Isoniazid

A summary of the most common chemical descriptors (InChI Key and SMILES codes) for Isoniazid are summarized together with 3D and 2D structures and relevant physico-chemical properties.

What is the Isoniazid?

The molecule Isoniazid presents a molecular formula of C₆H₇N₃O and its IUPAC name is pyridine-4-carbohydrazide.

Isoniazid is an organic compound with the molecular formula C6H7N3O. It is an isonicotinic acid hydrazide, a first-line antituberculosis medication. It works by inhibiting the mycobacterial enzyme InhA, which is required for the synthesis of mycolic acids. Mycolic acids are a key component of the mycobacterial cell wall..

Isoniazid was first synthesized in 1952 by Hoffmann-La Roche. It is on the World Health Organization's List of Essential Medicines, the most effective and safe medicines needed in a health system. The wholesale cost in the developing world is about US$0.60–1.30 per month. In the United States, it costs more than US$100 per month..

Isoniazid is generally well-tolerated. The most common side effects are gastrointestinal upset, such as nausea and vomiting. More serious side effects include liver damage, which can lead to liver failure, and neuropathy..

Isoniazid is contraindicated in people with active tuberculosis, as it can worsen the disease. It is also contraindicated in people with severe liver impairment..

Isoniazid is an important part of treatment for latent tuberculosis infection (LTBI). It is recommended for people who are at high risk of developing active tuberculosis, such as people with HIV/AIDS, people who are immunocompromised, and people who have been in close contact with someone with active tuberculosis..

Isoniazid is also used to prevent active tuberculosis in people who have been exposed to the bacteria, such as healthcare workers..

Isoniazid is a prodrug that is converted to its active form, isonicotinic acid, by the enzyme catalase. Isonicotinic acid inhibits mycolic acid synthesis by inhibiting InhA. Mycolic acids are a key component of the mycobacterial cell wall..

Isoniazid is bactericidal against Mycobacterium tuberculosis. It is generally used in combination with other antituberculosis medications..

The recommended dose of isoniazid for latent tuberculosis infection is 900 mg once daily for 3 months. The recommended dose for active tuberculosis is 9 mg/kg/day (up to a maximum of 300 mg/day) for 2 months, followed by 4 mg/kg/day (up to a maximum of 300 mg/day) for 7 months..

Isoniazid is generally well-tolerated. The most common side effects are gastrointestinal upset, such as nausea and vomiting. More serious side effects include liver damage, which can lead to liver failure, and neuropathy..

Isoniazid is contraindicated in people with active tuberculosis, as it can worsen the disease. It is also contraindicated in people with severe liver impairment..

Isoniazid is an important part of treatment for latent tuberculosis infection (LTBI). It is recommended for people who are at high risk of developing active tuberculosis, such as people with HIV/AIDS, people who are immunocompromised, and people who have been in close contact with someone with active tuberculosis..

Isoniazid is also used to prevent active tuberculosis in people who have been exposed to the bacteria, such as healthcare workers..

3D structure

Cartesian coordinates

Geometry of Isoniazid in x, y and z coordinates (Å units) to copy/paste elsewhere. Generated with Open Babel software.

2D drawing

Molecule descriptors

Other names (synonyms)

IUPAC nomenclature provides a standardized method for naming chemical compounds. Although this system is widely used in chemistry, many chemical compounds have also other names commonly used in different contexts. These synonyms can come from a variety of sources and are used for a variety of purposes.

One common source of synonyms for chemical compounds is the common or trivial names, assigned on the basis of appearance, properties, or origin of the molecule.

Another source of synonyms are historical or obsolete names employed in the past, however replaced nowadays by more modern or standardized names.

In addition to common and historical names, chemical compounds may also have synonyms that are specific to a particular field or industry.

Reference codes for other databases

• CAS number (Chemical Abstracts Service Registry Number) is a unique identifier is assigned to every chemical compound indexed in the CAS database.
• Beilstein: The Beilstein database is a comprehensive source of information on organic chemistry, including information on chemical structures, properties, and reactions. The Beilstein database assigns unique identifiers which can be used to identify compounds in scientific literature and other sources.
• ChEBI (Chemical Entities of Biological Interest): ChEBI is a database of small chemical molecules that are of interest in the field of biology.
• PubChem CID (Compound Identifier): PubChem is a database of chemical compounds that is maintained by the National Institutes of Health (NIH).
• RTECS number (Registry of Toxic Effects of Chemical Substances): The RTECS is a database of information on the toxic effects of chemicals, including information on their structures and properties.
• ChEMBL (Compound Bioactivity Data): ChEMBL is a database of bioactivity data for small molecules, including information on their properties and structures.
• CompTox Dashboard (Environmental Protection Agency): The CompTox Dashboard is a database of information on the toxicology and environmental effects of chemicals.

Physico-Chemical properties

LogP and topological polar surface area (TPSA) values were estimated using Open Babel software.

The n-octanol/water partition coeficient (K_ow) data is applied in toxicology and drug research. K_ow values are used, to guess the environmental fate of persistent organic pollutants. High partition coefficients values, tend to accumulate in the fatty tissue of organisms. Molecules with a log(K_ow) (or LogP) greater than 5 are considered to bioaccumulate.

TPSA values are the sum of the surface area over all polar atoms or molecules, mainly oxygen and nitrogen, also including hydrogen atoms.

In medicinal chemistry, TPSA is used to assess the ability of a drug to permeabilise cells.

For molecules to penetrate the blood-brain barrier (and act on receptors in the central nervous system), TPSA values below 90 Ų are required. Thus, molecules with a polar surface area greater than 140 Ų tend to be poorly permeable to cell membranes.