Buspirone with Rifampin Interaction Details

Brand Names Associated with Buspirone

Brand Names Associated with Rifampin

Medical Content Editor Dr. Brian Staiger, PharmD
Last updated Mar 06, 2024

Interaction Effect

Reduced anxiolytic effects of busPIRone

Interaction Summary

In a study to determine the effects of rifampin on busPIRone pharmacokinetics and pharmacodynamics, rifampin significantly induced the metabolism of busPIRone, resulting in reduced anxiolytic effects. Rifampin is a potent inducer of cytochrome P450 3A4 enzymes, and busPIRone is suspected of being a substrate of CYP3A4[1].

Severity

Moderate

Onset

Rapid

Evidence

Probable

How To Manage Interaction

Monitor patients receiving busPIRone and rifampin for busPIRone efficacy. Doses of busPIRone may need to be increased when rifampin is coadministered.

Mechanism Of Interaction

Induction of cytochrome P450 3A4-mediated first-pass metabolism of busPIRone

Literature Reports

A) Ten healthy volunteers participated in a randomized, placebo-controlled, cross-over study design to determine the effects of rifampin on the pharmacokinetics and pharmacodynamics of busPIRone. Subjects ingested rifampin 600 mg or matching placebo once daily for five days, and then received busPIRone 30 mg as a single oral dose on day 6. Although the normal dose of busPIRone is 5 mg to 10 mg, 30 mg was used in this study to allow more accurate determinations of plasma busPIRone concentrations after rifampin administration. Maximum concentrations (Cmax) of busPIRone averaged 6.6 ng/mL (17 nanomoles/L (nmol/L)) during the placebo phase, but decreased to 0.84 ng/mL (2.2 nmol/L) following rifampin pretreatment. Time to Cmax (tmax) also decreased from 1.5 hours to 0.5 hours. Half-life of busPIRone was reduced from 2.8 hours to 1.3 hours in the rifampin phase, and the area under the concentration-time curve (AUC) also decreased from 22 ng/mL/h to 1.64 ng/mL/h. Results of psychomotor tests, including the digit symbol substitution test, critical flicker fusion test, postural sway test measures, and subjective drowsiness and overall drug effect, revealed that rifampin greatly decreased the sedative and anxiolytic effect of busPIRone. These results were consistent with what would be expected from the pharmacokinetic changes seen in busPIRone following rifampin pretreatment [1].

References

1 ) Lamberg TS, Kivisto KT, & Neuvonen PJ: Concentrations and effects of buspirone are considerably reduced by rifampicin. Br J Clin Pharmacol 1998; 45:381-385.

Buspirone Overview

• Buspirone is used to treat anxiety disorders or in the short-term treatment of symptoms of anxiety. Buspirone is in a class of medications called anxiolytics. It works by changing the amounts of certain natural substances in the brain.

Rifampin Overview

• Rifampin is used with other medications to treat tuberculosis (TB; a serious infection that affects the lungs and sometimes other parts of the body). Rifampin is also used to treat some people who have Neisseria meningitidis (a type of bacteria that can cause a serious infection called meningitis) infections in their noses or throats. These people have not developed symptoms of the disease, and this treatment is used to prevent them from infecting other people. Rifampin should not be used to treat people who have developed symptoms of meningitis. Rifampin is in a class of medications called antimycobacterials. It works by killing the bacteria that cause infection.

• Antibiotics such as rifampin will not work for colds, flu, or other viral infections. Using antibiotics when they are not needed increases your risk of getting an infection later that resists antibiotic treatment.

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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.