Ciprofloxacin and Duloxetine interaction
Ciprofloxacin and Duloxetine: both prescribing labels flag this combination with the strongest language, such as a contraindication, a boxed warning, or an instruction to avoid it.
Do not combine without a prescriber's guidance. The label language below is the strongest FDA uses.
What the FDA labels say
From the Ciprofloxacin label · effective 2026-06-30
Duloxetine Avoid Use Five-fold increase in duloxetine exposure If unavoidable, monitor for duloxetine toxicity.
…syndrome, uncorrected electrolyte imbalance, such as hypokalemia or hypomagnesemia and cardiac disease, such as heart failure, myocardial infarction, or bradycardia), and patients receiving Class IA antiarrhythmic agents (quinidine, procainamide), or Class III antiarrhythmic agents (amiodarone, sotalol), tricyclic antidepressants, macrolides, and antipsychotics.
Drugs Known to Prolong QT Interval Avoid Use Ciprofloxacin may further prolong the QT interval in patients receiving drugs known to prolong the QT interval (for example, class IA or III antiarrhythmics, tricyclic antidepressants, macrolides, antipsychotics) [see Warnings and Precautions ( 5.12 ) and Use in Specific Populations ( 8.5 )].
From the Duloxetine (Cymbalta) label · effective 2025-07-21
Inhibitors of CYP1A2 or Thioridazine : Avoid co-administration with CYMBALTA ( 5.12 )
Potential for Other Drugs to Affect CYMBALTA CYP1A2 Inhibitors — Co-administration of CYMBALTA with potent CYP1A2 inhibitors should be avoided [see Drug Interactions ( 7.1 )] .
Potent inhibitors of CYP1A2 should be avoided ( 7.1 )
The risk of BP decreases may be greater in patients taking concomitant medications that induce orthostatic hypotension (such as antihypertensives) or are potent CYP1A2 inhibitors [see Warnings and Precautions ( 5.12 ) and Drug Interactions ( 7.1 )] and in patients taking CYMBALTA at doses above 60 mg daily.
Inhibitors of CYP1A2 When CYMBALTA 60 mg was co-administered with fluvoxamine 100 mg, a potent CYP1A2 inhibitor, to male subjects (n=14) duloxetine AUC was increased approximately 6-fold, the C max was increased about 2.5-fold, and duloxetine t 1/2 was increased approximately 3-fold.
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Open in the checkerNot medical advice. Interaction Checker quotes FDA label text and NIH fact sheets. Whether an interaction matters for you depends on doses, timing, kidney and liver function, and other conditions. Confirm with a pharmacist or prescriber.