Praziquantel and Dexamethasone Injection: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Praziquantel
Dexamethasone 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
Significantly decreased praziquantel plasma concentrations
Interaction Deep Dive
The concomitant use of praziquantel with strong CYP inducers is contraindicated. In one study in healthy subjects, a single oral dose of praziquantel 40 mg/kg administered with multiple doses of oral rifampin 600 mg/day for 5 days resulted in undetectable praziquantel plasma concentrations in 7 out of 10 subjects. Although not formally studied, coadministration with dexamethasone, a strong CYP enzyme inducer, may result in a similar interaction1. Consider prescribing an alternative agent for treating schistosomiasis in patients receiving dexamethasone. However, if praziquantel therapy is warranted, a 4-week washout period is recommended before initiating praziquantel therapy in patients receiving rifampin (another strong CYP inducer) 1. Although not evaluated with dexamethasone, consider employing a similar washout period if praziquantel therapy is necessary.
Why it happens (mechanism)
Induction of CYP-mediated praziquantel metabolism by dexamethasone
Common questions
Can I take Praziquantel and Dexamethasone Injection together?
Significantly decreased praziquantel plasma concentrations Always confirm with your pharmacist or prescriber before making any change.
How serious is the Praziquantel and Dexamethasone Injection interaction?
It is rated contraindicated. These should generally not be used together.
How quickly could this interaction happen?
The documented onset is "delayed". Effects tend to build up gradually over days to weeks.
How strong is the evidence for this interaction?
The evidence is graded "theoretical". Predicted from the drugs' pharmacology; not yet confirmed in people.
Questions for your pharmacist
- Does my dose of Praziquantel or Dexamethasone 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 (1)
- Product Information: BILTRICIDE(R) oral tablets, praziquantel oral tablets. Merck & Co,Inc, Whitehouse Station, NJ, 2010. DailyMed
Keep reading about Praziquantel
Keep reading about Dexamethasone Injection
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