Definition of isoniazid in English:



mass nounMedicine
  • A synthetic compound used as a bacteriostatic drug, chiefly to treat tuberculosis.

    A derivative of nicotinic acid and hydrazine; chemical formula: C₅H₅NCONHNH₂

    • ‘Most patients with latent tuberculosis are treated with isoniazid administered daily for nine months.’
    • ‘Further clinical studies are needed to determine whether the moxifloxacin adds to the bactericidal activity of isoniazid or rifampin.’
    • ‘Drug susceptibility patterns to isoniazid and rifampicin by the conventional method showed complete association with E-test results.’
    • ‘First, most patients treated with isoniazid were less than 35 years old.’
    • ‘Another form of hepatitis is chemical hepatitis caused by alcohol, some anesthetics, nitrofurantoin, isoniazid, and other drugs.’
    • ‘Even the addition of a bactericidal drug streptomycin to isoniazid only resulted in a marginal increase to 49 per cent.’


1950s: from iso- ‘equal’ + ni(cotinic) + ( hydr)azine + -ide.