What is the recommended dosage and usage of Descovy (emtricitabine and tenofovir alafenamide) for Pre-Exposure Prophylaxis (PrEP)?

Descovy for PrEP: Dosing and Clinical Use

Descovy (emtricitabine 200 mg/tenofovir alafenamide 25 mg) should be taken as one tablet orally once daily and is specifically indicated for men who have sex with men (MSM) and transgender women who have sex with men, particularly those with renal impairment (creatinine clearance 30-60 mL/min), osteopenia, or osteoporosis. 1

Critical Population Limitations

Descovy is NOT recommended for cisgender women or for prevention of HIV-1 infection from receptive vaginal sex. 1 This is a crucial distinction from Truvada (TDF/FTC), which remains the only recommended PrEP option with proven efficacy for females. 2

• Descovy is also NOT recommended for event-driven or "on-demand" (2-1-1) dosing schedules 3, 1
• Daily dosing must be maintained for continued protection 1

Dosing Protocol

• Standard dose: One tablet (emtricitabine 200 mg/tenofovir alafenamide 25 mg) taken orally once daily 1
• Unlike Truvada, there is no recommendation for a double loading dose on the first day when starting Descovy 1
• For MSM, a 1-week lead-in period is recommended before adequate tissue levels are achieved for rectal and penile exposures 3
• Continue for 1 week after the last sexual exposure when discontinuing 3

Pre-Initiation Testing Requirements

Before starting Descovy, obtain the following mandatory tests: 1

• Combined HIV antibody and antigen testing (if acute HIV suspected, add HIV RNA testing) 3
• Serum creatinine and estimated creatinine clearance 3, 1
• Hepatitis B surface antigen (HBsAg) 3, 1
• Hepatitis C antibody 3, 1
• Three-site STI screening (rectal, pharyngeal, urogenital) for gonorrhea and chlamydia by NAAT 3
• Syphilis testing 1

Do not initiate Descovy in persons with suspected or confirmed HIV infection. 1

Ongoing Monitoring Schedule

Every 3 months: 3, 1

• HIV testing with combination antigen-antibody assay
• Three-site STI screening for gonorrhea and chlamydia by NAAT
• Syphilis testing

First quarterly visit, then annually: 1

• Creatinine clearance monitoring

More frequent renal monitoring (every 3-6 months) is required for: 3

• Patients >50 years old
• Those taking hypertension or diabetes medications
• Baseline eGFR <90 mL/min

Efficacy Evidence

The DISCOVER trial demonstrated that emtricitabine/tenofovir alafenamide was non-inferior to emtricitabine/tenofovir disoproxil fumarate for HIV prevention in MSM and transgender women who have sex with men (IRR 0.47,95% CI 0.19-1.15). 4 After 8,756 person-years of follow-up, HIV incidence was 0.16 infections per 100 person-years in the Descovy group versus 0.34 in the Truvada group. 4

Descovy demonstrated superior bone mineral density and renal biomarker safety profiles compared to Truvada in all six prespecified endpoints. 4 This makes it the preferred option specifically for MSM with renal impairment or bone health concerns. 1

Important Clinical Caveats

• PrEP prescriptions should not exceed 90 days without interval HIV testing 2
• PrEP does not prevent other sexually transmitted infections—only HIV 2
• Use caution when discontinuing in patients with chronic hepatitis B due to risk of acute flares or hepatic decompensation 3
• If HIV infection occurs during PrEP, immediately add a boosted protease inhibitor (darunavir/ritonavir or darunavir/cobicistat) and/or dolutegravir while awaiting resistance testing 3

When to Choose Descovy Over Truvada

Descovy is preferred over Truvada specifically for MSM with: 1

• Renal impairment (creatinine clearance 30-60 mL/min)
• Osteopenia or osteoporosis
• Concerns about long-term bone or kidney health

For all other populations, including cisgender women, Truvada (TDF/FTC) remains the recommended first-line PrEP regimen. 2, 3