sil·​den·​a·​fil sil-ˈde-nə-ˌfil How to pronounce sildenafil (audio)
: a drug that is used in the form of its citrate C22H30N6O4S·C6H8O7 to treat erectile dysfunction in males, that by suppressing a phosphodiesterase enzyme also suppresses the enzyme's inhibitory effect on the hormone cyclic GMP, and that enables the cyclic GMP produced during sexual arousal to initiate the muscular and vascular changes which produce an erection

Note: Sildenafil is marketed under the trademarks Revatio and Viagra.

Examples of sildenafil in a Sentence

Recent Examples on the Web Also, researchers are currently testing a topical sildenafil in clinical trials to improve arousal and orgasm in people with clitorises, Streicher said. Kristen Rogers, CNN, 21 Mar. 2024 Visits cost $59, but doses of 50 mg sildenafil or 5 mg tadalafil go for as little as $0.50 per dose. Amber Smith, Discover Magazine, 19 Sep. 2023 Others say that Roman’s sildenafil works exactly as prescribed, with no tricks and awesome results. Amber Smith, Discover Magazine, 15 Sep. 2023 Is the information reporting the health benefits of sildenafil sound? Joe and Teresa Graedon, oregonlive, 19 June 2023 Participants received sildenafil citrate or a placebo drug — administered vaginally in the hopes of getting a stronger effect and bypassing any absorption issues — while menstruating. Calli McMurray, STAT, 17 Feb. 2023 These products are not FDA-approved and are not the same as prescription Viagra, which contains the active ingredient sildenafil. Amber Smith, Discover Magazine, 22 Jan. 2023 And the erectile dysfunction drug sildenafil citrate (Viagra), originally developed to reduce high blood pressure, also can benefit children with a rare form of lung disease. Karen Weintraub, USA TODAY, 18 Sep. 2022 Catuaba also appears to work better than sildenafil when given alone. Jon Goodwin, Discover Magazine, 29 Nov. 2022

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'sildenafil.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History


perhaps by alteration and recombination of letters from sulfonyl, phenyl, and pyrimidine

First Known Use

1995, in the meaning defined above

Time Traveler
The first known use of sildenafil was in 1995

Dictionary Entries Near sildenafil

Cite this Entry

“Sildenafil.” Dictionary, Merriam-Webster, Accessed 25 Jun. 2024.

Medical Definition


sil·​den·​a·​fil sil-ˈden-ə-ˌfil How to pronounce sildenafil (audio)
: a drug that is used in the form of its citrate C22H30N6O4S·C6H8O7 chiefly to treat erectile dysfunction in males and hypertension of the lungs

Note: Sildenafil inhibits a phosphodiesterase enzyme that degrades cyclic GMP. Higher levels of cyclic GMP in the body promote relaxation of smooth muscle, which allows for increased blood flow to the lungs to lower blood pressure and to the corpus cavernosum to produce an erection during sexual arousal. Sildenafil is marketed under the trademark Viagra to treat erectile dysfunction and under the trademark Revatio to treat pulmonary arterial hypertension.

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