Propranolol with Quinidine Interaction Details

Brand Names Associated with Propranolol

Brand Names Associated with Quinidine

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

Interaction Effect

Hypotension, bradycardia, arrhythmias, and heart failure

Interaction Summary

Coadministration of propranolol and quinidine increases propranolol exposure 2- to 3-fold. Coadministration produces greater degrees of clinical beta blockade and may cause postural hypotension. If coadministration is required, use with caution.

Severity

Moderate

Onset

Rapid

Evidence

Probable

How To Manage Interaction

Coadministration of propranolol and quinidine increases propranolol exposure 2- to 3-fold. Coadministration produces greater degrees of clinical beta blockade and may cause postural hypotension. If coadministration is required, use with caution.

Mechanism Of Interaction

Additive negative inotropic effects; possible inhibition by quinidine of propranolol metabolism

Literature Reports

A) Coadministration of propranolol and quinidine may increase propranolol exposure 2- to 3-fold, which may alter propranolol efficacy and/or toxicity. Coadministration produces greater degrees of clinical beta blockade and may cause postural hypotension .

B) The interaction between quinidine and propranolol in six healthy male volunteers has been studied. Each subject received 80 mg oral propranolol alone and on a separate occasion the same propranolol dose plus 50 mg oral quinidine. Blood and urine samples were collected over a 24-hour period following each treatment. Concentrations of (+)-propranolol and (-)-propranolol and their corresponding metabolites were then measured in both plasma and urine samples. Coadministration of quinidine nearly doubled the propranolol area under the concentration-time curve (AUC), and reduced the clearance of propranolol from 3087 +/- 648 mL/min to 1378 +/- 173 mL/min. The metabolism of propranolol by the 4-hydroxylation pathway was considerably reduced by quinidine, from 678 +/- 246 mL/min to 56 +/- 11 mL/min. Quinidine exerted a stereoselective effect on propranolol concentration, resulting in a greater mean AUC for (+)-propranolol than for (-)-propranolol. Coadministration also resulted in increased beta-blockade, noted by a reduction in exercise heart rate and prolongation of the QTc and PR intervals .

C) In a study of five healthy adults, the pharmacokinetic interaction between propranolol and quinidine was studied. Each subject received 80 mg propranolol every six hours for three days, after which propranolol was discontinued. After a washout period of at least seven days, subjects received quinidine 200 mg every six hours for three days. After the third day, propranolol 80 mg every six hours was added. Multiple blood samples were taken after the third day of each treatment regimen. For both propranolol and quinidine, the average steady-state plasma concentrations were unchanged during coadministration. The maximum propranolol and quinidine concentrations and time to maximum concentrations were also unchanged .

D) A 65-year-old man treated with propranolol 40 mg four times daily for several years for angina pectoris had quinidine 200 mg four times daily added to his therapeutic regimen due to ventricular ectopic beats. The patient then experienced symptoms of orthostatic hypotension, noted by the inability to stand upright without feeling dizzy or faint. In order to determine if the patient's symptoms were drug-related, the patient's therapy was changed to quinidine alone, and after one month was switched to propranolol alone. After an additional month, all therapy was discontinued. During coadministration of the two drugs, the blood pressure decrease upon standing was greater than blood pressure decreases when quinidine alone or propranolol alone was given. The authors proposed that this orthostatic fall in blood pressure was due to an additive effect of quinidine blockade of alpha receptors and propranolol beta-blockade .

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.

Quinidine Overview

• Quinidine is used to treat certain types of irregular heartbeats. Quinidine is in a class of medications called antiarrhythmic medications. It works by making your heart more resistant to abnormal activity.

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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.