Last reviewed 01/2018

The prime indication for its use is in tuberculosis.

Caution should be exercised when using it in the presence of:

  • epilepsy
  • history of psychosis
  • alcoholism
  • impaired liver and kidney function
  • breast feeding

Contra-indications include:

  • drug-induced liver disease
  • porphyria

Side-effects of isoniazid include:

  • peripheral neuropathy with high doses or in patients with pyridoxine deficiency
  • convulsions
  • psychotic episodes
  • nausea and vomiting
  • hypersensitivity reactions including rashes
  • agranulocytosis
  • hepatitis
  • SLE like syndrome

Routes of administration:

  • oral:
    • tablets
    • elixir
  • i.m. injection
  • i.v. injection

The summary of product characteristics should be consulted before prescribing this drug.