What are the considerations for using Biktarvy (bictegravir, emtricitabine, tenofovir alafenamide) in patients with a history of methamphetamine use and potential Impaired renal function?

Biktarvy and Methamphetamine Use: Key Considerations

Biktarvy (bictegravir/emtricitabine/tenofovir alafenamide) can be safely used in patients with methamphetamine use history, but renal function monitoring is critical—check baseline creatinine clearance and do not initiate if CrCl is below 30 mL/min, with more frequent monitoring (every 3-6 months) required for patients with baseline eGFR <90 mL/min or other renal risk factors. 1

Pre-Initiation Renal Assessment

Before prescribing Biktarvy to any patient, including those with substance use history:

• Measure serum creatinine, estimated creatinine clearance, urine glucose, and urine protein as clinically appropriate 1
• In patients with chronic kidney disease, also assess serum phosphorus 1
• Do not initiate Biktarvy if estimated creatinine clearance is below 30 mL/min (except in virologically-suppressed adults on chronic hemodialysis with CrCl <15 mL/min) 1
• Biktarvy is not recommended in patients with severe renal impairment (CrCl 15 to <30 mL/min) or ESRD not on hemodialysis 1

Methamphetamine-Specific Renal Concerns

Methamphetamine use poses additional nephrotoxicity risk that compounds with tenofovir alafenamide (TAF):

• Methamphetamine users may have subclinical renal impairment from vasoconstriction, rhabdomyolysis, or hypertension, making baseline renal assessment even more critical 1
• TAF has lower renal toxicity than tenofovir disoproxil fumarate (TDF), with plasma tenofovir exposures 90% lower than TDF-based regimens, reducing nephrotoxicity risk 2
• In patients with severe renal impairment (CrCl 15-29 mL/min), TAF exposures increase by 92% and tenofovir exposures by 5.7-fold, though these remain lower than TDF exposures in patients with normal renal function 2

Ongoing Monitoring Requirements

For patients with methamphetamine use history on Biktarvy:

• Monitor serum creatinine and eGFR every 3-6 months if the patient is over 50 years old, taking hypertension/diabetes medications, or has baseline eGFR <90 mL/min 3
• Standard monitoring is every 6-12 months for patients without additional risk factors 3
• Continue monitoring urine glucose and urine protein during treatment, and serum phosphorus in those with chronic kidney disease 1

Hepatitis B Co-Infection Caveat

• Test for hepatitis B surface antigen before initiating Biktarvy 1
• If HBsAg-positive, do not discontinue Biktarvy without alternative HBV-active therapy, as severe acute exacerbations of hepatitis B can occur, particularly in patients with cirrhosis 3, 4
• Biktarvy contains emtricitabine and TAF, both active against HBV, making it suitable for HIV/HBV co-infection 5

Dosing in Renal Impairment

• For CrCl ≥30 mL/min: Standard dose of one 50/200/25 mg tablet once daily with or without food 1
• For virologically-suppressed adults on chronic hemodialysis with CrCl <15 mL/min: Administer after hemodialysis completion 1
• For CrCl 15 to <30 mL/min or ESRD not on hemodialysis: Biktarvy is not recommended 1

Clinical Evidence in Renal Impairment

Real-world data supports Biktarvy use in advanced renal disease:

• Six case reports of Biktarvy in ESRD patients on hemodialysis showed successful virologic suppression with once-daily dosing, elimination of drug interactions, and improved quality of life 6
• TAF-based regimens in patients with CrCl 30-69 mL/min showed stable creatinine clearance and significant improvements in proteinuria, albuminuria, and bone mineral density through 96 weeks 7
• Bictegravir has a high genetic barrier to resistance, with no treatment-emergent resistance in phase 3 trials through 96 weeks 5

Practical Algorithm for Methamphetamine Users

1. Obtain baseline CrCl, urinalysis, and HBsAg 1
2. If CrCl ≥30 mL/min: Initiate standard Biktarvy dosing 1
3. If CrCl 15-29 mL/min: Choose alternative regimen (Biktarvy not recommended) 1
4. If CrCl <15 mL/min on hemodialysis and virologically suppressed: Biktarvy can be used post-dialysis 1
5. Monitor renal function every 3-6 months if baseline eGFR <90 mL/min or active substance use 3
6. Screen for HIV every 3 months if using as PrEP, or monitor viral load if treating established HIV 3

budget:token_budget Tokens used this turn: 4733 Total tokens used: 4733 Tokens remaining: 195267