iso·​ni·​a·​zid | \ ˌī-sə-ˈnī-ə-zəd How to pronounce isoniazid (audio) \

Definition of isoniazid

: a crystalline compound C6H7N3O used in treating tuberculosis

Examples of isoniazid in a Sentence

Recent Examples on the Web Apolisi, together with a physician colleague, ensures that children in close contact with her TB patients take the daily preventive medication isoniazid for at least six months, as recommended by the WHO. Sofia Moutinho, Scientific American, 14 May 2022 Extensively drug-resistant TB (XDR-TB) is a form of MDR-TB that is resistant to isoniazid and rifampin, in addition to fluoroquinolones and injectable second-line drugs. Cnn Editorial Research, CNN, 6 June 2021 In the past decade, scientists have come up with two shorter courses: a drug called rifampin taken every day for four months; or a combination of isoniazid and rifapentine, taken once weekly for three months. Apoorva Mandavilli, New York Times, 23 Sep. 2019 But several studies have shown that isoniazid combined with rifapentine prevents TB if the pills are taken once a week for 12 weeks. Jon Cohen, Science | AAAS, 31 Oct. 2019 The World Health Organization has estimated that in 2016, some 600,000 cases of tuberculosis were resistant to at least two of the front-line drugs used to treat tuberculosis, rifampicin and isoniazid. Melissa Healy,, 25 Apr. 2018 Doctors have been prescribing two TB drugs, rifampicin and isoniazid, for almost half of a century. Emily Baumgaertner, New York Times, 6 Apr. 2018 Patients received standard drug doses to treat TB, but concentrations in the blood were found to be jarringly low: 84 percent of the participants had substandard levels of isoniazid, and 78 percent fell below targets for rifampicin. Emily Baumgaertner, New York Times, 6 Apr. 2018 See More

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

First Known Use of isoniazid

1952, in the meaning defined above

History and Etymology for isoniazid

is- + nicotinic acid + hydrazide

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The first known use of isoniazid was in 1952

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Cite this Entry

“Isoniazid.” Dictionary, Merriam-Webster, Accessed 6 Oct. 2022.

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More Definitions for isoniazid


iso·​ni·​a·​zid | \ ˌī-sə-ˈnī-ə-zəd How to pronounce isoniazid (audio) \

Medical Definition of isoniazid

: a crystalline compound C6H7N3O used in treating tuberculosis

called also isonicotinic acid hydrazide

More from Merriam-Webster on isoniazid Encyclopedia article about isoniazid


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