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.

Major

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

Major

Duloxetine Avoid Use Five-fold increase in duloxetine exposure If unavoidable, monitor for duloxetine toxicity.

Drug interactionsnames DuloxetineView label on DailyMed
Moderate

…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.

Warnings and precautionsby drug classView label on DailyMed
Moderate

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 )].

Drug interactionsby drug classView label on DailyMed

From the Duloxetine (Cymbalta) label · effective 2025-07-21

Major

Inhibitors of CYP1A2 or Thioridazine : Avoid co-administration with CYMBALTA ( 5.12 )

Warnings and precautionsby drug classView label on DailyMed
Major

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 )] .

Warnings and precautionsby drug classView label on DailyMed
Major

Potent inhibitors of CYP1A2 should be avoided ( 7.1 )

Drug interactionsby drug classView label on DailyMed
Moderate

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.

Warnings and precautionsby drug classView label on DailyMed
Moderate

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.

Drug interactionsby drug classView label on DailyMed

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Not 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.