Isoniazid preventative therapy is widely used for latent tuberculosis infection. Isoniazid is highly effective but has many adverse effects, including neuropsychiatric. We describe the case of an 80-year-old woman with mania. She had received isoniazid preventative therapy during steroid treatment for rheumatoid arthritis and organising pneumonia for the previous 5 months. Her mania resolved after discontinuation of isoniazid. Adverse effects of isoniazid should be considered even if a long time has elapsed since the start of administration. Physicians other than infectious disease and respiratory specialists also must be aware of the adverse effects of isoniazid preventative therapy.
Keywords: TB and other respiratory infections; unwanted effects/adverse reactions.
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