Isoniazid is an antibiotic primarily used to treat and prevent tuberculosis (TB), a serious infectious disease that affects the lungs. It works by inhibiting the growth of the bacteria that cause TB, making it an essential part of TB treatment regimens. Isoniazid is often prescribed in combination with other medications to enhance its effectiveness and reduce the risk of drug resistance. This medication is usually taken orally, either as a tablet or liquid, and is typically prescribed for several months. Common side effects may include liver toxicity, peripheral neuropathy, and gastrointestinal issues. Regular monitoring by a healthcare provider is important to ensure safety and effectiveness during treatment.