Tenofovir Dosing for Hepatitis B
For adults with chronic hepatitis B, the standard dose is tenofovir disoproxil fumarate (TDF) 300 mg once daily or tenofovir alafenamide (TAF) 25 mg once daily, with TAF strongly preferred in patients with renal impairment, osteoporosis, or risk factors for nephrotoxicity. 1
Standard Dosing Regimens
Adults
Pediatric Patients
- TDF: Approved for children ≥12 years of age (300 mg daily) 1
- TAF: Approved for children ≥12 years of age (25 mg daily) 1
Dose Adjustments for Renal Impairment
TDF requires dose adjustment based on creatinine clearance (CrCl), while TAF does not require adjustment except in severe cases. 2, 1
TDF Dose Adjustments (Cockcroft-Gault):
- CrCl ≥50 mL/min: 300 mg once daily (no adjustment needed) 3
- CrCl 30-49 mL/min: 300 mg every 48 hours 3, 4
- CrCl 10-29 mL/min: 300 mg every 72-96 hours 3, 4
- Hemodialysis patients: 300 mg once weekly (every 7 days) following dialysis session 3
Research evidence supports these adjustments maintain viral suppression while improving renal function. A randomized trial demonstrated that both every-48-hour and every-72-hour dosing maintained virological control without breakthrough, with the every-72-hour regimen showing superior renal recovery 4. Real-world data confirm that reduced-dose TDF maintains viral suppression in 99% of patients with renal impairment 5.
TAF in Renal Impairment:
- CrCl ≥15 mL/min: 25 mg once daily (no adjustment) 2, 6
- CrCl <15 mL/min not on hemodialysis: Not approved 2
- Hemodialysis patients: Can be used at 25 mg daily 7
TAF is strongly preferred over TDF in patients with eGFR <60 mL/min/1.73m² because it causes significantly less decline in renal function and bone mineral density. 2 Phase 3 studies demonstrate TAF maintains stable renal function over 96 weeks in patients with moderate-to-severe renal impairment and even those on hemodialysis 7.
Choosing Between TDF and TAF
The 2025 EASL guidelines recommend TAF as preferred first-line therapy over TDF in patients with: 2
- Renal insufficiency (eGFR <60 mL/min/1.73m²)
- Osteoporosis or osteopenia
- Hypophosphatemia
- Decompensated cirrhosis
- Poorly controlled hypertension
- Diabetes mellitus
- Age >60 years
- Concurrent nephrotoxic medications
- Organ transplantation
This preference is based on 96-week data showing TAF causes significantly less decline in eGFR and bone mineral density compared to TDF, with equivalent antiviral efficacy 2. Switching from TDF to TAF has been shown to improve bone mineral density and reduce fracture risk 2.
If TAF is unavailable or not reimbursed, entecavir is the recommended alternative, as it does not cause renal or bone toxicity. 2
Monitoring Requirements
For TDF Treatment:
- Baseline: Serum creatinine, creatinine clearance, serum phosphate, urine glucose, urine protein 1
- During treatment: Monitor creatinine clearance, serum phosphate, urine glucose, and urine protein at least annually 1
- High-risk patients: More frequent monitoring (every 3-6 months) 2
For TAF Treatment:
- Baseline: Serum creatinine, serum phosphorus, creatinine clearance, urine glucose, urine protein 1
- During treatment: Monitor as clinically appropriate 1
Critical Safety Considerations
Always test for HIV before initiating tenofovir for hepatitis B. 1 Using tenofovir as monotherapy in undiagnosed HIV coinfection can lead to HIV resistance.
Monitor for posttreatment hepatitis flares if tenofovir is discontinued. Severe acute exacerbations of hepatitis B can occur after stopping treatment, requiring close monitoring of hepatic function for several months 1.
The evidence strongly supports that both TDF and TAF are highly effective for hepatitis B, with 90-93% achieving viral suppression at 48 weeks 1. However, the superior renal and bone safety profile of TAF makes it the preferred option when available, particularly in older patients and those with comorbidities 2.