Isoniazid is available in both 100mg and 300mg tablets and is consumed orally. It is an antibacterial treatment with the chemical name of isonicotinyl hydrazine with a formula of C6H7N30. It is both odorless and colorless and recommended for the treatment of all forms of tuberculosis. Active tuberculosis, however, requires multiple doses of several medication. In addition for the treatment of both active and inactive tuberculosis, Isoniazid is an effective tuberculosis preventative therapy for those with HIV, those who are in close contact with persons afflicted with infectious tuberculosis, people with abnormal chest radiographs, and those with a medical condition that causes an increase in the risk of tuberculosis.

It is important to note that several forms of hepatitis are associated with the usage of isoniazid and has been reported as a development occurring months after treatment. This risk is related in age. Those who are younger in age have a much lower risk of developing hepatitis but the risk increases significantly for those over the age of 35 with an occurrence of 12 per 1000 people. The risk doubles for those over 50 with an occurrence of 23 per 1000 people surveyed. This risk is also increased with consumption of alcohol therefore, those taking isoniazid should not consume alcohol while undergoing treatment. Patients using isoniazid should be monitored by a doctor and treatment should stop at the first sign of hypersensitivity. Those over the age of 35 experience greater risk associated with the drug and as a result should weigh the benefits with the risk.