Furosemide with Theophylline Interaction Details

Brand Names Associated with Furosemide

Brand Names Associated with Theophylline

Medical Content Editor Dr. Brian Staiger, PharmD
Last updated Nov 10, 2023

Interaction Effect

Altered theophylline concentrations

Interaction Summary

Concomitant furosemide and theophylline therapy has been reported to produce increases or decreases in theophylline serum concentrations. In four premature newborns, concurrent use of theophylline and furosemide resulted in decreased theophylline peak concentration. If agents are administered at least two hours apart, no interactions have been reported to occur .

Severity

Minor

Onset

Rapid

Evidence

Theoretical

How To Manage Interaction

Theophylline serum concentrations should be closely monitored when furosemide is added, discontinued, or when dosing changes occur. Dosing adjustments of theophylline may be necessary.

Mechanism Of Interaction

Unknown

Literature Reports

A) Administration of a single 40 mg intravenous bolus of furosemide in patients stabilized at steady-state on continuous intravenous aminophylline infusion resulted in an increase (average, 2.9 mcg/mL (16 mcmol/L)) in serum theophylline concentrations (range, 0.5 to 5.5 mcg/mL (3 to 30.5 mcmol/L)). Urine volumes increase by an average of 995 mL above baseline . However, one study has suggested that furosemide administration can significantly reduce theophylline serum concentrations in asthmatic patients . Contrary to previous reports,  reported no significant interaction between theophylline and furosemide in healthy volunteers. Two doses of furosemide 20 mg at 4-hour intervals did not influence steady-state theophylline plasma concentrations. In this study, furosemide induced a moderate diuresis, as well as a reduction in renal clearance, which may explain the lack of effects observed on theophylline serum concentrations.

Furosemide Overview

• Furosemide is used alone or in combination with other medications to treat high blood pressure. Furosemide is used to treat edema (fluid retention; excess fluid held in body tissues) caused by various medical problems, including heart, kidney, and liver disease. Furosemide is in a class of medications called diuretics ('water pills'). It works by causing the kidneys to get rid of unneeded water and salt from the body into the urine.

• 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.

Theophylline Overview

• Theophylline is used to prevent and treat wheezing, shortness of breath, and chest tightness caused by asthma, chronic bronchitis, emphysema, and other lung diseases. It relaxes and opens air passages in the lungs, making it easier to breathe.

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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.