TDF Dosing and Administration
The standard dose of tenofovir disoproxil fumarate (TDF) is 300 mg once daily for adults and pediatric patients weighing ≥35 kg, with mandatory dose-interval adjustments required for patients with creatinine clearance <50 mL/min. 1
Standard Dosing
Adults and Pediatric Patients ≥35 kg
- 300 mg once daily (for both HIV-1 and chronic hepatitis B)
- Can be taken without regard to food 1
Pediatric Patients (2 years and older, 17-35 kg)
Weight-based dosing using 8 mg/kg once daily (maximum 300 mg):
- 17 to <22 kg: 150 mg once daily
- 22 to <28 kg: 200 mg once daily
- 28 to <35 kg: 250 mg once daily 1
Weight should be monitored periodically with dose adjustments as needed.
Renal Impairment Dosing Adjustments
Critical consideration: TDF is principally eliminated by the kidney, and significant drug accumulation occurs with moderate-to-severe renal impairment. 1
Dosing by Creatinine Clearance (CrCl):
| CrCl (mL/min) | Dosing Interval |
|---|---|
| ≥50 | 300 mg every 24 hours (no adjustment needed) |
| 30-49 | 300 mg every 48 hours |
| 10-29 | 300 mg every 72-96 hours |
| Hemodialysis | 300 mg every 7 days (after dialysis session) [1] |
Important: Calculate CrCl using ideal (lean) body weight. 1
Alternative Dosing for Moderate Renal Impairment
Recent evidence suggests 150 mg once daily may be preferable to 300 mg every 48 hours for moderate renal impairment (CrCl 30-49 mL/min), as it provides comparable systemic exposure while maintaining more consistent daily drug levels and reducing exposure variability. 2 This daily dosing approach is more convenient and may reduce the risk of both supratherapeutic peaks and subtherapeutic troughs seen with extended dosing intervals. 3
PrEP-Specific Dosing (HIV Prevention)
Daily Oral PrEP
- Initiation: Double dose of TDF/FTC on day 1, then single tablet daily thereafter 4
- Discontinuation timing:
- Rectal exposures: Continue until 2 doses after last sexual activity
- Vaginal/neovaginal exposures: Continue until at least 7 days after last sexual activity 4
On-Demand (2-1-1) Dosing
Recommended for cisgender men and others having planned receptive anal sex only (not for vaginal exposures):
- 2 tablets 2-24 hours before sex
- 1 tablet 24 hours after first dose
- 1 tablet 48 hours after first dose
- If ongoing sexual activity: continue daily dosing until 2 doses after last activity 4
Critical caveat: Transgender women using gender-affirming hormones should take 2-1-1 dosing with food due to potentially lower rectal tissue drug concentrations. 4
Monitoring Requirements
Before initiating TDF 1:
- Test for HBV and HIV-1 infection
- Assess serum creatinine and estimated CrCl
- Assess urine glucose and urine protein
- In patients with chronic kidney disease: also assess serum phosphorus
During treatment: Monitor renal function on a clinically appropriate schedule, as TDF can cause acute renal failure and Fanconi syndrome. 1
Special Populations
Hepatic Impairment
No dose adjustment required for any degree of hepatic impairment, including Child-Pugh C disease. 5, 1 TDF is not metabolized by hepatic cytochrome enzymes.
Pregnancy and Breastfeeding
TDF/FTC daily oral PrEP is the recommended regimen for pregnant or breastfeeding individuals. 4
Patients with Osteopenia/Osteoporosis
Consider switching to TAF/FTC rather than TDF/FTC, as TAF causes less bone mineral density loss. 4 However, bone density scans are not necessary before initiating TDF-based PrEP. 4
Common Pitfalls
- Failing to adjust for renal impairment: Always calculate CrCl before prescribing and adjust dosing intervals accordingly
- Using extended intervals without considering alternatives: For moderate renal impairment, 150 mg daily may be superior to 300 mg every 48 hours
- Inadequate monitoring after discontinuation in HBV patients: Severe hepatitis exacerbations can occur; monitor closely for several months 1
- Prescribing on-demand PrEP for vaginal exposures: 2-1-1 dosing is only validated for receptive anal sex 4