fenfluramine
noun
fen·flur·amine
ˌfen-ˈflu̇r-ə-ˌmēn 
: an anorectic amphetamine derivative C12H16F3N with little stimulant effect on the central nervous system formerly used in the form of its hydrochloride to treat obesity but no longer used due to its association with heart valve disease see fen-phen sense 1
Examples of fenfluramine in a Sentence
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This week in 1997, two popular diet drugs — fenfluramine and dexfenfluramine — were withdrawn from the market by their manufacturers after the U.S. Food and Drug Administration established a possible link between heart valve damage and their use.
—
Scott Lafee, San Diego Union-Tribune, 16 Sep. 2025
Subsequent studies estimated that seven out of 10,000 people who took fenfluramine or fen-phen for less than four months developed valve disease, while 35 in 10,000 people who took fenfluramine or fen-phen for more than four months developed valve disease.
—Dr. Keith Roach, oregonlive, 28 Aug. 2023
One of the drugs in the combination known as fen-phen (a combination of fenfluramine and phentermine) was famously withdrawn in 1997 for damaging patients' heart valves.
—Karen Weintraub, USA TODAY, 20 Feb. 2023
In 1997, weight loss drug fenfluramine/phentermine (fen-phen) was pulled off the market after it was found to cause heart problems.
—Alexandra Ossola, Quartz, 19 June 2022
Belviq is chemically similar to fenfluramine, which was removed from the market after the fen-phen heart valve problems.
—John Fauber, Milwaukee Journal Sentinel, 22 Aug. 2021
Sure enough, fenfluramine activated the brain's receptors with a flood of serotonin, just like MDMA.
—Jennifer Walter, Discover Magazine, 11 Dec. 2019
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Scott Lafee, San Diego Union-Tribune, 16 Sep. 2025
Subsequent studies estimated that seven out of 10,000 people who took fenfluramine or fen-phen for less than four months developed valve disease, while 35 in 10,000 people who took fenfluramine or fen-phen for more than four months developed valve disease.
—Dr. Keith Roach, oregonlive, 28 Aug. 2023
One of the drugs in the combination known as fen-phen (a combination of fenfluramine and phentermine) was famously withdrawn in 1997 for damaging patients' heart valves.
—Karen Weintraub, USA TODAY, 20 Feb. 2023
In 1997, weight loss drug fenfluramine/phentermine (fen-phen) was pulled off the market after it was found to cause heart problems.
—Alexandra Ossola, Quartz, 19 June 2022
Belviq is chemically similar to fenfluramine, which was removed from the market after the fen-phen heart valve problems.
—John Fauber, Milwaukee Journal Sentinel, 22 Aug. 2021
Sure enough, fenfluramine activated the brain's receptors with a flood of serotonin, just like MDMA.
—Jennifer Walter, Discover Magazine, 11 Dec. 2019
Cite this Entry
“Fenfluramine.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/fenfluramine. Accessed 15 Jan. 2026.
Copy CitationMedical Definition
fenfluramine
noun
fen·flur·amine
ˌfen-ˈflu̇r-ə-ˌmēn
: an anorectic amphetamine derivative C12H16F3N with little stimulant effect on the central nervous system formerly used in the form of its hydrochloride to treat obesity but no longer used due to its association with heart valve disease see dexfenfluramine, fen-phen sense 1
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