Classes
DEA Class; Rx
Common Brand Names; Nydrazid
- Antitubercular Agents
Description
Antimycobacterial agent; considered a first-line agent in the treatment of susceptible M. tuberculosis organisms. Appears to be more effective and less toxic than other antitubercular agents.
Indications
Other Indications & Uses
Newly infected patients
Household members and close associates of people recently diagnosed wtih TB
+ve TB skin test with +ve non-progressive chest x-ray
+ve TB skin test with underlying disease or immunosuppression
+ve TB skin test, <35 years old; >35 years old weigh use against risk of hepatitis
Contraindications
Prev INH hepatic injury or reaction; acute liver dz; pancreatitis
Hypersensitivity
Isoniazid is contraindicated in patients who develop severe hypersensitivity reactions, including drug-induced hepatitis; previous isoniazid-associated hepatic injury; severe adverse reactions to isoniazid such as drug fever, chills, arthritis; and acute liver disease of any etiology
Adverse Effects
- Mild incr LFTs (10-20%)
- Peripheral neuropathy (dose-related incidence, 10-20% incidence with 10 mg/kg/d)
- Loss of appetite
- Nausea
- Vomiting
- Stomach pain
- Weakness
- Dizziness
- Slurred speech
- Lethargy
- Progressive liver damage (increases with age; 2.3% in pts > 50 yo)
- Hyperreflexia
Warnings
Alcohol or illicit injectable drug use, predisposition to neuropathy, malnourished, severe renal impairment, chronic liver dz
Use w/ other anti-TB agents
Give pyridoxine (B6) concurrently for pregnant women, malnourished pts. or those with neuropathic diathesis
Alcohol use, renal or hepatic dysfunction will affect serum levels
Pregnancy and Lactation
Pregnancy Category: C
Lactation: distributed into milk but safe for nursing infants
Maximum Dosage
5 mg/kg/dose (Max: 300 mg/dose) PO/IV/IM once daily or 5 days/week or 15 mg/kg/dose (Max: 900 mg/dose) PO/IV/IM 3 days/week or twice weekly. 15 mg/kg/dose (Max: 900 mg) PO/IV/IM once daily or once weekly has been used off-label.
5 mg/kg/dose (Max: 300 mg/dose) PO/IV/IM once daily or 5 days/week or 15 mg/kg/dose (Max: 900 mg/dose) PO/IV/IM 3 days/week or twice weekly. 15 mg/kg/dose (Max: 900 mg) PO/IV/IM once daily or once weekly has been used off-label.
15 mg/kg/dose (Max: 300 mg/dose) PO/IV/IM once daily or 5 days/week or 40 mg/kg/dose (Max: 900 mg/dose) PO/IV/IM 3 days/week or twice weekly. 20 mg/kg/dose PO/IV/IM once daily or 15 mg/kg/dose (Max: 900 mg/dose) PO/IM once weekly have been used off-label.
12 years: 15 mg/kg/dose (Max: 300 mg/dose) PO/IV/IM once daily or 5 days/week or 40 mg/kg/dose (Max: 900 mg/dose) PO/IV/IM 3 days/week or twice weekly. 20 mg/kg/dose PO/IV/IM once daily or 15 mg/kg/dose (Max: 900 mg/dose) PO/IM once weekly have been used off-label.
2 to 11 years: 15 mg/kg/dose (Max: 300 mg/dose) PO/IV/IM once daily or 5 days/week or 40 mg/kg/dose (Max: 900 mg/dose) PO/IV/IM 3 days/week or twice weekly. 20 mg/kg/dose PO/IV/IM once daily and 25 mg/kg/dose (Max: 900 mg/dose) PO/IM once weekly have been used off-label.
1 year: 15 mg/kg/dose PO/IV/IM once daily or 5 days/week or 40 mg/kg/dose PO/IV/IM 3 days/week or twice weekly. 20 mg/kg/dose PO/IV/IM once daily has been used off-label.
15 mg/kg/dose PO/IV/IM once daily or 5 days/week or 40 mg/kg/dose PO/IV/IM 3 days/week or twice weekly. 20 mg/kg/dose PO/IV/IM once daily has been used off-label.
Safety and efficacy have not been established. 15 mg/kg/day PO/IV/IM has been used off-label.
Latent Tuberculosis Infection
Treatment of latent TB infection greatly reduces the risk that TB infection will progress to acitve disease
>30 kg: 300 mg PO qDay x9 months
3-month regimen
- Recommended for patients aged 12 years and older who are at high risk for developing TB disease including anyone who has had recent exposure to contagious TB, conversion from negative to positive on a test for TB infection, or a chest X-ray indicating prior TB disease
- Persons with HIV who are otherwise healthy and not taking antiretrovirals may also use this regimen
- 900 mg PO once weekly x3 months (administer with rifapentine 900 mg once weekly)
- Administered as DOT
- Not recommended for children <2 years, pregnant women or women planning to become pregnant, HIV-infected persons taking antiretrovirals, and patients whose TB infection is presumed to be the result of exposure to a person with TB disease that is resistant to 1 of the 2 drugs
- References: CDC MMWR 2011;60:1650-3 and NEJM 2011;365:2155-2166
Active Tuberculosis Disease
5 mg/kg PO/IM qDay, not to exceed 300 mg qDay
15 mg/kg PO/IM up; not to exceed 900 mg 1-3 times/week
Used in multi-drug regimen containing rifampin (or ribabutin or rifapentin), pyrazinamide, and ethambutol
Duration of treatment dependent on regimen consisting of an initial phase of treatment and a continutation phase of treatment
Note: Daily treatment has best results for HIV positive individuals
See Also Combos
With rifampin (Rifamate)
With rifampin and pyrizinamide (Rifater)
How supplied
Isoniazid
tablets
- 50mg
- 100mg
- 300mg
oral syrup
- 50mg/5mL
injectable solution
- 100mg/mL
