Managing Anemia in Patients Taking PrEP with TDF/FTC
Anemia is not a recognized adverse effect of emtricitabine/tenofovir disoproxil fumarate (TDF/FTC) for HIV pre-exposure prophylaxis, and routine hemoglobin monitoring is not recommended in PrEP guidelines. 1, 2
Key Clinical Distinction
The evidence provided regarding anemia relates to ribavirin for Lassa fever prophylaxis 3 and hepatitis C treatment with protease inhibitors 3, which are entirely different clinical contexts. These medications cause hemolytic anemia through distinct mechanisms unrelated to TDF/FTC PrEP.
- TDF/FTC does not cause anemia as a recognized adverse effect in HIV prevention trials or clinical practice 4, 5
- The DISCOVER trial (5,387 participants, 96 weeks) showed no significant anemia signals with either TDF/FTC or TAF/FTC formulations 4, 5
- FDA labeling for emtricitabine lists anemia only in pediatric HIV treatment populations (7% incidence), not in PrEP use 6
Standard PrEP Monitoring Does Not Include Hemoglobin
The established monitoring protocol for TDF/FTC PrEP focuses on renal function, HIV testing, and STI screening—not hematologic parameters. 1, 2
Required Baseline Testing Before PrEP Initiation:
- HIV antibody/antigen testing (4th generation) 1, 2
- Serum creatinine with calculated creatinine clearance (contraindicated if CrCl <60 mL/min) 1, 2
- Hepatitis B surface antigen (HBsAg) 1, 2
- Hepatitis C antibody 1, 2
- STI screening (gonorrhea, chlamydia, syphilis) 1, 2
- Pregnancy testing for individuals of childbearing potential 1, 2
Ongoing Monitoring Schedule:
- Every 3 months: HIV testing, STI screening, adherence assessment, pregnancy testing 1, 2
- Every 6 months: Creatinine clearance (or every 3 months if age >50, baseline CrCl <90 mL/min, diabetes, or hypertension) 1, 2
- Annually: Hepatitis C antibody testing 1, 2
Clinical Approach for Patients with Pre-Existing Anemia
If a patient has a history of anemia, this does not contraindicate TDF/FTC PrEP, as the medication does not worsen anemia. 6, 4
Management Algorithm:
Evaluate and treat the underlying cause of anemia before or concurrent with PrEP initiation using standard hematologic workup (iron studies, B12/folate, reticulocyte count, etc.)
Proceed with standard PrEP initiation once HIV testing is negative and CrCl ≥60 mL/min 1, 2
Do not add hemoglobin monitoring to the PrEP protocol unless the patient's underlying anemia condition independently requires it for other medical reasons
Counsel the patient that TDF/FTC does not cause or worsen anemia, distinguishing it from other medications they may have heard about (such as ribavirin or hepatitis C treatments)
Patients with Impaired Renal Function
Renal function is the critical safety parameter for TDF-based PrEP, not anemia. 1, 2
Renal Function Thresholds:
- TDF/FTC is contraindicated if creatinine clearance <60 mL/min 1, 2
- Consider TAF/FTC alternative for men who have sex with men with CrCl 30-60 mL/min who have osteopenia, osteoporosis, or high fracture risk 7
- TAF/FTC lacks efficacy data for cisgender women with vaginal exposures and should not be used in this population 7
Enhanced Renal Monitoring:
- Monitor creatinine clearance every 3 months (rather than every 6 months) for patients with: 1, 2
- Age >50 years
- Baseline CrCl <90 mL/min
- Diabetes
- Hypertension
- Concomitant nephrotoxic medications
Common Pitfalls to Avoid
Do not conflate anemia risks from hepatitis C treatment regimens (ribavirin, protease inhibitors) with HIV PrEP medications—these are pharmacologically distinct 3
Do not add unnecessary hemoglobin monitoring to PrEP protocols based on misunderstanding of adverse effect profiles 1, 2
Do not withhold PrEP from patients with pre-existing anemia unless they have contraindications related to renal function or HIV status 1, 2
Do not use TAF/FTC in cisgender women seeking PrEP for vaginal exposures, even if they have renal concerns—efficacy data only exist for TDF/FTC in this population 7