What is the recommended dose of Tenofovir (Tenofovir Disoproxil Fumarate/TDF or Tenofovir Alafenamide/TAF) for an adult with HIV or hepatitis B?

Tenofovir Dosing for Adults

For HIV treatment in adults with normal renal function, the standard dose is tenofovir disoproxil fumarate (TDF) 300 mg orally once daily, or tenofovir alafenamide (TAF) 25 mg orally once daily as part of combination antiretroviral therapy. 1

HIV Treatment Dosing

Standard Dosing (Normal Renal Function)

• TDF 300 mg once daily taken orally without regard to food 1
• TAF 25 mg once daily as part of fixed-dose combination products 2
• Both formulations require combination with other antiretroviral agents; tenofovir should never be used as monotherapy for HIV 1

Renal Impairment Adjustments (TDF Only)

TDF requires dose-interval adjustments based on creatinine clearance, while TAF does not require adjustment down to CrCl 30 mL/min 1, 3:

• CrCl ≥50 mL/min: 300 mg every 24 hours (no adjustment needed) 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 patients: 300 mg every 7 days (or after approximately 12 hours of dialysis), administered following completion of dialysis 1

TAF is preferred over TDF for patients with CrCl 30-60 mL/min or those with osteopenia/osteoporosis 2, as it maintains efficacy with reduced bone and renal toxicity 4.

HIV Pre-Exposure Prophylaxis (PrEP) Dosing

Daily PrEP Regimens

For most populations at risk, TDF/FTC (300 mg/200 mg) once daily is the recommended regimen 2, 5:

• Initiation: Start with a double dose of TDF/FTC on day 1, followed by single tablet daily thereafter 2
• Continue daily dosing throughout the period of HIV risk 2
• No loading dose is used with TAF/FTC 6

TAF/FTC (25 mg/200 mg) daily is restricted to cisgender men and others whose exposures do NOT include receptive vaginal sex or injection drug use alone 2, 6, 5

On-Demand (2-1-1) PrEP Dosing

On-demand dosing with TDF/FTC is recommended ONLY for cisgender men and others having planned receptive anal sex 2, 5:

• 2 tablets taken 2-24 hours before sexual activity
• 1 tablet 24 hours after the first dose
• 1 tablet 48 hours after the first dose 2
• If additional sexual activity occurs, continue daily single dosing until 2 doses after last activity 2

Critical caveat: For transgender women using gender-affirming hormone therapy, TDF/FTC should be taken with food during 2-1-1 dosing to optimize rectal tissue drug concentrations 2

On-demand dosing is NOT validated for receptive vaginal exposures or TAF/FTC 2, 5

Discontinuation Guidelines

When stopping PrEP, continue dosing based on exposure type 2:

• Rectal exposures: Continue for 2 doses after last sexual activity
• Vaginal/neovaginal exposures: Continue for at least 7 days after last sexual activity

Time to Protection

For receptive vaginal sex, 7 days of daily TDF/FTC dosing is required for full protection 5, whereas receptive anal sex achieves protection within 2-3 days with adequate dosing 5.

Hepatitis B Treatment Dosing

For chronic hepatitis B in adults, the dose is identical to HIV treatment: TDF 300 mg once daily or TAF 25 mg once daily 1, 7:

• TDF 300 mg orally once daily without regard to food 1
• TAF 25 mg orally once daily 7
• Same renal dose adjustments apply as for HIV treatment 1

TAF is preferred for patients with CrCl 30-60 mL/min or bone health concerns 7, as it demonstrates noninferior efficacy to TDF with significantly smaller decreases in bone mineral density and less nephrotoxicity 4.

Critical Monitoring Requirements

Before initiating tenofovir for any indication 1:

• Test for both HBV and HIV infection (tenofovir alone should never be used in HIV-infected patients)
• Assess serum creatinine and estimated creatinine clearance
• Check urine glucose and urine protein
• In patients with chronic kidney disease, also assess serum phosphorus

Warning: Severe acute exacerbations of hepatitis B have been reported after discontinuation of tenofovir in HBV-infected patients; hepatic function must be monitored closely for at least several months after stopping therapy 1.

Common Pitfalls to Avoid

• Never use tenofovir monotherapy for HIV treatment—it must be combined with other antiretrovirals 1
• Do not use TAF/FTC for PrEP in individuals with receptive vaginal exposures—insufficient data support its efficacy 2, 5
• Do not use on-demand PrEP for vaginal exposures or injection drug use—only validated for receptive anal sex in cisgender men 2, 5
• Do not forget renal dose adjustments for TDF—failure to adjust in moderate-to-severe renal impairment leads to excessive drug accumulation and toxicity 1, 3
• Do not initiate PrEP without recent HIV testing—ideally within 7 days using combination antigen/antibody assay 2