About isoniazid
Antituberculosis antibiotic
Used for
- Treats tuberculosis, usually with other medicines.
- Prevents tuberculosis in people with latent infection.
Usual adult dose
Active tuberculosis: usually 5 mg/kg once daily, maximum 300 mg. Latent infection regimens vary.
Usual dose in children
Active tuberculosis: usually 10–15 mg/kg once daily, maximum 300 mg. Latent infection regimens vary.
Common side effects
- Nausea, stomach discomfort, or loss of appetite
- Liver inflammation or liver failure
- Numbness or tingling in hands and feet
- Rash or fever
Important warnings
- Can cause serious liver damage; risk increases with alcohol use or liver disease.
- Report yellow skin, dark urine, severe fatigue, or persistent nausea promptly.
- Pyridoxine (vitamin B6) may be prescribed to reduce nerve problems.
- Injection is generally reserved for situations where oral treatment is unsuitable.
Pregnancy
Used when needed to treat or prevent tuberculosis; treatment requires clinical monitoring.
Breastfeeding
Generally compatible; small amounts enter milk. Infant exposure may be insufficient for treatment.
Interactions
- Rifampin and other liver-damaging medicines can increase liver injury risk.
- Can increase phenytoin or carbamazepine levels.
- Can interact with warfarin, increasing bleeding risk.
- Alcohol increases the risk of liver damage.
AI-generated from general medical knowledge, not from this product's official leaflet. It may be incomplete or out of date. Not medical advice — ask a pharmacist or doctor before making any decision.