Truvada (Tenofovir Disoproxil Fumarate/Emtricitabine) Dosage Adjustment in Renal Impairment
Truvada dosage should be adjusted to every 48 hours for your patient with GFR 56 mL/min, as this falls within the 30-49 mL/min range requiring dose adjustment. 1, 2
Assessment of Renal Function
- Your patient has moderate renal impairment with a creatinine of 1.55 mg/dL and GFR of 56 mL/min 1
- Tenofovir is principally eliminated by the kidney, making dose adjustment necessary in patients with reduced renal function 1
- The patient's history of gout and allopurinol use are relevant as they indicate underlying metabolic issues that may affect renal function 2
Specific Dosing Recommendations for Truvada in Renal Impairment
- For patients with creatinine clearance 50-80 mL/min: No adjustment needed for standard once-daily dosing 2
- For patients with creatinine clearance 30-49 mL/min: Administer Truvada every 48 hours instead of daily 2
- For patients with creatinine clearance <30 mL/min: Truvada combination tablet should not be used 2
Component-Specific Considerations
Tenofovir Disoproxil Fumarate (TDF)
- For creatinine clearance 30-49 mL/min: 300 mg every 48 hours 1
- TDF has been associated with nephrotoxicity, particularly in patients with pre-existing renal dysfunction 2
Emtricitabine
- For creatinine clearance 30-49 mL/min: 200 mg every 48 hours 2
- Emtricitabine requires dose adjustment in renal impairment as it is primarily eliminated through the kidneys 2
Monitoring Recommendations
- Regular monitoring of renal function is essential when using TDF in patients with impaired renal function 2, 1
- Monitor serum creatinine, estimated creatinine clearance, urine glucose, and urine protein on a clinically appropriate schedule 1
- Watch for signs of proximal tubular dysfunction such as euglycemic glycosuria, increased urinary phosphorus excretion, hypophosphatemia, or worsening proteinuria 2
- Consider discontinuing TDF if renal function declines by >25% from baseline or falls below 60 mL/min/1.73 m² 2
Alternative PrEP Options to Consider
- Tenofovir alafenamide/emtricitabine (Descovy) has shown improved renal safety profile compared to TDF/FTC and may be a better option for patients with renal concerns 3
- However, Descovy is not currently FDA-approved for PrEP in individuals at risk of HIV-1 infection from receptive vaginal sex 3
- If renal function continues to decline, consider alternative HIV prevention strategies 2
Important Clinical Considerations
- PrEP with TDF/FTC has been associated with subclinical tubular dysfunction after 6 months of use, even in patients with normal baseline renal function 4
- Concurrent use of nephrotoxic medications should be avoided when possible 2
- The patient's allopurinol therapy for gout should be continued as it may help protect renal function 2
By adjusting the Truvada dosing schedule to every 48 hours and implementing appropriate monitoring, you can provide effective HIV pre-exposure prophylaxis while minimizing the risk of further renal impairment in your patient.