Macrolide

Question 1

Macrolides

Answer 1

Azithromycin:

Mechanism of action:
inhibits protein synthesis
bacteriostatic
bactericidal in higher doses

Clinical application:
atypical coverage
mycoplasma and chlamydia

Gram-positive organisms
CAP and respiratory tract infections
pertussis
Legionnaires disease
diphtheria

Avoid use :
Limited gram negative and streptococcus pneumonia

Side effects:
Prolonged QT , ventricular tachycardia, pancreatitis , hepatoxicity , C diff , myasthenia gravis exacerbation

Question 2

Quinolones

Answer 2

Ciprofloxacin

Mechanism of action:
cause bacterial cell death
inhibit enzymes that mediate DNA supercoiling, transcription, and repair

Clinical application:
gram + cocci
gram - bacilli
atypical bacteria
Anaerobes: moxifloxacin avoid with UTI
UTI
non-gonococcal infections of the urethra and cervix
upper and lower resp
soft tissue infection
prostatitis
anthrax +++

Side effects
c diff, increased resistance, retinopathy , tendinopathy, prolonged QTC , aoritc dissections/rupture

Question 3

Aminoglcosides

Answer 3

Gentamicin:

Mechanism of action:
bind negative charges in outer phospholipid membranes
displaces cations
inhibit protein synthesis by binding to the 30S subunit ribosome

Application:
Aerobic gram-negative bacilli
UTI
resp tract
skin and soft tissues
sepsis due to gram-negative aerobic bacilli

side effects;
renal failure ( most common ), vestibular and auditory impairment
neuromuscular blockage

Question 4

Nitroimidazole

Answer 4

Flagyl:

mechanism of action
promotes the formation of intermediate compounds and free radicals
cytotoxic - intermediate particles fatal to DNA helix

Clinical application:
anaerobes ++++
travelers diarrhea
giardia lamblia

urethritis /STI
trichomonas vaginalis

Avoid:
C diff

side effects
GI and neuro findings
metallic taste, furry tongue, glossitis, stomatitis, seizures, peripheral neuropathy, dizziness, encephalopathy

Question 5

antibiotic sodium load

Answer 5

selected intravenous and oral prescription medication high in sodium :
ampicillin /sublactam injecion
alendronate
azithromycin
erythromycin
metronidazole
omeprazole/sodium bicarbonate
oxacillin injection
piperacillin / tazobactam
polyethlene glycol power solution ( golytely)
ranitidine
sodium phosphate solution enema

Question 6

fallacies in antibiotic therapy

Answer 6

1. broader is better
2. failure to respond is a failure to cover
3. when in doubt, change drugs or add another ( expect 3 days of therapy before you see a response)
4. more diseases, more drugs
5. sickness requires immediate treatment
6. response implies diagnosis
7. more extensive disease, more extensive drugs
8. bigger disease, newer drugs
9. antibiotics are non-toxic