxil fumarate 300 mg plus emtricitabine 200 mg (one Truvada tablet) once daily. 1, 3

Dosing Considerations by Population

• For MSM: Consider a double loading dose on day 1 to achieve maximal protection within 24 hours, then continue once daily 3
• Event-driven "2-1-1" dosing for MSM: 2 tablets 2-24 hours before sex, then 1 tablet 24 hours later, and 1 tablet 24 hours after that 3
• For heterosexually active adults: One tablet daily; allow 1-week lead-in period before adequate tissue levels are achieved 1, 2
• Prescribe no more than 90-day supply: Renewable only after HIV testing confirms patient remains HIV-uninfected 1

Alternative Formulation (Descovy)

• For MSM with renal impairment (CrCl 30-60 mL/min) or osteopenia/osteoporosis: Switch to emtricitabine 200 mg/tenofovir alafenamide 25 mg (Descovy) once daily 4, 2, 3
• Critical limitation: Descovy is NOT recommended for cisgender women or event-driven dosing 4, 2

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Ongoing Monitoring Schedule

Every 2-3 Months

• HIV testing: Perform HIV antibody test (or fourth generation antibody/antigen test) and document negative result 1, 2
• Pregnancy testing for women: Conduct pregnancy test and document results; if pregnant, discuss continued use with patient and prenatal-care provider 1
• Adherence assessment: Evaluate and support medication adherence at each visit, more often if inconsistent adherence is identified 1, 2
• Risk behavior assessment: Assess risk behaviors, provide risk-reduction counseling and condoms 1, 2
• STI symptom screening: If symptoms present, test and treat as needed 1

Every 3 Months (Quarterly)

• Three-site STI screening for MSM: Test rectal, pharyngeal, and urogenital sites for gonorrhea and chlamydia by NAAT, even if asymptomatic 2

Every 6 Months

• Bacterial STI testing: Test for bacterial STIs even if asymptomatic, and treat as needed 1
• Renal function monitoring: Check serum creatinine and calculate creatinine clearance 1, 2

Renal Monitoring Frequency Adjustments

• More frequent monitoring (every 3-6 months): For patients >50 years, taking hypertension/diabetes medications, or with baseline eGFR <90 mL/min 2
• Initial renal check: At 3 months after initiation, then every 6 months while on PrEP 1

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Dose Adjustments for Renal Impairment

Emtricitabine Dosing

• CrCl ≥50 mL/min: No adjustment 1
• CrCl 30-49 mL/min: 200 mg every 48 hours 1
• CrCl 15-29 mL/min: 200 mg every 72 hours 1
• CrCl <15 mL/min or hemodialysis: 200 mg every 96 hours 1

Tenofovir Disoproxil Fumarate Dosing

• CrCl ≥50 mL/min: No adjustment 1
• CrCl 30-49 mL/min: 300 mg every 48 hours 1
• CrCl 10-29 mL/min: 300 mg every 72-96 hours 1
• Hemodialysis: 300 mg every 7 days 1

Combination Tablet (Truvada)

• CrCl ≥50 mL/min: No adjustment 1
• CrCl 30-49 mL/min: One tablet every 48 hours 1
• CrCl <30 mL/min: Should not use combination tablet; dose individual components separately 1

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Discontinuing Truvada

When to Discontinue

• At patient request 1
• For safety concerns 1
• If HIV infection is acquired 1

Actions Upon Discontinuation

• Perform HIV testing: Confirm whether HIV infection has occurred 1
• If HIV-positive: Order and document resistance testing results, establish linkage to HIV care 1, 2
• If HIV-negative: Establish linkage to risk reduction support services as indicated 1
• Continue for 1 week after last sexual exposure when discontinuing in HIV-negative patients 2

Critical Hepatitis B Considerations

• If active hepatitis B diagnosed at PrEP initiation: Consider appropriate medication for continued treatment of hepatitis B infection upon discontinuation 1
• Risk of severe hepatitis flare: Patients with chronic HBV who discontinue tenofovir are at risk for acute flares or hepatic decompensation, particularly with cirrhosis 2, 3
• If switching HIV regimens in HBV co-infected patients: Must continue tenofovir (TAF or TDF) to maintain HBV suppression 3

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If HIV Infection Occurs During PrEP

Immediately add a boosted protease inhibitor (darunavir/ritonavir or darunavir/cobicistat) and/or dolutegravir to TDF/emtricitabine while awaiting HIV RNA and resistance testing results. 2

• Order resistance testing: Document results to guide subsequent therapy 1, 2
• Switch to recommended initial antiretroviral regimen: Once HIV is confirmed 2
• Establish linkage to HIV care 1

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Common Pitfalls and Caveats

Adherence

• Efficacy is adherence-dependent: Studies show 44-75% risk reduction with good adherence, but low adherence (as in FEM-PrEP trial) results in no protection 5
• Approximately 78-82% of participants in DISCOVER trial reported >95% adherence 6

Weight Gain

• Significant weight gain observed: Median weight gain 1.7 kg with tenofovir alafenamide vs 0.5 kg with tenofovir disoproxil fumarate at 96 weeks 6
• Greater weight gain in women: Medium-term and long-term metabolic consequences require further study 7

Bone Mineral Density

• BMD decreases with TDF: Majority of reduction occurs in first 24-48 weeks and is sustained; 28% of TDF-treated subjects lost ≥5% BMD at spine or ≥7% at hip 8
• Tenofovir alafenamide has more favorable bone effects than tenofovir disoproxil fumarate 9, 6

Pregnancy and Breastfeeding

• Safety data incomplete: No adverse effects found among infants exposed to TDF/FTC during pregnancy, but data are incomplete 1
• Do not prescribe to breastfeeding women 1
• If pregnant: Inform prenatal-care provider of TDF/FTC use and coordinate care 1

Drug Resistance

• Risk of resistance if HIV acquired while on PrEP: Resistance testing is mandatory 1, 2
• For lamivudine-resistant HBV: Can switch to Truvada or add adefovir/tenofovir 1