High Yield Topic Series for NEET PG Exam Preparation
MDR TB Definitions and Two new Anti-TB Drugs :
Some very important high yield points regarding MDR-TB are
- As per WHO, The patients whose clinical isolates are resistant to both Isoniazid and rifampicin are defined as MDR-TB
- Pre-XDR-TB ( Pre –extensively Drug resistant TB)- Resistant to Fluoroquinolones or at least one of the three injectable second line drugs in addition to MDR-TB is defined as Pre-XDR-TB.
- XDR- TB ( Extensively Drug Resistance-TB): Resistant to both Fluoroquinolones and at least one of the three injectable second line drugs in addition to MDR-TB is defined as XDR-TB.
Newer Anti- TB drugs:
A.Bedaquiline: It is a new drug approved for the treatment of MDR-TB.
Mechanism of action- Blocks ATP synthase enzyme inside Mycobacterium . Bedaquiline, diarylquinoline, binds to subunit c of mycobacterial ATP synthase (an enzyme essential for the energy production in M. tuberculosis) and inhibits its activity. It is highly selective for mycobacterial ATP synthase enzyme compared to homologous eukaryotic enzyme (Selectivity Index >20 000). Recommended dose is 400 mg once daily for 2 weeks followed by 200 mg thrice weekly for 22 weeks. After 24 weeks of Bedaquiline therapy, MDR-TB regimen should be continued as per national TB treatment guidelines.
Side Effects :
1.GIT side effects- nausea, vomiting, Hepatitis
- Headache, Arthralgia,Skin rash
- QTc prolongation
B: Delamanid: Delamanid is a dihydro-nitroimidazooxazole derivative.
Indicated for treatment of MDR-TB
Mechanism: It acts by inhibiting the synthesis of mycobacterial cell wall components, methoxy mycolic acid and ketomycolic acid.
Delamanid is a pro-drug which gets activated by the enzyme deazaflavin dependent nitroreductase (Rv3547). A reactive intermediate metabolite, formed between delamanid and desnitro-imidazooxazole derivative, is considered to play a vital role in the inhibition of mycolic acid production. ( source- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4156838/)
Dosage: 100 mg Twice weekly for 24 weeks
Side Effects of Delamanid:
- GIT – Nausea, vomiting, Pain abdomen
- Peripheral neuropathy
- QTc Prolongation
So we advise all students to prepare this topic of MDR-TB definitions and two newer drugs Bedaquiline and Delamanid for NEET PG Exam Preparation.
Stay tuned for more topics and book our website for regular High yield NEET PG Exam Topics .
Our website is www.pgmedexam.com
If you have any query, you can send email at
TEAM NEET PG Quiz
Other High Yield NEET PG Topics are given below: