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.

Example Sentences

Recent Examples on the Web 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 The most common drugs, such as sildenafil (Viagra), work mostly on blood vessels but also have effects on raising both testosterone levels and estrogen levels in men. Dr. Keith Roach, oregonlive, 15 Apr. 2022 Doctors have indeed been using sildenafil in some cases to treat PAH. Bruce Y. Lee, Forbes, 18 Apr. 2022 The interaction between nitrates and sildenafil can lower blood pressure to dangerous levels, the FDA warns. Chris Smith, BGR, 7 Mar. 2022 The capsules were tested and found to contain sildenafil, the active ingredient in Viagra and other prescription medications used to treat erectile dysfunction in men. Elainie Barraza,, 1 Feb. 2022 See More

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'sildenafil.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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 23 Mar. 2023.

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.

Last Updated: - Updated example sentences
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