11. Anti- Mycobacterial Drugs: Second Line Drugs (Part-2): Pharmacology Video Lectures

𝐒𝐮𝐛𝐬𝐜𝐫𝐢𝐛𝐞 𝗙𝐨𝐫 𝗠𝐨𝐫𝐞 𝗜𝐧𝐟𝐨𝐫𝐦𝐚𝐭𝐢𝐨𝐧 𝐨𝐧 𝗛𝐞𝐚𝐥𝐭𝐡 👩‍⚕‍ 𝐚𝐧𝐝 𝗠𝐞𝐝𝐢𝐜𝐢𝐧𝐞💉🩺💊 📌𝗜𝗻𝘀𝘁𝗮𝗴𝗿𝗮𝗺 :   / clinical.learning   11. Anti- Mycobacterial Drugs: Second Line Drugs (Part-2): Pharmacology Video Lectures ---------------------------------------------------------------------------------------------------------------------- Second-line anti-mycobacterial drugs are used in cases of multidrug-resistant tuberculosis (MDR-TB) and extensively drug-resistant tuberculosis (XDR-TB) when first-line drugs (Rifampin, Isoniazid, Pyrazinamide, Ethambutol) fail or cannot be tolerated 💊🦠. These drugs are less effective, have higher toxicity, and require longer treatment durations, making MDR-TB treatment more challenging 🏥🚨. The second-line drugs include fluoroquinolones, aminoglycosides, polypeptides, thioamides, and newer agents like Bedaquiline and Delamanid, which target different Mycobacterium tuberculosis pathways 🔬🛡️. 🔹 Fluoroquinolones (Levofloxacin, Moxifloxacin, Gatifloxacin): These inhibit bacterial DNA gyrase (topoisomerase II), preventing DNA replication, making them bactericidal 📜⚠️. They are the most effective oral second-line drugs but have risks like QT prolongation, tendon rupture, and neurotoxicity 🚨💉. 🔹 Aminoglycosides (Amikacin, Kanamycin, Capreomycin, Streptomycin): These bind to the 30S ribosomal subunit, inhibiting protein synthesis and are bactericidal 🦠🔬. However, their major toxicities include ototoxicity (hearing loss, vestibular damage) and nephrotoxicity (acute kidney injury), requiring regular monitoring of renal function and hearing ⚠️🩺. 🔹 Thioamides (Ethionamide, Prothionamide): These drugs inhibit mycolic acid synthesis, similar to Isoniazid, and are used in MDR-TB regimens 🧬💊. However, they cause severe gastrointestinal side effects (nausea, vomiting, metallic taste) and hepatotoxicity, making them difficult to tolerate 😖⚠️. 🔹 Polypeptides (Capreomycin, Viomycin, Enviomycin, Ristocetin): These drugs inhibit protein synthesis and are used as injectable second-line agents, particularly for MDR-TB 💉💥. Their toxicities include nephrotoxicity and ototoxicity, similar to aminoglycosides 🚨🦻. 🔹 Newer Drugs (Bedaquiline, Delamanid, Pretomanid): Bedaquiline is a diarylquinoline that inhibits mycobacterial ATP synthase, making it the first FDA-approved drug for MDR-TB in 40 years 🏆🦠. However, it has QT prolongation risk and hepatotoxicity, requiring cardiac and liver monitoring ⚠️📉. Delamanid disrupts mycolic acid synthesis, improving MDR-TB cure rates, but can also cause QT prolongation and requires close ECG monitoring 🩸📊. Pretomanid, used in combination with Bedaquiline and Linezolid (BPaL regimen), is a promising therapy for highly drug-resistant TB cases 🦠💡. 🔹 Challenges in Second-Line TB Therapy: Prolonged treatment duration (18–24 months), high costs, severe side effects, and poor patient compliance make MDR-TB treatment difficult 🔄🏥. Drug resistance (e.g., fluoroquinolone-resistant TB, XDR-TB) further complicates therapy, requiring individualized regimens 🛑💊. Strict DOTS (Directly Observed Therapy Short-Course) programs and global TB control efforts are necessary to improve adherence and prevent further resistance 🌍💉. 🔹 Contraindications & Monitoring: Patients on second-line TB drugs require regular hearing tests (for aminoglycosides), ECGs (for fluoroquinolones & Bedaquiline), liver function tests (for thioamides & Bedaquiline), and renal function monitoring 🏥🩺. 🔹 Conclusion: Second-line anti-mycobacterial drugs are lifesaving for MDR-TB and XDR-TB but require rigorous monitoring, combination therapy, and patient adherence to ensure successful treatment outcomes while minimizing drug resistance and toxicities 🌍💊. #SecondLineTBDrugs #MDRTB #XDRTB #Fluoroquinolones #Aminoglycosides #Bedaquiline #Delamanid #Ethionamide #TBResistance #MycobacteriumTuberculosis #SaveLives #TBPrevention #Pharmacology #Microbiology #USMLE #NEETPG #GlobalHealth #DOTS 💊🦠🔬