Isoniazid is an antibiotic that fights bacteria.
Isoniazid is used to treat and to prevent tuberculosis (TB). You may need to take other TB medicines in combination with isoniazid.
When treating active TB, isoniazid must be used with other TB medicines. Tuberculosis can become resistant to treatment if isoniazid is used alone. Take all your medicines as prescribed by your doctor.
Isoniazid may also be used for purposes not listed in this medication guide.
