Quinolones Flashcards
Examples of fluroquinolones?
Ciprofloxacin
Levofloxacin
Moxifloxacin
Mechanism of action of fluroquionolones?
Targets DNA gyrase in gram neg, topoisomerase IV in gram pos bacteria to inhibit DNA replication
For fluroquinolones,
a) administration
b) absorption
c) distribution
d) clearance
a) oral, IV, opthalmic
b) well absorbed after oral ingestion; NO to calcium or divalent cations 2h before medication
c) high in bone, urine (sans moxi-), kidney, prostatic tissue
d) renal
target organisms of fluroquinolones. types of infection.
C - gram neg, p. aeruginosa, e. coli, salmonella, shigella, campylobacter jejuni, bacillus anthracis, penicillin + cephalosporin + aminoglycoside resistant strains
travellers diarrhoae, food poisoning, skin, bone and joint infection, prostatis
L & M - same but + gram pos (s. pneumonia) + atypicals (m. pneumoniae, chlamydia pneumoniae, m. tb)
What infections are not indicated for use by fluroquinolones
UTI, MRSA, Anaerobic Infections, Strep, Enterococci Infection
adverse effects of fluoroquinolones
GI effects (nausea, vomiting, diarrhoae)
C. Diff Colitis (esp cip)
Headache, Dizziness, Light Headedness
Phototoxicity
Tendinitis or tendon rupture (NO to kids < 18)
Prolonged QT interval
Peripheral neuropathy
drug interactions of fluroquinolones.
increase theophylline, warfarin, cyclosporine
use of fluroquinolones in pregnancy
restrcited use. not use during breastfeeding
shd pt with MG take fluroquinolones?
no
3 types of anti-folate drugs.
1) sulfonamides
2) trimethoprim
3) co-trimoxazole
mechanism of action of the 3 anti-folate drugs
1) blocks dihydropteroate synthase
2) blocks dihydrofolate reductase
3) blocks both
for sulfonamides,
a) absorption
b) distribution
c) metabolism
d) excretion
a) oral, mostly well absorbed except sulfasalazine
b) bound to serum albumin; penetrate into CSF well even without inflammation
c) liver
d) renal, breast milk
uses of sulfonamides
- combined with co-trimoxazole for p. jirovecii
- combined with pyrimethamine for drug-resistant malaria and toxoplasmosis
- sulfasalazine in IBD
- infected burns
- respiratory infectioms
- acute UTI
adverse effects of sulfonamides.
- crystalluria
- hypersensitivity
- hematopoietic disturbances
- kernicterus (NO to newborns and infants < 2m and pregnant women at term
drug interactions of sulfonamides.
potentiation of anticoagulant effect of warfarin (displacement from binding sites on serum albumin)
clinical uses of trimethoprim. types of infection
enterobacter, e. coli, klebsiella pneumoniae/ UTIs and prostatitis (2nd line to fluroquinolones)
for trimethoprim:
a) absorption
b) distribution
c) excretion
a) oral
b) widely distributed thruout body inc CSF; weak base so higher conc in acidic conditions
c) renal
resistance of trimethoprim
altered dihydrofolate reductase
efflux pumps
decreased permeability
adverse effects of trimethoprim
- folic acid defiency sequelae
- megaloblastic anemia
- leukopenia
- granulocytopenia
how to reduce adverse effects of trimethoprim
effects can be reversed by simultaneous administration of folinic acid
what is the combination for cotrimoxazole and in what ratio
trimethoprim and sulfamethoxazole (1:5)
for cotrimoxazole,
a) administration
b) distribution
c) clearance
a) oral; IV (for severe pneumonia or UTI when pt unable to take drug orally)
b) distributes well thruout, esp in prostatic fluid
c) urine
targets for co-trimoxazole:
- E. Coli in UTIs
- Hemophilus, Moraxella catarrhalis, Klebsiella pneumonia in Respiratory Tract Infections
- Toxoplasmosis
- MRSA and community-acquired skin and soft tissue infection
- Pneumocystis pneumonia by P. jiroveci
adverse effects of co-trimoxazole
- rash
- photosensitivity
- GI effects (nausea + vomiting)
- Glossitis and stomatitis
- Hemolytic anemia in pt with G6PD deficiency (due to sulfamethoxzaole)
- folic acid deficiency sequelae (megaloblastic anemia, leukopenia, thrombocytopenia)
use of co-trimoxazole in pregnancy.
NO in 1st trimester (folic acid deficiency can cause dvt issues) and last trimester (worried for G6PD in children)
drug interaction of co-trimoxazole
increase half life of phenytonin, enhance effect of warfarin
Mechanism of action of nitrofurantoin?
bacteria will reduce drug to a highly active intermediate that inhibits various enzymes and disrupt synthesis of proteins, DNA, RNA and metabolic processes
target organism of nitrofurantoin?
- e. coli
- enterococci
NO vs proteus, pseudomonas, enterobacter, klebsiella
for nitrofurantoin,
a) administration
b) absorption
c) distribution
d) elimination
a) oral
b) rapid from GI tract
c) high urinary conc while limiting systemic exposure (due to rapid clearance) - good for UTIs
d) urine; acidic urine enhances drug activity
adverse effects of nitrofurantoin?
- GI effects (nausea, vomitting, diarrhea)
- hypersensitivity
- leukopenia, hemolytic anemia (a/w G6PD deficiency)
- Cholestatic jaundice and hepatocellular damage (nitro-reductive metabolism produces injurious oxidative free radicals which damage hepatocytes) – note there may be prolonged incubation period to onset of liver injury, may lead to mistaken or delayed diagnosis
- Pulmonary toxicity (elderly pt)
- peripheral neuropathies (for pt with impaired renal functions or on long term treatment)
