Sertraline and Posaconazole: 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
Posaconazole
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.
Posaconazole (Noxafil) is an antifungal that can slow down how your body breaks down certain medicines, and it can also affect your heart's rhythm on its own. Sertraline is an antidepressant that can also slightly affect heart rhythm. When taken together, sertraline levels may rise, and the two drugs together can add up to a greater risk of an irregular heartbeat.
This is why the combination is flagged as one to avoid. The good news is that your care team has many ways to handle this safely, often by choosing a different medicine for one of them. Please don't stop either drug on your own, just talk with your pharmacist or doctor.
Interaction: Posaconazole is a strong CYP3A4 inhibitor and independently prolongs the QT interval. Sertraline is a CYP3A4 substrate with modest intrinsic QT-prolonging potential.
- Direction: Inhibition of CYP3A4 increases sertraline exposure (neither drug is a prodrug); additive QTc prolongation raises torsade de pointes risk.
- Evidence: Theoretical; TdP cases reported with posaconazole.
- Severity: Labeled contraindicated for posaconazole plus QT-prolonging CYP3A4 substrates.
- Management: Avoid coadministration where possible. If unavoidable, consider an alternative agent, and monitor ECG/QTc and electrolytes (K+, Mg2+) closely per the care team.
What happens
Increased CYP3A4 substrate exposure and an increased risk of QT interval prolongation
Interaction Deep Dive
A potent inhibitor of CYP3A4, posaconazole also has an intrinsic ability to prolong the QT interval, and torsade de pointes has been documented in association with its use. Because combining it with CYP3A4 substrates that likewise prolong the QT interval can raise exposure to those substrates while heightening the likelihood of QT interval prolongation and torsade de pointes, such concurrent use is contraindicated123.
Why it happens (mechanism)
Inhibition of CYP3A4-mediated metabolism by posaconazole; additive QT interval prolongation
How to manage this interaction
Because this pairing is flagged as one to avoid, your care team will usually look at your full medication list and decide the safest path.
- They may choose an alternative antifungal or antidepressant so both drugs aren't used together.
- If both are truly needed, they may monitor you more closely, including heart tracing (ECG) and blood electrolytes.
What you should do: keep taking both exactly as prescribed for now, and don't stop on your own. Contact your pharmacist or prescriber to review this combination. Mention any dizziness, fainting, or a fluttering or racing heartbeat right away.
Management is individual — confirm any change with your pharmacist or prescriber.
Literature reports
1 report — tap to read
Common questions
Can I take Sertraline and Posaconazole together?
Combining posaconazole and sertraline can raise sertraline levels and add up their effects on heart rhythm, so this pairing is generally avoided. Ask your pharmacist or doctor to review it before making any changes. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Sertraline and Posaconazole interaction?
It is rated contraindicated. These should generally not be used together.
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 Posaconazole interaction managed?
Because this pairing is flagged as one to avoid, your care team will usually look at your full medication list and decide the safest path. They may choose an alternative antifungal or antidepressant so both drugs aren't used together. If both are truly needed, they may monitor you more closely, including heart tracing (ECG) and blood electrolytes. What you should do: keep taking both exactly as pr… 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 Posaconazole 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 (3)
- Product Information: NOXAFIL® PowderMix delayed-release oral suspension, posaconazole delayed-release oral suspension. Merck Sharp & Dohme LLC (per FDA), Rahway, NJ, 2026. DailyMed
- Product Information: NOXAFIL® intravenous injection, oral delayed-release tablets, oral suspension, posaconazole intravenous injection, oral delayed-release tablets, oral suspension. Merck Sharp & Dohme LLC (per FDA), Rahway, NJ, 2026. DailyMed
- Product Information: Posaconazole oral delayed-release tablets, posaconazole oral delayed-release tablets. SpecGx LLC (per DailyMed), Webster Groves, MO, 2024. DailyMed
Keep reading about Posaconazole
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.
Check another combination
Our instant two-drug interaction checker is almost here.
Still have questions about this combination?
Every question gets a real answer from a licensed pharmacist — free, and usually within a day.
Ask the pharmacist