TREATMENT OF LATENT TUBERCULOSIS WITH ISONIAZID

Daily treatment with isoniazid for 12 months was shown to reduce the risk for active tuberculosis by more than 90%. A shorter 6-month regimen can also provide a reduced risk (approximately 70%) against the development of active infection. A 9-month regimen provides even greater protection than the 6-month regimen and is considered the optimal length of therapy. A 6-month regimen is an acceptable, but less effective, regimen for adults. However, a 6-month regimen should not be used in HIV patients, those younger than 18 years of age, and those with fibrotic lesions suggestive of old tuberculosis on chest radiograph.

The dose of isoniazid is 300 mg daily in adults and 10 to 15 mg/kg per day (not to exceed 300 mg daily) in children. Twice-weekly dosing is also an acceptable alternative and may be useful when directly observed therapy is undertaken. The twice-weekly dose is 900 mg (20 to 40 mg/kg in children). The length of treatment is for 9 or 6 months as outlined above for the once – daily therapy.

Pregnant women who are at high risk of developing active disease (for example, those who are HIV positive) should be offered isoniazid even in the first trimester. Isoniazid is not teratogenic, even if taken in the first trimester. For women whose risk of active disease is lower, waiting until after delivery to start isoniazid treatment is also acceptable.

Baseline measurement of liver-associated enzymes and bilirubin is not uniformly recommended but should be obtained in patients with known or suspected liver disease (due to hepatitis В or C, chronic alcohol abuse, or other chronic liver disease), HIV infection, and in pregnant or postpartum women. Active hepatitis and end-stage liver disease are considered contraindications to therapy with isoniazid for latent tuberculosis infection.

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TREATMENT OF LATENT TUBERCULOSIS WITH ISONIAZIDDaily treatment with isoniazid for 12 months was shown to reduce the risk for active tuberculosis by more than 90%. A shorter 6-month regimen can also provide a reduced risk (approximately 70%) against the development of active infection. A 9-month regimen provides even greater protection than the 6-month regimen and is considered the optimal length of therapy. A 6-month regimen is an acceptable, but less effective, regimen for adults. However, a 6-month regimen should not be used in HIV patients, those younger than 18 years of age, and those with fibrotic lesions suggestive of old tuberculosis on chest radiograph.The dose of isoniazid is 300 mg daily in adults and 10 to 15 mg/kg per day (not to exceed 300 mg daily) in children. Twice-weekly dosing is also an acceptable alternative and may be useful when directly observed therapy is undertaken. The twice-weekly dose is 900 mg (20 to 40 mg/kg in children). The length of treatment is for 9 or 6 months as outlined above for the once – daily therapy.Pregnant women who are at high risk of developing active disease (for example, those who are HIV positive) should be offered isoniazid even in the first trimester. Isoniazid is not teratogenic, even if taken in the first trimester. For women whose risk of active disease is lower, waiting until after delivery to start isoniazid treatment is also acceptable.Baseline measurement of liver-associated enzymes and bilirubin is not uniformly recommended but should be obtained in patients with known or suspected liver disease (due to hepatitis В or C, chronic alcohol abuse, or other chronic liver disease), HIV infection, and in pregnant or postpartum women. Active hepatitis and end-stage liver disease are considered contraindications to therapy with isoniazid for latent tuberculosis infection.*56/348/5*