Irinotecan Injection and Citalopram: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Citalopram
Irinotecan 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
An increased risk of myopathy or rhabdomyolysis
Interaction Deep Dive
Rhabdomyolysis has occurred in a patient after concomitant use of irinotecan, a camptothelin which acts primarily as a topoisomerase I inhibitor, and citalopram, a selective serotonin reuptake inhibitor (SSRI)1.
Why it happens (mechanism)
Inhibition of cytochrome P4503A4-mediated metabolism of citalopram by irinotecan
Literature reports
1 report — tap to read
a) Citalopram interacted with irinotecan to produce rhabdomyolysis in a 74-year-old white male. He presented with 2-month history of fatigue, weight loss, and decreased appetite and was diagnosed with adenocarcinoma. Three days before admission, he was treated with irinotecan in the outpatient clinic. On the day of admission, he presented to the emergency department complaining of weakness and pain. His medical history was significant for coronary artery disease, dyslipidemia, and chronic obstructive lung disease. He was taking enalapril, alprazolam, simvastatin, citalopram, nitroglycerin and aspirin (no dosages were specified). Physical examination on admission was remarkable for generalized weakness and absence of focal neurologic signs. He had diffuse muscle tenderness. At admission his creatine kinase (CK) level was 7400 units/liter (U/L) (49-397 U/L). All medications were discontinued following a diagnosis of rhabdomyolysis. The CK decreased to 5542 U/L. The patient became depressed and citalopram 20 mg one time only was administered. The CK subsequently increased to 13529 U/L, and myoglobin was 27579 ng/mL. After citalopram was discontinued the CK and myoglobin decreased again during the next 5 days. The patient eventually regained his strength and was able to ambulate without pain upon discontinuation of citalopram 1.
Common questions
Can I take Irinotecan Injection and Citalopram together?
An increased risk of myopathy or rhabdomyolysis Always confirm with your pharmacist or prescriber before making any change.
How serious is the Irinotecan Injection and Citalopram interaction?
It is rated moderate. Can be significant — usually manageable with monitoring.
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 "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 Irinotecan Injection or Citalopram 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 (1)
- Richards S, Umbreit J, Fanucchi M, et al: Selective serotonin reuptake inhibitor-induced rhabdomyolysis associated with irinotecan. South Med J 2003; 95(5):1031-1033. PubMed
Keep reading about Citalopram
Keep reading about Irinotecan Injection
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