antimycobacterial drugs Flashcards
Rod-shaped, aerobic bacteria that are intrinsically resistant to most antibiotics
Mycobacteria
Used to stain mycobacteria
Acid-fast staining
Gives out the red color when stained, indicative of presence of high lipids
Carbol-fuschin
Causative agent of PTB and EPTB
M. tuberculosis
Causative agent Leprosy
M. leprae
Used for BCG vaccination
Prevents severe forms of tuberculosis
M. bovis
Causative agent of disseminated infection, pulmonary infections
Common in immunocompromised states/HIV
Mycobacterium avium complex
2nd line drug used in combination for life-threatening TB
Meningitis
Miliary TB
Other EPTB
Streptomycin
For TB caused by streptomycin-resistant or MDR-TB
Amikacin
Fluoroquinolones active against strains of MTB resistant to first-line agents
Ciprofloxacin and ofloxacin
2nd line drug that is a congener of INH, causes severe GI irritation and neurologic toxicity
Ethionamide
Duration of intensive phase
2 months
Duration of continuation or maintenance phase
4 months and above
Why are bone, spine, cartilage TB treated for 1 yr
Harder to penetrate
Poor blood flow
Treatment plan for TB 1st timers
2HRZE, 4HR
Treatment plan for TB 2nd timers
HRZE might not be enough
Modify plan and add 2nd line drugs
MTB strains that are resistant to isoniazid and rifampicin
MDR-TB
Extremely drug resistant strains
XDR-TB
What does DOTS stand for
Directly Observed Treatment Strategy
How many sputum specimens are taken for testing? What is the time interval?
2 specimens, 60 mins interval
Molecular technique that detects the presence of mycobacteria and Rifampicin resistance
Gene expert
Inhibits enzymes required for mycolic acid synthesis
Isoniazid
Inhibits DNA-dependent RNA polymerase
Rifampicin
Inhibits arabinosyltransferase enzyme needed for cell wall synthesis
Ethambutol
Bactericidal Agents
Isoniazid, Rifampicin
TB Bacteriostatic Agents
Ethambutol, Pyrazinamide
Catalase peroxidase bioactivation of INH
Inactivates isoniazid
katG gene
Enzyme acyl carrier reductase
inhA gene
Can be used alone for LTBI (latent tb infection) given for close contacts
Isoniazid
Causes peripheral neuritis and hemolysis in G6PD deficient patients
Isoniazid
Given as a supplement to prevent restlessness, muscle twitches, insomnia
Pyridoxine (vit b6)
R Analog preferred for AIDS patients
Rifabutin
R Analog given to those with Traveler’s diarrhea
Rifaximin
Causes Red-orange pee and induces liver drug-metabolizing agents
Other effects: Skin rashes, thrombocytopenia, nephritis, liver dysfunction, Flu-like symptoms, anemia
Rifampicin
TB Drug that needs dose adjustment/reduction for those with renal failure
Ethambutol
What gene mutates when ethambutol is used alone
emb gene
Causes visual disturbances: decreased acuity, R-G colorblindness, optic neuritis, retinal damage
Other effects: Headache, confusion, hyperuricemia, peripheral neuritis
Ethambutol
TB Drug capable of penetrating CNS
Pyrazinamide
Causes Joint pains and Asymptomatic hyperuricemia
Other effects: Myalgia, Gi irritation, rash, hepatic dysfunction
Pyrazinamide
First line TB drug not given when patient is pregnant
Pyrazinamide
Most active drug against M. leprae
Dapsone
Inhibits folic acid synthesis
Dapsone
Provides inhibitory plasma concentrations
Alternative drug for P. carinii pneumonia in HIV patients
Acedapsone
Dapsone toxicity
Methemoglobinemia and Hemolysis in G6PD patients
Clofazimine toxicity
Discoloration of the skin and conjunctiva
Stored widely in reticuloendothelial tissues and skin
Clofazimine
Half-life of clofazimine
2 months
Phenazine dye used for multibacillary leprosy
Clofazimine
Drugs for NTM
Tetracyclines
Macrolides
Sulfonamides
Treatment of MAC
Azithromycin/Clarithromycin + Ethambutol/Rifabutin
MAC prophylaxis
Azithromycin/Clarithromycin