Caspofungin Injection and Rifampin: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Rifampin
Caspofungin 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 caspofungin plasma levels
Interaction Deep Dive
Concomitant use of caspofungin with rifampin, a potent CYP3A4 inducer, may result in significant reductions in caspofungin plasma levels1. Concomitant administration of caspofungin with rifampin appeared to transiently inhibit caspofungin plasma clearance prior to producing a significant reduction in trough caspofungin plasma concentrations 2. Rifampin reduced caspofungin trough concentrations by 30%. Adult patients receiving rifampin and caspofungin concomitantly should receive 70 mg of caspofungin daily and pediatric patients should receive 70 mg/m(2) daily (not to exceed 70 mg/day) 1.
Why it happens (mechanism)
Rifampin-mediated induction of caspofungin plasma clearance
Literature reports
2 reports — tap to read
a) Concomitant administration of caspofungin with rifampin appeared to transiently inhibit caspofungin plasma clearance prior to producing a significant reduction in trough caspofungin plasma concentrations. In the first of a pair of open-label, randomized controlled studies, healthy men were assigned to receive 14-day regimens of intravenous caspofungin 50 mg once daily, administered concurrently with or without a once-daily oral dose of rifampin 600 mg (n=10, both treatment groups). In the second study, healthy men received monotherapy with intravenous caspofungin 50 mg (n=12) or received a 28-day oral regimen of rifampin 600 mg once daily, augmented on days 15-28 with IV caspofungin 50 mg once daily. Concurrent initiation of caspofungin with rifampin produced significant elevations in caspofungin AUC and trough plasma concentrations (C-24h) by 61% and 170%, respectively, in the first 24 hours of concurrent dosing. However, coadministration values for both AUC and C-24h declined from day 2 and thereafter through day 14, at which time caspofungin trough plasma concentrations were below control group C-24h values. Conversely, when subjects were pretreated with a 14-day monotherapy regimen of rifampin 600 mg daily, the subsequent addition of caspofungin produced a significant reduction in mean C-24h caspofungin plasma values, compared with controls (29% and 31% mean reductions, days 1 and 14, respectively). The reductions in caspofungin trough concentrations were sustained throughout the 14-day study period. The authors propose that rifampin affects caspofungin clearance by the induction of uptake transporters, rather than via metabolic enzyme induction 2.
b) Combined use of caspofungin and rifampin reduced caspofungin trough levels by 30% 1.
Common questions
Can I take Caspofungin Injection and Rifampin together?
Reduced caspofungin plasma levels Always confirm with your pharmacist or prescriber before making any change.
How serious is the Caspofungin Injection and Rifampin interaction?
It is rated moderate. Can be significant — usually manageable with monitoring.
How quickly could this interaction happen?
The documented onset is "rapid". Effects can appear quickly, often within about 24 hours of combining the drugs.
How strong is the evidence for this interaction?
The evidence is graded "established". Well documented — supported by controlled studies or strong clinical data.
Questions for your pharmacist
- Does my dose of Caspofungin Injection or Rifampin 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 anything you'd monitor while I'm on both?
References (2)
- Product Information: CANCIDAS(R) intravenous injection, caspofungin acetate intravenous injection. Merck Sharp & Dohme Corp. (per FDA), Whitehouse Station, NJ, 2016. DailyMed
- Stone JA, Migoya EM, Hickey L, et al: Potential for interactions between caspofungin and nelfinavir or rifampin. Antimicrob Agents Chemother 2004; 48(11):4306-4314. PubMed
Keep reading about Rifampin
Keep reading about Caspofungin Injection
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