Thioridazine and Lenacapavir Injection: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Thioridazine
No brand names on recordLenacapavir Injection
How we grade severity & evidence
Severity levels
- Contraindicated: These should generally not be used together.
- Major: Potentially serious — often needs a change or close monitoring.
- Moderate: Can be significant — usually manageable with monitoring.
- Minor: Usually limited clinical impact.
Evidence grades
- Established: Well documented — supported by controlled studies or strong clinical data.
- Probable: Good supporting evidence, though not definitively proven.
- Suspected: Some evidence suggests this interaction, but it is not well established.
- Possible: Limited or conflicting evidence; the interaction may occur.
- Theoretical: Predicted from the drugs' pharmacology; not yet confirmed in people.
Ratings come from the documented interaction literature and are reviewed by a pharmacist. They describe the documented risk of the combination, not what will necessarily happen to you — your dose, timing, and health picture all matter.
What happens
Reduced lenacapavir exposure which may result in the loss of therapeutic effect and development of resistance to lenacapavir
Interaction Deep Dive
Concomitant use of lenacapavir (SUNLENCA®) with a moderate CYP3A inducer is not recommended, as coadministration reduces lenacapavir exposure which may result in the loss of therapeutic effect and development of resistance to lenacapavir2; however, lenacapavir (YEZTUGO®) and a moderate CYP3A inducer can be used concomitantly with dosage adjustments. For individuals receiving YEZTUGO® and initiating therapy with a moderate CYP3A inducer, continue to maintain scheduled injection dosing (YEZTUGO® 927 mg SUBQ once every 6 months) plus administer the following supplemental YEZTUGO® doses: administer 463.5 mg SUBQ on the day of moderate CYP3A inducer initiation. Dosing recommendations are not available for the initiation of YEZTUGO® in individuals already receiving moderate CYP3A inducers, nor in individuals receiving the weekly oral dosage. If a moderate CYP3A inducer is coadministered for longer than 6 months, continue to administer supplemental doses of YEZTUGO® every 6 months (26 weeks +/- 2 weeks) from CYP3A inducer initiation. After stopping a moderate CYP3A inducer, continue the once every 6 months scheduled injection dosing of YEZTUGO® 1.
Why it happens (mechanism)
Induction of CYP3A4-mediated metabolism of lenacapavir
Literature reports
1 report — tap to read
a) In the drug interaction studies conducted in subjects without HIV-1, concomitant administration of single dose of lenacapavir 300 mg orally with efavirenz (fasted) [inducer of CYP3A (moderate) and P-gp and UGT] 600 mg once daily, the mean ratio for AUC and Cmax of lenacapavir with and without efavirenz were 0.44 (90% CI, 0.32 to 0.59) and 0.64 (90% CI, 0.45 to 0.92) respectively 21.
Common questions
Can I take Thioridazine and Lenacapavir Injection together?
Reduced lenacapavir exposure which may result in the loss of therapeutic effect and development of resistance to lenacapavir Always confirm with your pharmacist or prescriber before making any change.
How serious is the Thioridazine and Lenacapavir Injection interaction?
It is rated major. Potentially serious — often needs a change or close monitoring.
How quickly could this interaction happen?
The documented onset is "unspecified". The timing of this interaction is not well characterized.
How strong is the evidence for this interaction?
The evidence is graded "probable". Good supporting evidence, though not definitively proven.
Questions for your pharmacist
- Does my dose of Thioridazine or Lenacapavir Injection need adjusting while I take them together?
- What symptoms should prompt me to call you or my prescriber right away?
- Does the timing of my doses matter for this combination?
- Is there a safer alternative to one of these medications for me?
References (2)
- Product Information: YEZTUGO(R) oral tablets, subcutaneous injection, lenacapavir oral tablets, subcutaneous injection. Gilead Sciences Inc (per manufacturer), Foster City, CA, 2025. DailyMed
- Product Information: SUNLENCA(R) oral tablets, subcutaneous injection, lenacapavir oral tablets, subcutaneous injection. Gilead Sciences Inc (per FDA), Foster City, CA, 2024. DailyMed
Keep reading about Thioridazine
Keep reading about Lenacapavir Injection
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