Fluoxetine with Propranolol Interaction Details

Brand Names Associated with Fluoxetine

Brand Names Associated with Propranolol

Medical Content Editor Dr. Brian Staiger, PharmD
Last updated Nov 15, 2023

Interaction Effect

Increased propranolol exposure and an increased risk of propranolol toxicity, including complete heart block

Interaction Summary

FLUoxetine (a potent CYP2D6 inhibitor) may increase the exposure of drugs that are metabolized by CYP2D6, including propranolol. Increased propranolol exposure may increase the risk of propranolol toxicity , including complete heart block. One case report described a man who developed complete heart block 2 weeks after FLUoxetine was added to propranolol therapy . Use caution when coadministering FLUoxetine with propranolol .

Severity

Major

Onset

Unspecified

Evidence

Probable

How To Manage Interaction

Use caution when coadministering FLUoxetine (a potent CYP2D6 inhibitor) with propranolol (a CYP2D6 substrate), as coadministration may increase propranolol exposure and increase the risk of propranolol toxicity , including complete heart block .

Mechanism Of Interaction

Inhibition of CYP2D6-mediated metabolism of propranolol by FLUoxetine

Literature Reports

A) A 53-year-old man experienced a loss of consciousness 2 weeks after FLUoxetine 20 mg daily was prescribed for depression. Other medications included propranolol 40 mg twice daily for anxiety. He had no previous cardiac history. An ECG revealed a complete heart block, and FLUoxetine and propranolol were both discontinued. Two days later, the patient reverted to sinus rhythm with a heart rate of 60 beats per minute. The heart block was attributed to the FLUoxetine-propranolol combination, since sinus rhythm returned 2 days after the discontinuation of FLUoxetine, and the patient had no previous complications from propranolol therapy. Because 5-hydroxytryptamine (5-HT) receptors are located in the atrium of the heart, FLUoxetine may have potentiated the action of 5-HT, causing impaired atrioventricular conduction .

Fluoxetine Overview

• Fluoxetine is used to treat depression, obsessive-compulsive disorder (bothersome thoughts that won't go away and the need to perform certain actions over and over), some eating disorders, and panic attacks (sudden, unexpected attacks of extreme fear and worry about these attacks). Fluoxetine is also used to relieve the symptoms of premenstrual dysphoric disorder, including mood swings, irritability, bloating, and breast tenderness. It is also used along with olanzapine (Zyprexa) to treat depression that did not respond to other medications and episodes of depression in people with bipolar I disorder (manic-depressive disorder; a disease that causes episodes of depression, episodes of mania, and other abnormal moods). Fluoxetine is in a class of medications called selective serotonin reuptake inhibitors (SSRIs). It works by increasing the amount of serotonin, a natural substance in the brain that helps maintain mental balance.

Propranolol Overview

• Propranolol is used to treat high blood pressure, irregular heart rhythms, pheochromocytoma (tumor on a small gland near the kidneys), certain types of tremor, and hypertrophic subaortic stenosis (a heart muscle disease). It is also used to prevent angina (chest pain), migraine headaches, and to improve survival after a heart attack. Propranolol is in a class of medications called beta blockers. It works by relaxing blood vessels and slowing heart rate to improve blood flow and decrease blood pressure.

• High blood pressure is a common condition and when not treated, can cause damage to the brain, heart, blood vessels, kidneys and other parts of the body. Damage to these organs may cause heart disease, a heart attack, heart failure, stroke, kidney failure, loss of vision, and other problems. In addition to taking medication, making lifestyle changes will also help to control your blood pressure. These changes include eating a diet that is low in fat and salt, maintaining a healthy weight, exercising at least 30 minutes most days, not smoking, and using alcohol in moderation.

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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:

• Gold Standard Drug Database
• Micromedex
• Lexicomp
• DrugBank

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.