Clindamycin and Pacritinib: Interaction Details
AI-assisted, pharmacist-reviewed · AI content regenerated Jul 11, 2026 · Source data updated Jul 1, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Clindamycin
Pacritinib
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.
You've been prescribed clindamycin (an antibiotic) along with pacritinib (Vonjo). Here's the plain-English version: pacritinib can speed up how your body breaks down clindamycin. That means there may be less clindamycin in your system than expected, which could make the antibiotic work less well against your infection.
The good news is this is very manageable. Your care team can keep a closer eye on how well your infection is responding, and they can adjust your clindamycin dose if needed. Please don't change anything on your own. Just keep taking both as directed and let your doctor or pharmacist know how you're feeling.
Effect: Pacritinib is a CYP3A4 inducer and clindamycin is partly metabolized by CYP3A4. Coadministration may increase clindamycin clearance, lowering exposure (AUC/Cmax) and potentially reducing antimicrobial efficacy.
Direction: Reduced clindamycin effect (neither drug is a prodrug here).
- Mechanism: Induction of CYP3A4-mediated clindamycin metabolism.
- Onset: Unspecified (enzyme induction is typically delayed, days to weeks).
- Evidence: Probable; severity major.
- Management: Monitor clinical/microbiologic response more closely. Clindamycin dose may need individualized adjustment. Consider an alternative agent if response is inadequate.
What happens
Reduced CYP3A4 substrate with NTI exposure and reduced efficacy of CYP3A4 substrate with NTI
Interaction Deep Dive
When pacritinib, which acts as a CYP3A4 inducer, is given together with CYP3A4 substrates that have a narrow therapeutic index (NTI), the exposure to those NTI CYP3A4 substrates may decrease, and their efficacy may consequently be diminished as well. During concurrent use of pacritinib with such NTI CYP3A4 substrates, the efficacy of the CYP3A4 substrate should be monitored more often. Adjusting the dose of the CYP3A4 substrates with NTI may become necessary1.
Why it happens (mechanism)
Induction of CYP3A4-substrate metabolism by pacritinib
How to manage this interaction
Your team can manage this by watching how well the clindamycin is working and adjusting as needed.
- Keep taking both exactly as prescribed unless your doctor tells you otherwise.
- Your care team may monitor your response more closely to make sure the infection is clearing.
- Your clindamycin dose may need to be adjusted and individualized by your team, since pacritinib can lower its levels.
- Tell your pharmacist or doctor if your symptoms aren't improving or seem to be getting worse.
Management is individual — confirm any change with your pharmacist or prescriber.
Literature reports
1 report — tap to read
a) In a drug interaction study, giving pacritinib at a dose of 200 mg twice daily together with midazolam (a CYP3A4 substrate) may lead to a decrease in midazolam Cmax and AUC by 0.40-fold and 0.40-fold respectively 1.
Common questions
Can I take Clindamycin and Pacritinib together?
Pacritinib can speed up the breakdown of clindamycin, possibly making the antibiotic less effective, so your team may monitor your response closely and adjust the clindamycin dose if needed. Keep taking both as prescribed and report any lack of improvement. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Clindamycin and Pacritinib 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 Clindamycin and Pacritinib interaction managed?
Your team can manage this by watching how well the clindamycin is working and adjusting as needed. Keep taking both exactly as prescribed unless your doctor tells you otherwise. Your care team may monitor your response more closely to make sure the infection is clearing. Your clindamycin dose may need to be adjusted and individualized by your team, since pacritinib can lower its levels. Tell your… Management is individual — always follow your own care team's guidance.
How strong is the evidence for this interaction?
The evidence is graded "probable". Good supporting evidence, though not definitively proven.
From our Q&A
Real reader questions about these medications, each personally answered by our pharmacist:
Questions for your pharmacist
- Does my dose of Clindamycin or Pacritinib 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: VONJO(R) oral capsules, pacritinib oral capsules. CTI BioPharma Corp (per FDA), Seattle, WA, 2024. DailyMed
Keep reading about Clindamycin
Keep reading about Pacritinib
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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