Antitubercular Drugs: Classification, Mechanism, Uses & Side Effects (Easy Notes)

📌 Introduction  

Antitubercular drugs are used in the treatment of tuberculosis (TB), a serious infectious disease caused by Mycobacterium tuberculosis. TB mainly affects the lungs but can also involve other organs.

This is a very important topic for GPAT, DSSSB, and other pharmacy exams, with frequent questions asked every year.

🔍 What is Tuberculosis?  

Tuberculosis is a bacterial infection caused by Mycobacterium tuberculosis. It spreads through air when an infected person coughs or sneezes.

Types:

• Pulmonary TB → affects lungs  

• Extrapulmonary TB → affects other organs  

📝 Classification of Antitubercular Drugs  

Antitubercular drugs are classified into:

First-line drugs  

Examples: Isoniazid, Rifampicin, Pyrazinamide, Ethambutol  

Second-line drugs  

Examples: Streptomycin, Amikacin, Cycloserine  

🧬 Mechanism of Action  

• Isoniazid → inhibits mycolic acid synthesis  

• Rifampicin → inhibits RNA synthesis  

• Pyrazinamide → disrupts cell membrane  

• Ethambutol → inhibits cell wall synthesis  

🩺 Pharmacological Effects  

• Kill Mycobacterium tuberculosis  

• Prevent spread of infection  

• Reduce disease progression  

💊 Therapeutic Uses  

Used in:

• Pulmonary tuberculosis  

• Extrapulmonary tuberculosis  

• Latent TB infection  

🚨 Side Effects  

• Hepatotoxicity (Isoniazid, Rifampicin)  

• Peripheral neuropathy (Isoniazid)  

• Optic neuritis (Ethambutol)  

• Hyperuricemia (Pyrazinamide)  

📑 Important Exam Points  

• Isoniazid → most important drug  

• Rifampicin → enzyme inducer  

• Ethambutol → optic toxicity  

• TB treatment requires combination therapy  

🛑 Precautions  

• Monitor liver function  

• Avoid alcohol  

• Use combination therapy to prevent resistance  

🎯 Conclusion  

Antitubercular drugs play a vital role in controlling tuberculosis. Understanding their classification, mechanism, uses, and side effects is essential for exams and clinical practice.

👉 Practice MCQs in evening post

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