Sertraline and Lonafarnib: Interaction Details
AI-assisted, pharmacist-reviewed · AI content regenerated Jul 11, 2026 · Source data updated Jul 2, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Lonafarnib
Sertraline
No brand names on record
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.
Both of your medicines can affect the timing of your heartbeat. Lonafarnib (Zokinvy) and sertraline can each stretch out a part of the heart's electrical cycle called the QT interval. When two drugs that do this are taken together, the effect can add up and, in rare cases, lead to a dangerous irregular heartbeat.
This concern is based mostly on how the drugs work rather than lots of real-world reports, so try not to panic. Please don't stop or change either medicine on your own. Talk with your doctor or pharmacist. They can decide if both are truly needed and may check your heart with an ECG to keep you safe.
Effect: Additive QTc prolongation with increased risk of torsade de pointes, other serious arrhythmias, and sudden death.
Mechanism: Both agents independently prolong the QT interval; combined use produces additive delayed cardiac repolarization (pharmacodynamic interaction, not CYP-mediated). Neither is a prodrug relevant here.
- Direction: Increased QT-prolonging effect.
- Severity/Evidence: Major, but theoretical.
- Onset: Unspecified.
- Management: Avoid concomitant use if possible. If unavoidable, obtain baseline and periodic ECGs at initiation and during co-therapy; monitor and correct electrolytes (K+, Mg2+), and review other QT-prolonging drugs.
What happens
An increased risk of QT interval prolongation and torsade de pointes
Interaction Deep Dive
Do not administer lonafarnib, an agent known to prolong the QTc interval, together with other medications that also prolong QTc, because doing so can produce a larger prolongation of the QTc interval along with adverse events tied to QTc prolongation, such as torsade de pointes, additional serious arrhythmias, and sudden death. When the combination is unavoidable, obtain ECGs at the start of and throughout the period of concurrent use1.
Why it happens (mechanism)
Additive QT interval prolongation
How to manage this interaction
Here is how a care team usually handles this:
- Avoid together when possible. Your prescriber may look at whether both drugs are truly needed or if an alternative exists.
- Closer monitoring. If you do need both, your team may order an ECG when starting and during treatment to watch your heart rhythm, and may check blood levels like potassium and magnesium.
What you should do: Keep taking both exactly as prescribed unless your doctor tells you otherwise. Tell your pharmacist about every medicine and supplement you take. Report fainting, dizziness, or a fluttering or pounding heartbeat right away.
Management is individual — confirm any change with your pharmacist or prescriber.
Common questions
Can I take Sertraline and Lonafarnib together?
Lonafarnib and sertraline can each prolong the QT interval, so combining them may raise the risk of a dangerous heart rhythm; your care team may avoid the combination or monitor your heart with ECGs if both are needed. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Sertraline and Lonafarnib 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 is the Sertraline and Lonafarnib interaction managed?
Here is how a care team usually handles this: Avoid together when possible. Your prescriber may look at whether both drugs are truly needed or if an alternative exists. Closer monitoring. If you do need both, your team may order an ECG when starting and during treatment to watch your heart rhythm, and may check blood levels like potassium and magnesium. What you should do: Keep taking both exactly… Management is individual — always follow your own care team's guidance.
How strong is the evidence for this interaction?
The evidence is graded "theoretical". Predicted from the drugs' pharmacology; not yet confirmed in people.
From our Q&A
Real reader questions about these medications, each personally answered by our pharmacist:
Questions for your pharmacist
- Does my dose of Sertraline or Lonafarnib 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 (1)
- Product Information: ZOKINVY(TM) oral capsules, lonafarnib oral capsules. Eiger BioPharmaceuticals Inc (per FDA), Palo Alto, CA, 2024. DailyMed
Keep reading about Lonafarnib
Keep reading about Sertraline
These medications also interact with supplements
Prescription drugs aren't the whole picture — herbal and dietary supplements can interact with them too. From the evidence-graded Natural Medicines database:
major · moderate · minor — check everything you take with our drug–supplement interaction checker.
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