Antibiotics 2b Flashcards
Protein synthesis inhibitors generally have a (blank) effect by disrupting (blank)?
Bacteriostatic effect by disrupting translation (either 30s or 50s)
Which antibiotics inhibit the 30s subunit? (1)
Tetracyclines
Which antibiotics inhibit the 50s subunit? (2)
Chloramphenicol
Macrolides
Aminoglycosides (6)
Streptomycin Gentamicin Kanamycin Amikacin Tobramycin Neomycin
Aminoglycoside spectrum of activity
Static or killer?
Broad spectrum of activity
Bactericidal
Aminoglycosides are often combined with which other antibiotic class? Why?
Combined with B-lactam
Treat serious Gram negative infections
MOA of aminoglycosides
Bind to 30s subunit and disrupt initiation of peptide formation
Key adverse effects of aminoglycosides (2)
Nephrotoxicity
Ototoxicity
Name the three macrolides
Erythromycin
Clarithromycin
Azithromycin
Macrolide spectrum
Mostly GRAM + and SOME GRAM -
Macrolides- bacteriostatic or bactericidal?
Bacteriostatic at LOW CONCENTRATIONS
Bactericidal at HIGH CONCENTRATIONS
MOA of Macrolides
50s inhibitors thus preventing ELONGATION
Key adverse effect of macrolides?
Why?
GI UPSET (N/V/D) Macrolides are motilin receptor agonists
Name 4 Tetracyclines…if you can’t name 1 you go home and slap your face
Tetracycline
Minocycline
Tigecycline
Doxycycline
Spectrum of tetracyclines? Static or killer?
Broad spectrum that exerts a BACTERIOSTATIC effect
MOA of tetracyclines?
30s inhibitors…prevents ELONGATION of peptide chain
Nutrient interaction of tetracyclines? Based on this, which population should avoid these drugs?
Binds CALCIUM which results in growth of calcified tissue and turns teeth brown
May not want to use in CHILDREN, TEENAGERS, or PREGNANT WOMEN
Key adverse effects (2) of tetracyclines
- Disrupts normal flora
2. Photosensitivity
Clindamycin MOA
Inhibits the 50s subunit preventing INITIATION COMPLEXES and TRANSPEPTIDATION
Clindamycin spectrum of activity
NARROW spectrum
Anaerobic infections, aspiration pneumonia, anaerobic infections
Soft-tissue infections, community acquired MRSA
Key adverse effect of Clindamycin
Makes a patient more susceptible to C. diff infection
pseudomembranous colitis
Chloramphenicol spectrum? Static or killer?
BROAD spectrum that exerts a BACTERIOSTATIC effect
Chloramphenicol use? (3)
Serious infections such as typhus and Rocky Mountain Spotted Fever…also eye infections
MOA of chloramphenicol
50s subunit inhibitor (prevents translocation)
Key adverse effects (2) of chloramphenicol
RBC production suppression
Gray Baby Syndrome due to glucironic acid conjugation deficiency
The only oxazolidinone is…
Linezolid
Linezolid spectrum of action
Effective against MOST GRAM + but is NOT EFFECTIVE AGAINST FOR MOST GRAM -
Linezolid primarily used for
Treating bacterial strains resistant to penicillin, methicillin, and vancomycin
MOA of linezolid
50s inhibitor by preventing formation of the ribosomal-fMET-tRNA complex (step 1)
Key adverse effect of Linezolid
Myelosuppression
Name all classes or protein synthesis inhibitors
Aminoglycosides Macrolides Tetracylcines Clindamycin Chloramphenicol Oxazolidinones
DNA Synthesis Inhibitors–Antifolate Drugs
Sulfonamides (3)
Sulfadiazine
Sulfamethoxazole
Sulfamethizole
How are sulfonamides effective?
Bacteria must synthesize their own folate while mammalian cells do not. Sulfonamides block the folate synthesis pathway early one
MOA of sulfonamides
Sulfonamides compete with PABA and inhibit dihydropteroate synthase thereby inhibiting dihydrofolic acid synthesis…thereby ending DNA synthesis
Resistance to sulfonamides
Bacteria may produce excess PABA and outcompete the sulfonamides
Adverse effects of sulfonamides:
Skin
Urinary Tract
Skin- photosensitivity and STEVEN JOHNSON SYNDROME
Urinary tract: Sulfonamides precipitate in urine which can cause an obstruction
Sulfonamide use in UTIs
Sulfonamides DO PRECIPITATE in urine which is why they are good at treating UTIs
Trimethoprims (2)
Trimethoprim
Pyrimethamine
Spectrum of activity for trimethoprims
GRAM NEGATIVE bacteria
Resistance to TMPs
Resistance may occur if there is a change in drug uptake or reduced reductase binding
MOA of TMPs
Inhibitor of BACTERIAL DIHYDROFOLATE REDUCTASE resulting in impaired DNA synthesis
Key adverse effect of TMPs
Blood-
Myelosuppression
TMP-SMX is commonly used to treat (2)
UTIs
Prostatitis
MOA of TMP-SMX
Synergistic inhibition activity of DNA synthesis
Fluoroquinolones (2)
Ciprofloxacin
Levofloxacin
Spectrum of fluoroquinolones
BROAD spectrum against GRAM + and GRAM -
Fluoroquinolone uses (5)
Urinary GI Respiratory STDs Bioterrorism (anthrax)
MOA of fluoroquinolones
Specifically INHIBIT TOPOISOMERASE II and TOPOISOMERASE IV
Adverse effects of fluroquinolones
GI, nutrient, cardiac
GI: N/V/D
Nutrient interaction: bind divalent cations and neither get absorbed
Cardiac: QT prolongation
Group 1 fluroquinolones (1) and spectrum
Norfloxacin- lease active fluroquinolone
Group 2 fluroquinolones (3) and spectrum
Ciprofloxacin, levofloxacin, and ofloxacin
Works well against GRAM -
Some activity against GRAM +
Group 3 fluroquinolones (3) and spectrum
Getifloxacin, gemifloxacin, and moxifloxacin
Best activity against GRAM +
Metronidazole MOA
Not sure really…works well against bacteria and protozoa.
Definitely is a prodrug
Metronidazole spectrum
Limited to ANAEROBIC bacteria
Metronidazole uses (4)
- Abdominal infections
- Vaginal infections
- C. DIFF
- Brain abscess
Metronidazole key adverse effect
Metabolism- disulfram effect (avoid alcohol)
Lipopeptides target the…
Cell membrane
Only lipopeptide
Daptomycin
Spectrum of daptomycin
GRAM + bacteria
Daptomycin uses (3)
- Complicated skin and soft tissue infections
- Bacteremia
- Endocarditis
MOA of daptomycin
Binds to and causes depolarization of the MEMBRANE. Ultimately, daptomycin is BACTERICIDAL
Key adverse effects of daptomycin (1)
Patient may complain of muscle soreness
Detergent targeting cell wall
Polymyxin B
Polymyxin B often combined with (blank) to treat (blank)
Combined with bacitracin to skin infections
MOA of polymyxin B
Binds to phospholipids in cell membrane and disrupt structure
