Drugs for TB + updates on TB guidelines Flashcards
What comprises the complex lipid in M. tuberculosis
Mycolic acid, cord factor, Wax D
Other name of cord factor
Serpentine factor
What type of hypersensitivity is shown in mantoux test
Type IV/delayed type
When is a cutoff of 5mm in mantoux test considered positive
immunocompromised, close contact with TB positive, with clinical signs of TB, chest x-ray shows fibrotic changes
When is a cutoff of 10mm in mantoux test used
persons with injection drug use, people in high-risk places, children <4
When is a person classified as tb new case
never been treated for TB / taken anti-TB drugs for < 1 month
TB retreatment - relapse
previously treated, declared cured/treatment completed, now diagnosed with recurrent TB
Diagnostic algorithm for TB (prev guidelines)
with signs -> smear -> CXR if smear neg -> gene Xpert if CXR pos to show resistance to rif
Mechanism of resistance of isoniazid
Mutations in KatG gene
MOA of isoniazid
Inhibition of mycolic acid synthesis
MOA of rifampicin
Interferes withRNA polymerase
Mechanism of resistance of rifampicin
Mutation in rpoB gene
What is the active form of pyrazinamide that decreases the pH of the M. tuberculosis cell
Pyrazinoic acid
MOA of ethambutol
Inhibits arabinosyl transferase
MOA of streptomycin
Inhibits translation during protein synthesis
What does sterilizing activity of anti-TB drugs mean
Drug can kill all organisms - even those not actively multiplying
What are the only anti-TB drugs with sterilizing activity
Rifampicin, Pyrazinamide
What anti-TB drug kills intracellular bacilli only
Pyrazinamide
What is the only bacteriostatic anti-TB drug
Ethambutol
What anti-TB drug kills extracellular bacilli only
Streptomycin
How to prevent isoniazid-induced peripheral neuropathy
Vitamin B6 (pyridoxine)
What drug causes red orange urine discoloration
Rifampicin
ADR of pyrazinamide
Hyperuricemia
ADRs of streptomycin
nephrotoxicity, ototoxicity, vestibulotoxicity
