Amiodarone
The antiarrhythmic agent amiodarone is often used to treat ventricular tachycardia and fibrillation; however, because of this drug's narrow therapeutic index, organ toxicity has occurred with amiodarone overexposure. Matuskova and colleagues demonstrated that rats administered a probiotic containing a particular strain of E coli Nissle 1917 experienced plasma amiodarone concentrations up to 1.4 times higher than concentrations in control rats receiving either saline or the nonprobiotic strain of E coli.[17] The exact cause of the increased bioavailability with this specific organism has not been identified, but increased drug absorption into systemic circulation is a plausible explanation. Theories for this increased absorption include 1) a decrease in local pH mediated by the microorganisms that ionizes and facilitates amiodarone's absorption through the mucosal layer and 2) an increase in the expression of a particular cellular membrane transporter that mediates the uptake of amiodarone.[17] As with warfarin, the narrow therapeutic index and adverse drug reactions of amiodarone make it crucial to better understand the influence of the microbiota on this drug.
US Pharmacist. 2023;48(2):18-22. © 2023 Jobson Publishing
