Can I take losartan (angiotensin II receptor antagonist) while taking Biktarvy (bictegravir/emtricitabine/tenofovir alafenamide)?

Concurrent Use of Losartan and Biktarvy: Drug Interaction Assessment

Losartan can be safely taken concurrently with Biktarvy (bictegravir/emtricitabine/tenofovir alafenamide) as there are no significant drug interactions between these medications that would affect efficacy or safety.

Drug Interaction Analysis

Biktarvy Components and Metabolism

• Biktarvy is a single-tablet regimen containing bictegravir (an integrase strand transfer inhibitor), emtricitabine, and tenofovir alafenamide for HIV-1 treatment 1
• Bictegravir is metabolized primarily by CYP3A4 enzymes
• Unlike protease inhibitors, Biktarvy does not require pharmacologic boosting (no ritonavir or cobicistat) 1

Losartan Metabolism

• Losartan is metabolized primarily by CYP3A4, 2C9, and 2C10 isoenzymes 2
• It is converted to its active metabolite E-3174, which is 10-40 times more potent than losartan itself 2
• Losartan has a favorable drug-drug interaction profile with minimal clinically relevant interactions with inhibitors and stimulators of the CYP450 system 2

Key Considerations

1. No documented interactions: Unlike protease inhibitors which have significant interactions with many medications, Biktarvy does not have documented interactions with losartan

2. Antiretroviral guidelines: The International Antiviral Society-USA panel guidelines do not list angiotensin receptor blockers (ARBs) like losartan as medications with significant interactions with integrase inhibitor-based regimens like Biktarvy 3

3. Hypertension management: Losartan is actually a preferred antihypertensive agent in certain clinical scenarios:

   • The 2020 ACR gout management guidelines conditionally recommend choosing losartan preferentially as an antihypertensive when feasible 3
   • Losartan has been shown to be effective in reducing blood pressure with minimal adverse effects 4

Clinical Recommendations

Monitoring Parameters

• Renal function should be monitored when initiating therapy with both medications:
  • Biktarvy can be used in patients with creatinine clearance ≥30 mL/min 1
  • Losartan generally does not require dosage adjustment in patients with mild to moderate renal dysfunction 2

Specific Patient Populations

• For patients with HIV and hypertension, losartan may be particularly beneficial:
  • Losartan has shown benefits in regression of left ventricular hypertrophy 3, 4
  • It has a favorable side effect profile compared to some other antihypertensives 4

Potential Advantages of Losartan

• Losartan has been shown to be well-tolerated in various patient populations 2, 4
• It can be administered once daily, which may improve adherence 2
• The maximum recommended daily dose is 100mg, which can be given as a once-daily dose or split into two doses 2

Conclusion

Based on the available evidence, there is no contraindication to using losartan concurrently with Biktarvy. Regular monitoring of blood pressure and renal function is recommended as part of standard care for patients on these medications, but no special precautions or dosage adjustments are required specifically due to this combination.