Introduction to Isoniazid
Isoniazid is a cornerstone drug used in the treatment of
tuberculosis (TB), a serious infectious disease primarily affecting the lungs. Since its discovery in the 1950s, it has played a crucial role in TB control efforts worldwide. Isoniazid is highly effective against Mycobacterium tuberculosis, the bacterium responsible for TB, and is often used in combination with other drugs to prevent resistance.
Mechanism of Action
Isoniazid is a
bactericidal agent that works by inhibiting the synthesis of mycolic acids, essential components of the mycobacterial cell wall. By disrupting the formation of these acids, isoniazid effectively kills the bacteria, preventing them from multiplying and spreading within the host.
Indications
Isoniazid is primarily indicated for the treatment and prevention of tuberculosis. It is a key component of multi-drug regimens, such as the
DOTS strategy recommended by the World Health Organization. Additionally, it is used in
latent tuberculosis infection (LTBI) management to prevent the progression to active disease, especially in high-risk populations.
Dosage and Administration
The typical dosage of isoniazid for adults is 5 mg/kg daily, not exceeding 300 mg per day, when used for active TB. For LTBI, the usual dose is 300 mg once daily for 6 to 9 months. It's crucial to adhere to prescribed regimens to prevent the development of drug-resistant TB strains. Side Effects and Monitoring
Common side effects of isoniazid include peripheral neuropathy, which can be mitigated with
pyridoxine (Vitamin B6) supplementation, liver enzyme elevation, and hypersensitivity reactions. Regular monitoring of liver function tests is recommended due to the risk of
drug-induced hepatitis, particularly in patients with preexisting liver conditions or those who consume alcohol regularly.
Drug Interactions
Isoniazid interacts with several medications, including
phenytoin and carbamazepine, by inhibiting their metabolism and increasing their plasma levels. It is essential to adjust doses accordingly and monitor patients closely for signs of toxicity. Additionally, isoniazid can potentiate the effects of certain benzodiazepines and warfarin, necessitating careful management.
Resistance Concerns
The emergence of isoniazid-resistant TB strains poses significant challenges to global TB control efforts. Resistance can result from inadequate treatment regimens, patient non-adherence, or inappropriate prescribing practices. To combat resistance, healthcare providers must ensure proper drug combinations and adherence to treatment guidelines. Role in Public Health
Isoniazid remains a critical component of TB control programs worldwide. Its use in
preventive therapy for individuals with latent TB infection helps reduce the incidence of active TB, thereby decreasing transmission rates. Public health initiatives often focus on increasing awareness, improving diagnostic methods, and ensuring access to effective treatment regimens to combat TB.
Conclusion
Isoniazid continues to be an indispensable drug in the fight against tuberculosis. Its efficacy in treating and preventing TB, coupled with its role in public health strategies, underscores its importance in controlling this infectious disease. Ongoing research and vigilance are necessary to address challenges such as drug resistance and to improve TB management globally.
