Quiz: Remember the definition of mal de mer?


[ahy-suh-nahy-uh-zid] /ˌaɪ səˈnaɪ ə zɪd/
noun, Pharmacology
a white, crystalline, water-soluble solid, C 6 H 7 N 3 O, used in the treatment of tuberculosis.
1950-55; short for isonicotinic acid hydrazide Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2015.
Cite This Source
British Dictionary definitions for isoniazid


a soluble colourless crystalline compound used to treat tuberculosis. Formula: C6H7N3O
Word Origin
C20 isoni(cotinic acid hydr)azid(e)
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
Cite This Source
isoniazid in Medicine

isoniazid i·so·ni·a·zid (ī'sə-nī'ə-zĭd)
An antibacterial compound used in the treatment of tuberculosis.

The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
Cite This Source
Encyclopedia Article for isoniazid

drug used in the treatment and prevention of tuberculosis. Isoniazid commonly is used in combination with other drugs, such as rifampin, ethambutol, pyrazinamide, or streptomycin; these drugs are used with isoniazid in order to prevent, or at least delay, the development of isoniazid-resistant strains of tuberculin bacilli. Treatment usually is continued for many months. The most important drug in the therapy of tuberculosis, isoniazid was introduced into medicine in 1952; it usually is administered orally, but it can be given by injection. Side effects may include hepatitis (especially in older patients), peripheral neuropathy, dizziness, and headache.

Learn more about isoniazid with a free trial on
Encyclopedia Britannica, 2008. Encyclopedia Britannica Online.
Cite This Source

Word of the Day

Difficulty index for isoniazid

Few English speakers likely know this word

Word Value for isoniazid

Scrabble Words With Friends