Digoxin with Quinine Interaction Details
Brand Names Associated with Digoxin
- Cardoxin®
- Digitek®
- Digoxin
- Lanoxicaps®
- Lanoxin®
Brand Names Associated with Quinine
- Qualaquin®
- Quinine
Medical Content Editor Dr. Brian Staiger, PharmD
Last updated
Jan 08, 2024
Interaction Effect
Increased plasma concentrations of digoxin
Interaction Summary
Concomitant administration of quinine and digoxin has increased digoxin AUC by 33%, digoxin levels by 25% to 40%, and digoxin half-life from 30 hours to approximately 40 to 50 hours . Concomitant administration of quinine and IV digoxin has increased digoxin AUC by 34% to 38% . Measure digoxin concentrations prior to initiation of concurrent use. Reduce the digoxin dose by approximately 15% to 30% or modify the dosing frequency. Continue monitoring digoxin plasma concentration levels .
Severity
Major
Onset
Unspecified
Evidence
Probable
How To Manage Interaction
Concomitant use of digoxin and quinine may increased digoxin exposure or plasma concentrations . Measure digoxin concentrations prior to initiation of concurrent use. Reduce the digoxin dose by approximately 15% to 30% or modify the dosing frequency. Continue monitoring digoxin plasma concentration levels .
Mechanism Of Interaction
Unknown
Literature Reports
A) In pharmacokinetic studies, concomitant administration of quinine and digoxin increased digoxin AUC by 33% . Concomitant administration of quinine and IV digoxin increased digoxin AUC by 34% to 38% .
B) Since quinine is the levorotory stereoisomer of quinidine, its interaction with digoxin has been studied. The results indicate that the effect of quinidine on digoxin renal clearance is non-stereospecific. Quinidine and quinine may have the same effect on digoxin by inhibiting the tubular secretion and thus decreasing renal clearance of digoxin . Quinine has also been shown to decrease biliary secretory clearance of digoxin .
C) The effect of quinine on the pharmacokinetics of digoxin was studied in 7 healthy male volunteers. Each subject received an oral loading dose of digoxin 1 mg over a 24-hour period, followed by an oral maintenance dose of 0.1875 mg twice daily. After 2 weeks of digoxin therapy, quinine sulfate 250 mg once daily was initiated for a 1-week period. The quinine dose was then increased to 750 mg daily for an additional week. Results showed that quinine increased the digoxin plasma concentration from 0.64 nanogram/mL (ng/mL; 0.82 nanomol/L) prior to quinine therapy to 0.8 ng/mL (1.02 nanomol/L) during quinine 250 mg administration and 0.85 ng/mL (1.088 nanomol/L) during quinine 750 mg administration. The renal clearance of digoxin fell from 181 mL/min during control to 174 mL/min during quinine 250 mg treatment and 171 mL/min during quinine 750 mg treatment. CrCl and renal digoxin clearance were not altered during quinine and digoxin coadministration .
D) Six subjects (four healthy and two hospitalized) were given an IV dose of digoxin 1 mg over 10 minutes. Four days later, quinine sulfate 200 mg every eight hours was administered for 4 days before and 4 days after a second dose of IV digoxin 1 mg. Quinine decreased the digoxin total body clearance by 26% (from 2.98 mL/min/kg to 2.22 mL/min/kg). The half-life of digoxin was increased from 34.2 hours to 51.8 hours, representing a 32% decrease in the digoxin elimination rate constant. Digoxin Vd and renal clearance were unaltered. These results suggest that quinine alters the metabolism or biliary secretion of digoxin, thereby reducing digoxin total body clearance .
Digoxin Overview
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Digoxin is used to treat heart failure and abnormal heart rhythms (arrhythmias). It helps the heart work better and it helps control your heart rate.
Quinine Overview
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Quinine is used alone or with other medications to treat malaria (a serious or life-threatening illness that is spread by mosquitos in certain parts of the world). Quinine should not be used to prevent malaria. Quinine is in a class of medications called antimalarials. It works by killing the organisms that cause malaria.
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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:
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.