Amoxicillin With Zestoretic Interaction
In our latest question and answer, the pharmacist discusses whether or not amoxicillin interacts with Zestoretic.
I was just started on amoxicillin for a UTI. I checked a drug interaction website for any interaction. It said that there is a significant interaction with my blood pressure medication Zestoretic 10/12.5. Is this correct?
Nov 29, 2022- Amoxicillin and Zestoretic are safe to take together and Zestoretic will not reduce how well amoxicillin works for your infection. The interaction you may have read about is likely only theoretical based on how diuretics work in the body, but this specific combination has not been shown to cause actual problems. Amoxicillin is rapidly absorbed and does not rely on kidney reabsorption to be effective, which is why the diuretic in Zestoretic does not interfere with it.
Answer
I'm not sure where you read of a drug interaction between amoxicillin and Zestoretic (lisinopril; hydrochlorothiazide), but they are considered safe to take together. Zestoretic will not reduce the effectiveness of amoxicillin in treating your urinary tract infection.
If you did read about an interaction, I imagine it would be only a theoretical one based on the fact that Zestoretic contains the diuretic hydrochlorothiazide.
Diuretics Interact With Some Drugs
Diuretics like hydrochlorothiazide cause diuresis (increased production of urine from the kidney) which, in theory, increases the excretion rate of some drugs that are predominately eliminated via the kidneys.
Additionally, some drugs are reabsorbed via the kidneys and diuresis would decrease this reabsorption, leading to an overall reduction in drug levels.
So, diuretics absolutely do interact with some drugs in several different ways, such as increased excretion and decreased reabsorption. However, this doesn't appear to be an issue when it comes to amoxicillin.
Amoxicillin With Diuretics
I'm guessing whatever interaction checker you looked at automatically showed an interaction between amoxicillin and Zestoretic simply based on the fact that you were checking a combination of a diuretic (hydrochlorothiazide) with a drug (amoxicillin) that is primarily excreted via the kidney.
However, taking amoxicillin with hydrochlorothiazide has not been shown to affect drug concentrations, or how well it works.
Amoxicillin is rapidly absorbed after taking a dose, and peak concentrations are reached after only 1 to 2 hours. It doesn't rely on kidney reabsorption to work and, in those with normal kidney function, more than 60% of an amoxicillin dose is excreted unchanged in the urine anyway.
Now, there are some documented minor interactions between amoxicillin and other diuretics, including:
- Furosemide
- Amiloride
Furosemide has been reported to cause small increases in amoxicillin concentrations while amiloride may decrease concentrations by inhibiting absorption in the intestines. In general, though, these are often reported as only minor interactions.
As mentioned, there have been no reported interactions between amoxicillin and hydrochlorothiazide (one of the components in Zestoretic).
Final Words
I hope you found this answer helpful!
If you'd like, you're more than welcome to write back and provide some specifics on where you read about the interaction and I would be happy to provide more context.
Thanks for reaching out!
References & sources
Glossary — Terms in This Answer
- Diuretic
- A medication that increases the production and elimination of urine from the body.
- Diuresis
- The increased production of urine by the kidneys.
- Excretion
- The process by which the body eliminates drugs or waste products, often through the kidneys in urine.
- Reabsorption
- The process by which substances filtered by the kidneys are taken back into the bloodstream.
- Amoxicillin
- A penicillin-type antibiotic used to treat bacterial infections like urinary tract infections.
- Hydrochlorothiazide
- A type of diuretic medication commonly used to treat high blood pressure.
- Peak concentrations
- The highest level of a drug present in the bloodstream after taking a dose.
- Absorption
- The process by which a drug passes from the digestive system into the bloodstream.
Dr. Brian Staiger, PharmD
Doctor of Pharmacy, board certified clinical pharmacist (BCPS), American Herbalist Guild, Medication Therapy Management certified
Brian Staiger, PharmD, BCPS, is a licensed pharmacist with more than 13 years of experience across retail pharmacy, clinical pharmacy, medication safety, pharmacy program development, and healthcare administration. He is the founder of HelloPharmacist.com, where he helps patients...
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