Olanzapine with Enoxacin Interaction Details
Brand Names Associated with Olanzapine
- Olanzapine
- Symbyax® (as a combination product containing Fluoxetine, Olanzapine )
- Zyprexa®
- Zyprexa® Zydis
Medical Content Editor Dr. Brian Staiger, PharmD
Last updated
Dec 03, 2023
Interaction Effect
Increased OLANZapine exposure and an increased risk of OLANZapine-related adverse effects
Interaction Summary
Concomitant use of OLANZapine (CYP1A2 substrate) with a strong CYP1A2 inhibitor increases OLANZapine exposure, which may increase the risk of adverse reactions. Consider reducing OLANZapine dosage when coadministered with strong CYP1A2 inhibitors. Literature reports have demonstrated elevated OLANZapine plasma levels and OLANZapine-induced side effects or intoxication when used with fluvoxaMINE, a strong CYP1A2 inhibitor .
Severity
Major
Onset
Unspecified
Evidence
Theoretical
How To Manage Interaction
Concomitant use of OLANZapine (a CYP1A2 substrate) with enoxacin (a strong CYP1A2 inhibitor) has increased OLANZapine exposure, which may increase the risk of OLANZapine-related adverse reactions. Consider reducing the OLANZapine dosage when used concomitantly with strong CYP1A2 inhibitors.
Mechanism Of Interaction
Inhibition of CYP1A2-mediated OLANZapine metabolism
Literature Reports
A) FluvoxaMINE, a strong CYP1A2 inhibitor, decreased the clearance of OLANZapine. A mean increase in OLANZapine Cmax 54% was observed in female nonsmokers and 77% in male smokers. The mean increase in OLANZapine AUC in female nonsmokers and male smokers is 52% and 108%, respectively .
B) A patient with schizophrenia and depression experienced elevated OLANZapine plasma levels during coadministration of fluvoxaMINE for several months. She appeared to move rigidly, had a slight tremor of both hands, and mydriasis. OLANZapine concentration was 120 mcg/L and fluvoxaMINE concentration was 70 mcg/L. OLANZapine was decreased from 15 to 5 mg/day. Fourteen days after the last decrease in dose, OLANZapine plasma level was 38 mcg/L; tremor and rigidity disappeared, but mydriasis persisted. FluvoxaMINE was replaced by PARoxetine and OLANZapine concentration decreased further to 22 mcg/L .
C) Eight patients with chronic schizophrenia taking stable doses of OLANZapine 10 to 20 mg/day had fluvoxaMINE 100 mg/day added at the start of the study (week 0) and continued for 8 weeks. OLANZapine concentrations increased 1.58-fold from week 0 to week 1, 1.42-fold from week 0 to week 4, and 1.81-fold from week 0 to week 8. Percentage change from week 0 to week 8 ranged from 12% to 112%. Mean concentrations of the N-demethyl OLANZapine metabolite were not significantly changed. The ratio of increase in OLANZapine concentrations from week 0 to week 8 did not correlate significantly with fluvoxamine serum levels. Coadminister OLANZapine and fluvoxaMINE cautiously; control clinically and with therapeutic drug monitoring to avoid OLANZapine-induced side effects or intoxication .
Olanzapine Overview
-
Olanzapine is used to treat the symptoms of schizophrenia (a mental illness that causes disturbed or unusual thinking, loss of interest in life, and strong or inappropriate emotions) in adults and teenagers 13 years of age and older. It is also used to treat bipolar disorder (manic depressive disorder; a disease that causes episodes of depression, episodes of mania, and other abnormal moods) in adults and teenagers 13 years of age and older. Olanzapine is in a class of medications called atypical antipsychotics. It works by changing the activity of certain natural substances in the brain.
Return To Our Drug Interaction Homepage
Feedback, Question Or Comment About This Information?
Ask Dr. Brian Staiger, PharmD, our medical editor, directly! He's always more than happy to assist.
Definitions
Severity Categories
Contraindicated
These drugs, generally, should not be used together simultaneously due to the high risk of severe adverse effects. Combining these medications can lead to dangerous health outcomes and should be strictly avoided unless otherwise instructed by your provider.
Major
This interaction could result in very serious and potentially life-threatening consequences. If you are taking this drug combination, it is very important to be under close medical supervision to minimize severe side effects and ensure your safety. It may be necessary to change a medication or dosage to prevent harm.
Moderate
This interaction has the potential to worsen your medical condition or alter the effectiveness of your treatment. It's important that you are monitored closely and you potentially may need to make adjustments in your treatment plan or drug dosage to maintain optimal health.
Minor
While this interaction is unlikely to cause significant problems, it could intensify side effects or reduce the effectiveness of one or both medications. Monitoring for changes in symptoms and your condition is recommended, and adjustments may be made if needed to manage any increased or more pronounced side effects.
Onset
Rapid: Onset of drug interaction typically occurs within 24 hours of co-administration.
Delayed: Onset of drug interaction typically occurs more than 24 hours after co-administration.
Evidence
Level of documentation of the interaction.
Established: The interaction is documented and substantiated in peer-reviewed medical literature.
Theoretical: This interaction is not fully supported by current medical evidence or well-documented sources, but it is based on known drug mechanisms, drug effects, and other relevant information.
How To Manage The Interaction
Provides a detailed discussion on how patients and clinicians can approach the identified drug interaction as well as offers guidance on what to expect and strategies to potentially mitigate the effects of the interaction. This may include recommendations on adjusting medication dosages, altering the timing of drug administration, or closely monitoring for specific symptoms.
It's important to note that all medical situations are unique, and management approaches should be tailored to individual circumstances. Patients should always consult their healthcare provider for personalized advice and guidance on managing drug interactions effectively.
Mechanism Of Interaction
The theorized or clinically determined reason (i.e., mechanism) why the drug-drug interaction occurs.
Disclaimer: The information provided on this page is for informational purposes only and should not be considered medical advice. Always consult with a qualified healthcare professional regarding your specific circumstances and medical conditions.
Where Does Our Information Come From?
Information for our drug interactions is compiled from several drug compendia, including:
The prescribing information for each drug, as published on DailyMED, is also used.
Individual drug-drug interaction detail pages contain references specific to that interaction. You can click on the reference number within brackets '[]' to see what reference was utilized.
The information posted is fact-checked by HelloPharmacist clinicians and reviewed quarterly.