Cyclophosphamide and Succinylcholine: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Cyclophosphamide
Succinylcholine
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
An increased risk of potentiated succinylcholine efficacy
Interaction Deep Dive
Cyclophosphamide may depress cholinesterase activity by as much as 70%. There is potential for prolonged succinylcholine-induced apnea12. Cyclophosphamide is an irreversible inhibitor of plasma cholinesterase, thereby prolonging the effects of succinylcholine 3.
Why it happens (mechanism)
Reduced plasma cholinesterase activity
Common questions
Can I take Cyclophosphamide and Succinylcholine together?
An increased risk of potentiated succinylcholine efficacy Always confirm with your pharmacist or prescriber before making any change.
How serious is the Cyclophosphamide and Succinylcholine 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 "theoretical". Predicted from the drugs' pharmacology; not yet confirmed in people.
Questions for your pharmacist
- Does my dose of Cyclophosphamide or Succinylcholine 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 (3)
- Walker IR, Zapf PW, & Mackay IR: Cyclophosphamide, cholinesterase and anaesthesia. N Z Med J 1972; 2:247-251. PubMed
- Dillman JB: Safe use of succinylcholine during repeated anesthetics in a patient treated with cyclophosphamide. Anesth Analg 1987; 66:3510-353. DOI
- Viby-Mogensen J: Cholinesterase and succinylcholine. Dan Med Bull 1983; 30:129-150.
Keep reading about Cyclophosphamide
Keep reading about Succinylcholine
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:
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