Protein Synthesis Inhibitors Flashcards
1
Q
What are 6 facts about Doxycylcin (Tetracycline)?
A
- Binds reversible to 30s ribosome, blocking binding of tRNA (bacteriostatic)
- Active against gram + (some S. aureus and S. pneumoniae, community acquired MRSA)
- Good for tick borne illness and syphilis if PCN allergy
- great bioavailability but decreased absorption with cations
- primarly eliminated through intestinal tract, no dose adjustment needed with renal dysfunction
- Resistance from active efflux or 30s targt site modification
2
Q
What are 4 advserse effects from Tetracyclines?
A
- yellow/brown discoloration of teeth in children
- nause, esophageal ulceration (“pill esophagitis”), hepatotoxicity
- Photosensitivity
- Cross placenta and accumulate in fetal bone and teeth
3
Q
What are 6 facts about Gentamicin (Aminoglycosides)?
A
- Irreversibly binding and inhibit 30s ribosome (bactericidal)
- main activity against gram - bacilli (mainly for severe gram - infections and can combine with beta lactam therapy so able to penetrate cell wall–synergy)
- IV
- renal excretion
- Concentration depedent killing (unlike beta lactams that just need to be slighlt above MIC, this needs to have peak MIC to have effective killing)
- Resistance: inactivating enzyme, active efflux pump, ribsomal mutations
4
Q
What
What are 2 adverse effects of Gentamicin (Aminoglycosides)?
A
- Nephrotoxicity: filtered across the glomerulus with partial reabsorption in prximal tubule
- Ototoxicity: vestbular (vertigo) and cochlear (hearing loss)
*narrow theraputic index and need to monitor serum drug levels
5
Q
What are 3 macrolides?
A
- Erythromycin
- Clarithromycin
- Azithromycin
6
Q
What are 5 facts about Macrolides?
A
- Binds to 50s ribosome (bacteriostatic)
- Resistance mech: efflux pump and target site ribosomal RNA
- use against S. pneumoniae and S. aureus (community acquired pna)
- Good for H. influenza (upper respiratory tract infections) and atypial pneumonias
- Good for strep throat and PCN allergy
7
Q
What are 5 facts about erythromyocin?
A
- IV and oral preparations
- Short half life
- inactivated by gastric acid so enteric coated prep
- inhibitor of CYP450
- Excreted in stool
8
Q
What are 5 adverse effects of erythromycin?
A
- safe and inexpensive
- cramps, nausea, vomiting, diarrhea
- Hepatotxic (liver inflammation)
- GT prolongation
- Drug-drug interactions because inhibitor of CYP450
9
Q
What are 5 facts about azithromycin and Clarithromycin?
A
- Developed to overcome limitations of erythromycin
- improved oral obsorption and longer serum half life
- same mech of action and similar spectrum to erythromycin
- fewer adverse effects than erythro (less GI effects but same drug interactions and QT longation)
10
Q
What are 6 facts about fidaxomicin?
A
- 1st lone drug to treat c. diff
- no absorbed/no systemic effect/minimal adverse effects
- Narrow spectrum
- spared normal flora of GI tract
- expensive but associated with reduced recurrence of c. diff
- ribosomal inhibitor
11
Q
What are 5 facts about Clindamycin?
A
- binds to 50s ribosomal subunit (inhibits elongation/can inhibit toxin production)
- approved for tx of anaerobic, gram + infections in PCN allergy, gram - (staph/strep)
- can use oral
- intraabdominal and skin infections
- resistance: efflex pump, target site modifcation, enzymatic inactivation
12
Q
What are 3 facts about distributions and adverse effects of clindamycin?
A
- Wel absorbed after oral administration
- excellent bone penetration
- Adverse effects: GI discomfort, diarrhea, rash (can cause abx associated diarrhea, including c. diff)
13
Q
What are 4 facts about Linezolid?
A
- Bind to 50s ribosome and prevent formation of initiation complex
- Active against Gram + (MRSA and VRE), used for resistant gram + infections
- resistance rare
- excellent oral bioavailability
14
Q
What are 3 adverse effects of linezolid?
A
- bone marrow suppression (decreased WBC, RBC if given for more than 14 days)
- Serotonin syndrome (excess serotonin, people on SSRIs more susceptible)
- Peripheral neuropathy
