Antimicrobials Flashcards
What drug classes inhibit cell wall synthesis?
Cephalosporins
Penicillins
Bacitracin
Which drug class inhibits the transfer of peptidoglycan?
Bacitracin
How do penicillins and cephalosporins inhibit cell wall synthesis?
Inhibit cross linking of peptidoglycan
Which drug classes inhibit the 30s protein subunit?
Aminoglycosides (tobra gent 30)
Tetracyclines
Which drug classes inhibit the 50s protein subunit?
“CCM”
Chloramphenicol
Clindamycin
Macrolides
What are the 2 aminoglycosides?
Tobramycin
Gentamycin
What drugs inhibit the synthesis of folic acid?
Sulfonamides
Trimethoprim
Pyrimethamine
What drugs interfere with DNA gyrase and Topoisomerase IV?
Fluoroquinolones
Which antimicrobial drug class has 2 mechanisms of action?
Fluoroquinolones
Most antibiotics have what side effects in common?
GI upset
Which drug inhibits the transfer of peptidoglycan into the cell wall?
Bacitracin (+)
What is bacitracin(+) most often used for?
Blepharitis
What 2 drugs make up polysporin?
Bacitracin(+) Polymyxin B (-)
What are the 2 penicillins for boards?
Amoxicillin
Dicloxacillin
What is the MOA of amoxicillin and dicloxacillin?
Inhibit transpeptidase (cross linking)
Amoxicillin and dicloxacillin have what gram coverage?
Amoxicillin (+)(-)
Dicloxacillin (+)
What combo make Augmentin?
Amoxicillin (+)
Clavulonic acid
Why is clavulonic acid added to augmentin?
Penicillinase inhibitor
Dicloxacillin is capable of handling which infection, MRSA or MSSA?
MSSA
What are the adverse effects of penicillins?
Hypersensitivity, including SJS
Are penicillins safe in pregnancy?
Yes
Why do cephalosporins and penicillins have cross sensitivity?
Both have a beta-lactam ring
What are the contraindications for penicillins?
Type 1 hypersensitivity
What are the 2 cephalosporins for boards?
Cephalexin (+)
Ceftriaxone (+)(-)
What is the cephalosporin MOA?
Inhibit transpeptidase
Which generation of cephalosporins add gram (-) coverage to go along with the gram (+) coverage?
Gen 3 and 4
Cephalexin should not be used in isolation if what infection is suspected?
MRSA
Which cephalosporin will have gram (-) coverage: Cephalexin or Ceftriaxone?
Ceftriaxone (+)(-)
-3rd generation cephalosporin
What are the possible adverse reactions to cephalosporins?
Destroy intestinal microflora
Alter absorption of Vit K - excess blood thinning when combined with warfarin
What are the aminoclycosides?
Gentamicin
Tobramycin
What is the MOA of aminoglycocides?
Protein synthesis inhibitor - block 30s subunit
What gram coverage do aminoglycosides offer?
Gram (-) (+)
Better (-) coverage than (+)
What drugs classes block the 30s subunit?
Aminoglycosides
Tetracyclines
Before the arrival of fluoroquinolones, what drug class was first-line therapy for ocular bacterial infections?
Aminoglycosides
What drugs work on the 50s subunit?
“CCM”
Chloramphenicol
Clindamycin
Macrolides
What are the 2 known adverse effects of aminoglycosides?
SPK
Delayed re-epithelialization
How do tetracyclines function as antibacterials?
Block the 30s subunit
Are tetracyclines bactericidal, or bacteriostatic?
Bacteriostatic
Why is doxycyline commonly Rxed for meibomianitis?
Decreases the release if free fatty acids
What are the 3 common reasons to Rx doxycycline?
Meibomianitis
Acne rosacea
Chlamydial ocular infections - trachoma, inclusion
Why are tetracyclines supposed to be taken without food?
Dairy, antacids, and iron impair GI tract absorption of tetracyclines
Which tetracycline is the exception to the “no food” rule?
Doxycycline
Why are tetracyclines contraindicated in renal failure?
Excreted via kidneys
Why is doxycycline safe in renal failure, when other tetracyclines aren’t?
Excreted in fecal matter
What are the contraindications of tetracyclines?
Pregnancy
Kids
Renal failure
What are the possible side effects of tetracyclines?
Pseudotumor cerebri Bone growth retardation (kids) Tooth discoloration (kids)
Minocycline has 2 additional adverse effects. What are they?
Blue sclera
Conj pigmented cysts
What are the 50s blocker drug classes?
“CCM”
Chlormaphenicol
Clindamycin/Lincomycin
Macrolides
What gram coverage does chloramphenicol offer?
Gram (+)(-)
What are the 2 major adverse effects of chloramphenicol?
Aplastic anemia - fatal
Optic neuritis
How do macrolides function as antibacterials?
50s subunit protein blockers
What are the macrolide drugs?
“ACE-mycins”
Azithromycin
Clarithromycin
Erythromycin
Why might azithromycin cause GI upset?
It is to be taken on an empty stomach
Which of the macrolides is commonly used as prophylaxis for neonatal gonorrhea?
Erythromycin
Why isn’t erythromycin used more frequently?
Resistance
Azithromycin (Azasite) contains what preservative, making it an issue in CL wearers?
BAK
How do clindamycin and lincomycin work as antibacterials?
50s subunit blockers
What 3 drugs are recommended for MRSA?
Clindamycin
Trimethoprim-sulfamthoxazole
Doxycycline
How do trimethoprim and pyrimethamine act as antibacterials?
Inhibit DHF reductase, stopping folate synthesis
DHF reductase catalyzes which step of folate synthesis?
2nd
Which drugs inhibit the first step of folate synthesis?
Sulfonamides
Are sulfonamides bacteriostatic or bactericidal?
Bacteriostatic
What gram coverage to sulfonamides offer?
Gram (+)(-)
What are the ophthalmic adverse effects attributed to sulfonamides?
SJS
Photosensitization
Contact dermatitis
Burning/stinging
What are the systemic adverse effects attributed to sulfonamides?
Myopic shift
SJS
Infant kernicterus
What drugs commonly induce SJS?
Sulfonamides
Amoxicillin
Trimethoprim-sulfamethoxazole
What gram coverage do trimethoprim and pyrimethamine offer?
Gram (+)(-)
Trimethoprim is not effective against which bug?
Pseudomonas
What are the common adverse reactions to trimethoprim and pyramethamine?
Bone marrow suppression
-aplastic anemia
What are the MOAs of fluoroquinolones?
Inhibit DNA gyrase
Inhibit Topoisomerase IV
What are the 2nd generation fluoroquinolones?
Ciprofloxacin
Ofloxacin
What is the 3rd generation fluoroquinolone?
Levofloxacin
What are the 4th generation fluoroquinolones?
Gatifloxacin
Moxifloxacin
Besifloxacin
As newer generations of fluoroquinolones arise, what gram coverage is increasing?
Gram (+)
Fluoroquinolones are known to be potent inhibitors of what gram bacteria?
(-)
What fluoroquinolones may be used orally?
Ciprofloxacin
Moxifloxacin
What are the adverse effects of oral fluoroquinolones?
Damage to cartilage formation
Inhibition of bone growth
Tendinitis
What are the contraindications of oral fluoroquinolones?
Pregnancy
Kids - under 18
Topical fluoroquinolones are approved for what age range?
> 1 year old
What are the bacteriostatic agents?
Tetracyclines
Trimethoprim
Sulfacetamide
Erythromycin
What are the bactericidal agents?
Penicillins Cephalosporins Bacitracin Aminoglycosides Fluoroquinolones