Antimicrobials dos Flashcards
Ribosome complex in bacteria
70s
Why are protein synthesis inhibitors toxic to humans at higher doses
bc at higher doses there is reduce selectivity (doesn’t only focus on bacteria)
Dose-dependent selectivity are major concerns for what 2 types of drugs?
Chloramphenicol
Tetracyclines
what does chloramphenicol bind to during PSI
50S subunit
What does Erythromycin bind to during PSI
50S
What are the 5 Aminoglycosides
Gentamycin Amikacin Tobramycin Streptomycin Neomycin
What mechanism do AMinoglycosides use?
Bind to 30S changin ts shape
WHat effect on mechanism does AMinoglycosides have?
1) Block initiation
2) Early Termination
3) Misreading
Whats the oldest aminoglycoside - so high level of resistance
Streptomycin
How is Streptomycin administered
IM
IV
What is the most commonly prescribed aminoglycoside?
gentamycin
Gentamycin method of delivery?
IV
What aminoglycoside has the broadest spectrum?
Amikacin
Amikacin method of delivery
IM
IV
What aminoglycoside is great against Pseudomonas aeruginosa?
Tobramycin
Tobramycin method of Delivery
IM
IV
What aminoglycoside is very toxic systemically?
Neomycin
Neomycin mthods of delivery
2
Topical
Enema
Clinical use for aminoglycosides
Gram Negative Aerobes
Neomycin is toxic to what in body?
Kidney
Nephrotoxicity
Risk of nephrotoxicity and ototoxicity with aminoglycosides is dependent on what?
COncentration
WHat are the sites of accumulation for Aminoglycosides
Inner ear
Renal Cortex Proximal Tubule Cells
WHat do aminogycosides synergize with and how?
Beta-Lactams
Vancomycin
Aminoglycosides are able to diffuse accross weakened bacterial cell wall more
Adverse effects of Aminoglycosides
5
1) Ototoxicity
2) Nephrotoxicity
3) Neuromuscular paralysis
4) Teratogenic
Contact Dermatitis
What patients are at highest risk of paralysis from Aminoglycosides
Patients with Myasthenia Gravis
Additional at risk groups for AMinoglycosides
1) Elderly
2) Impaired Renal Function
3) Septic Pts
4) Recent exposure to other Aminoglycosides
WHat are the 4 TTCs?
1) Tetracycline
2) Doxycycline
3) Minocycline
4) Tigecycline
Mechanism of TTCs
Reversably binds to 30 S
Thus blocking access of the amino acyl-tRNA tothe mRNA
Spectrum of TTCs
Gram +
Gram -
Atypical intracellular organisms
Are TTCs cross resistant?
YES!!
What TTC is effective when bacteria is cross resistant?
Tigecycline
Oral absorption of TTCs is altered by what?
Dairy
Iron supplements
Antacids
WHere does TTC concentrate?
Ca-hydroxyapatite of teeth and bones
What antimicrobial is used for treatment of acne vulgaris
Tetracycline
Should tetracycline be used during pregnancy?
NOOOOOO!!
Adverse effects of TTCs
1) Disulfuram-like effet - avoid alcohol!
2) Vestibular Problems
What TTC gives the most vestibular problems?
Minocycline
Oral adverse effects of TTC
hairy tongue
Deposition in bone and prmary dentition
Tigecycline spectrum
Same as TTCs plus activity against MRSA, Multidrug resistant Strp. pneumonae, Vancomycin-resistant Enterococci
Clinical use of Tigecycline
Developed to overcome TTC - resistance
3 macrolides are
1) Erythromycin
2) Clarithromycin
3) Azithromycin
Mechanism of Macrolides
Irreversibly binds to 50S
Thus inhibiting the translocation step
Spectrum of Macrolides
broad.
Gram +
Gram -
Atypical Bacteria
Do Macrolides have cross resistance?
YES!!
Clinical uses of macrolides
THey are very safe antimicrobials
Upper respiratory infections
COmmunity aquired pneumonia
Pts allergic to penecillin
_____ has been replaced by _______ and ______ for community aquired pneumonia bc of better activity and fewer adverse effects
- Erythromycin
- Clarithromycin
- Azithromycin
What is known as z-pack
azithromycin
WHat is the preferred therapy for urethritis due to CHalmydia
Azithromycin
WHat has the longest half-life and volume distributon of the macrolides
azithromycin
