Testing an antibiotic to lower hard-to-control high blood pressure

Plain-English translation of NCT06246396 on ClinicalTrials.gov ↗ · Source last updated March 2026 · Translation generated June 2026 · How we translate trials

Phase 4 — The treatment has already been approved. Researchers are tracking how it works in a large number of people over time.

What is this trial?

This trial is testing whether minocycline, an antibiotic, might help lower blood pressure in people whose high blood pressure hasn't responded well to three or more standard blood pressure medications. Researchers believe this medication may work by changing the balance of bacteria in your gut and reducing inflammation in your body. You'll either receive the medication or a placebo (a pill with no active ingredient) over 3 months while doctors monitor your blood pressure and collect blood, urine, and stool samples.

Some people's high blood pressure simply doesn't respond well to standard medications, which can be serious and lead to heart problems. This trial is exploring whether this medication might work through a new pathway — by affecting gut bacteria and immune responses — to help control blood pressure in people who haven't benefited from conventional treatments.

Do you qualify?

You likely qualify if…

you are 18 years of age or older
you have been diagnosed with high blood pressure that remains uncontrolled despite taking three or more blood pressure medications steadily for at least 2 weeks
your 24-hour ambulatory blood pressure reading (a test that measures pressure continuously over a day) shows a systolic pressure of 125 mm Hg or higher, or diastolic pressure of 80 mm Hg or higher
you are willing and able to attend three study visits over 3 months and undergo blood tests, urine tests, stool samples, and blood pressure monitoring

You likely don't qualify if…

you are allergic or sensitive to minocycline or similar antibiotics (tetracyclines)
you have been taking oral antibiotics recently (within the past 3 months) or expect to take them during the study
you have kidney disease with an estimated glomerular filtration rate below 45 mL/min/1.73m²
you have experienced a hypertensive crisis requiring hospitalization, severe drop in blood pressure upon standing, or major heart or stroke events in the past 6 months to 1 year
you are pregnant, planning to become pregnant, or have a history of substance abuse or severe conditions like cancer or HIV/AIDS

What participation looks like

You will visit the study site three times over 3 months: at the start, when you begin taking the medication or placebo, and at the final follow-up. At each visit, you'll have your blood pressure measured, answer health questionnaires, and provide blood, urine, and stool samples so researchers can check how the medication is affecting your body's bacteria, immune system, and blood pressure. A smaller group of 34 participants will also undergo special brain imaging scans (at a partner site in Atlanta) to help researchers understand how this medication works in the brain.

AI-generated summary from trial data · Jun 8, 2026 · Not medical advice

Trial locations(1 site)

United States

UF Clinical Research Center (UF CRC) - CTSI, Gainesville, Florida