Antimycobacterial Drugs Flashcards
treatment of active TB
4 drugs- isoniazid rifampin pyrazinamide ethambutol
treatment of MDR-TB
5-6 drugs
latent TB treatment
isoniazid or rifampin alone for 9 months
locations of TB drugs
intracellular
extracellular
cavities
speed of intracellular replication
slow
speed of extracellular replication
fast
speed of cavitary replication
slow
mycolic acid
long chain branched fatty acids in the wall
mycelia acid benefits
resist dehdyration, disinfectants, antibiotics, hide from macrophages
isoniazid works at
extra
intra
cavity
isoniazid is cidal or static
either- depends on location
isoniazid MOA
prodrug activated to nicotinoyl radical by Katg which inhibits mycolic acid synthesis by blocking InhA and KasA
KatG
mycobacterium enzyme that activates isoniazid to nicotinoyl radical
nicotinoyl radical
active form of isoniazid
InhA
acyl carrier protein reductase
KasA
acyl carrier protein synthetase
isoniazid resistance mechanisms
spontaneous resistance
KatG mutation
InhA overexpression
resistance to oxidative stress
isoniazid clearance
NAT2 aceylation in liver which is then either excreted by kidney oR converted to hydrazine by cops
acetylated and excreted
what increases isoniazid toxicity
slow acetylators
cyp inducers
isoniazid side effects
hepatotoxicity
neurotoxicity- PNS and CNS
prevention of isoniazid side effects
B6 supplements
isoniazid interactions
inhibits MAO- do not give with tyramine foods, excessive caffeine, MAOI
cyp inhibitors
alcohol
extracellular acting first line tb drugs
isoniazid
rifampin
ethambutol
streptomycin
intracellular acting first line tb drugs
isoniazid
rifampin
pyrazinamide
cavity acting first line tb drugs
isoniazid
rifampin
ethambutol
rifampin acts in
intracellular
extracellular
cavity
rifampin cidal or static
cidal
rifampin MOA
inhibits bacterial RNA polymerase
rifampin resistance
RNA polymerase mutations
rifampin clearance
deacetylation in liver
specific isoniazid CNS effects
memory loss
psychosis
seizures
specific isoniazid PNS effects
paresthesia of hands/feet
rifampin ADR
elevated AFT- rare hepatotoxicity
turns secretions red
thrombocytopenia
hypersensitivity rxn
rifampin interactions
cyp inducer- MANY drug interactions
oral contraceptives
warfarin
protease inhibitors
rifapentine
same as rifampin but longer half life and fewer drug interactions
pyrazinamide acts where
intracellular
pyrazinamide cidal or static
cidal
pyrazinamide MOA
prodrug- converted by pyrazinamidase (bacterial deaminase) to pyrazinoic acid
disrupts membrane function and transport
pyrazinamidase
enzyme that activates pyrazinamide
pyrazinoic acid
active form of pyrazinamide
resistance mechanism for pyrazinamide
pyrazinmidase mutation
elimination of pyrazinamide
kidney
pyrazinamide ADR
hepatotoxicity
hyperurecemia
most hepatotoxic first line tb
pyraziamide
pyramidamide interactions
none
ethambutol acts
extracellular
cavities
ethambutol MOA
inhibits arabinagalactan synthesis
arabinagalactan synthesis
anchor for mycolic acid
ethambutol resistance
mutation in target enzyme
ethambutol clearance
renal
ethambutol ADR
optic neuritis
hyperuricemia
hepatotoxic first line tb drugs
isoniazid
pyrazinaide
hyperurecemia is in what first line tb drugs
pyrazinamide
ethambutol
optic neuritis is in what first line tb drug
ethambutol
streptomycin acts wehre
extracellular
streptomycin cidal or static
cidal
streptomycin MOA
binds 30S subunit and causes mRNA misreading
streptomycin resistance
rRNA and protein mutations
streptomycin elimination
renal
streptomycin ADR
ototoxicity- vestibular and auditory
nephrotoxicity
ototoxic first line tb
streptomycin
nephrotoxic first line tb
streptomycin
weakest first line tb
ethambutol
neurotoxic tb drugs
isoniazid
cycloserine
ethioamide
what is given to prevent neurotoxicity
pyridoxine
what drugs is pyridoxine given with
isoniazid
cycloserine
cycloserine cidal or static
both
cycloserine MOA
inhibits peptidoglycan synthesis
cycloserine clearance
renal
cycloserine side effects
neurotoxicity
peripheral neuropathy
CNS- anxiety, depression, psychosis, memory loss, seizures
cycloserine contraindicated in
psychosis
alcoholism
epilepsy
renal impairment
ethionamide cidal or static
both
ethionamide MOA
prodrug- inhibits InhA (mycolic acid synthesis)
ethionamide ADR
GI upset
CNS toxicity- depression, sensory disturbances
hepatitis
amino salicylic acid static or cidal
static
amino salicylic acid MOA
inhibits thymine nucleotide synthesis
aminosalicylic ADR
GI upset
hypersensitivity
drugs causing GI upset
Ethambumide
aminosalicylic acid
bedaquiline use
MDR only- with 3 other drugs known to work
bedaquiline moa
inhibits ATP synthase
bedaquiline elimi
cyp metabolism
plasma bound
bedaquiline ADR
QT prolongation
elevated AFT
headache
arthalgia
QT prolongation
bedaquiline
drugs that inhibit InhA
isoniazid
ethionamide
leprosy drugs
rifampin
dapsone
length leprosy treatment
6-12 months
dapsone MOA
static, concentrated in infected skin
inhibits folate synthesis
inhibits neutrophil functioning
antioxidant
dapsone ADR
hemolysis- severe in G6PD deficiency
methemoglobinemia
drug affected by G6PD decifiency
dapsone
drugs for MAC
rifampin
ethambutol
aminoglycoside
length of MAC treatment
12 months after first negative culture