Tenofovir Dosing Recommendations
Standard Adult Dosing
For HIV treatment in adults with normal renal function, tenofovir disoproxil fumarate (TDF) 300 mg once daily or tenofovir alafenamide (TAF) 25 mg once daily (as part of fixed-dose combinations) are the recommended doses. 1, 2
For chronic hepatitis B in adults with normal renal function:
HIV Pre-Exposure Prophylaxis (PrEP) Dosing
Daily PrEP Regimens
TDF/FTC (300 mg/200 mg) once daily is recommended for all populations at risk, with a double dose on day 1 followed by single tablet daily thereafter. 1, 2
- For receptive vaginal sex, 7 days of daily dosing is required for full protection 2
- For receptive anal sex, protection is achieved within 2-3 days with adequate dosing 2
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. 1, 2
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: 1, 2
- 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
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. 1, 2
PrEP Discontinuation
When stopping PrEP, continue dosing based on exposure type: 1, 2
- Rectal exposures: 2 doses after last sexual activity
- Vaginal/neovaginal exposures: at least 7 days of dosing after last sexual activity
Renal Impairment Dosing Adjustments
TDF Dose Modifications by Creatinine Clearance
For creatinine clearance ≥50 mL/min: TDF 300 mg every 24 hours 1
For creatinine clearance 30-49 mL/min: TDF 300 mg every 48 hours 1, 3
For creatinine clearance 10-29 mL/min: TDF 300 mg every 72-96 hours 1, 3
For creatinine clearance <10 mL/min without hemodialysis: TDF is not recommended 1
For hemodialysis patients: TDF 300 mg every 7 days or after approximately 12 hours of dialysis (typically once weekly after dialysis session) 1, 3
Alternative Dosing Strategy for Moderate Renal Impairment
TDF 150 mg once daily provides comparable systemic exposure to 300 mg every 48 hours in patients with moderate renal impairment (CrCl 30-49 mL/min) and offers more convenient daily dosing. 4, 5
TAF Dose Modifications
For creatinine clearance ≥15 mL/min: TAF 25 mg every 24 hours 1
For creatinine clearance <15 mL/min without dialysis: TAF is not recommended 1
Selecting Agents in Renal Dysfunction
Entecavir, TAF, and besifovir are preferred over TDF in treatment-naïve chronic hepatitis B patients with or at risk of renal dysfunction or metabolic bone disease. 1
TDF-based PrEP is contraindicated in patients whose creatinine clearance is <60 mL/min/1.73 m². 6
Patients with baseline creatinine clearance of 60-90 mL/min/1.73 m² require intensified renal monitoring every 1-3 months. 6
Pediatric Dosing
Chronic Hepatitis B in Children
For adolescents aged 12-18 years: TDF 8 mg/kg daily (up to 300 mg) 1
TDF is approved for use in persons older than 12 years. 1
For children aged 2-17 years with lamivudine resistance, combination therapy or entecavir may be considered based on adult guidelines. 1
HIV Treatment in Children
Tenofovir 300 mg orally once daily as part of HAART regimen for older children who can receive adult dosing 1
Tenofovir is not approved for use in HIV-infected children aged <18 years, and no pediatric formulation exists; it can be used for older HIV-infected children who can receive adult dosage. 1
Pregnancy and Breastfeeding
TDF/FTC daily oral PrEP is the recommended oral regimen for people who are pregnant or breast/chest feeding. 1
Long-acting cabotegravir has a growing safety profile in pregnancy and breast/chest feeding and can be used safely in these settings. 1
Hepatic Impairment
No tenofovir disoproxil fumarate dose adjustment is warranted in the setting of hepatic impairment. 7, 3
Subjects with and without hepatic impairment displayed similar tenofovir systemic exposures without evidence of substantial alterations in drug disposition. 3
Critical Monitoring Requirements
Renal Function Monitoring for PrEP
Measure serum creatinine and calculate eGFR before starting daily oral TDF/FTC PrEP. 6
Schedule the first follow-up visit within 30 days of PrEP initiation and repeat serum creatinine measurement. 6
Perform serum creatinine and creatinine-clearance testing at baseline, at 1 month, then every 3 months during the first year, and every 6 months thereafter if renal function remains stable. 6
For TAF-based PrEP (Descovy), measure creatinine clearance at the first quarterly visit (approximately 3 months after initiation) and then annually thereafter. 6
High-Risk Patients Requiring More Frequent Monitoring (Every 1-3 Months)
Patients with baseline creatinine clearance of 60-90 mL/min/1.73 m² require intensified monitoring. 6
Individuals taking antihypertensive or diabetes medications should be monitored every 1-3 months. 6
Patients with decompensated cirrhosis, poorly controlled hypertension, proteinuria, uncontrolled diabetes, active glomerulonephritis, concurrent nephrotoxic drugs, or solid-organ transplantation need monitoring at 1-3-month intervals. 6
If creatinine clearance falls below 60 mL/min/1.73 m², initiate more frequent renal monitoring. 6
If serum phosphate drops below 2 mg/dL, increase monitoring frequency. 6
Drug Interactions and Special Considerations
With the exception of didanosine and atazanavir, which require dosage modifications, no clinically significant drug interactions have been observed with tenofovir DF. 7
Tenofovir is not a substrate, inducer or inhibitor of human cytochrome P450 enzymes in vitro or in vivo. 7
The oral bioavailability of tenofovir is enhanced by administration with a high-fat meal, but is similar at steady state when administered with or without a typical meal. 7
Common Pitfalls and Caveats
The approved extended dosing intervals of 72-96 hours for severe renal impairment exhibit high drug exposure variability, initially resulting in supratherapeutic levels followed by suboptimal levels preceding the subsequent dose. 5
Patients with chronic HBV switching HIV regimens must continue tenofovir (TAF or TDF) to maintain HBV suppression, with a risk of severe hepatitis flare or hepatic decompensation if tenofovir is discontinued. 6
TAF/FTC should not be used for PrEP in individuals with receptive vaginal exposures due to insufficient data supporting its efficacy. 1, 2
On-demand PrEP is only validated for receptive anal sex in cisgender men and should not be used for vaginal exposures or injection drug use. 1, 2
Do not initiate PrEP without recent HIV testing, ideally within 7 days using combination antigen/antibody assay. 2