CD 09 Flashcards
Erythromycin commomnly cause GI disturbances ?
True
Azithromycin Clarithromycin better tolarated
Gentamycin is not active when given orally
All aminoglycosides are needed to given IV or IM route. Because they can not absorb from the GI tract and so given Parenterally.
Ciprofloxacin interects with theophylline used for asthma management
True. cpro inhibits hepatic metabolism of theophylline and increase its toxicity
Tetracycline should be avoided in pregnency and in your children
True, Tetracycline chelate Ca2+ and cause disclolouration of growing teeth
What are the selective drug target of a bacteria
- Bacterial cell wall
- Cell membrane
Structure of Gram Negative Bacteria is a bit complex which has
- Inner membrane
- Peptidoglycan (Cell wall)
- Outer Membrane
The sturecture of Gram positive is a bit simple it has
- Inner membrane
- Peptidoglycan
What is bacteria peptidoglycan (murein) has
A 3D meshwork of peptide cross linked sugar polymers
Why bacterial cell wall has peptidoglycan?
Peptidoglycan (Murin) Is important for bacterial survival
It gives rigidity and structure to the bacteria, so that, it can protect against osmotic gradient so they don’t burst.
How Peptidoglycan biosynthesis work?
- Cytoplasm (Synthesis of Murein monomers) =>
- Membrane (export to the inner membrane and flipped externally)=>
- Then peptidoglycan polymer cross-linking of glycan strands.
What is beta lactams common
The RING is the common but the other group attached to the ring is quite unique. Those Unique sturcture around the ring gives different spectram of activity
MoA of Beta lactams
- Inhibit peptidoglycan (As a result no cross-linking)
- Target penicillin-binding proteins (PBPs)
All bacteria have several PBPs i.e E.coli has at least 7 PBPs which helps to maintain the rod-like shape of E.coli. Beta-lactam
Inhibit septum formation as a result of no division or lysis.
Several Factors influence the activity of beta lactams those are?
- Resistance
- Enzymatic destruction i.e Beta lectamase enzyme from bacteria, distroy the beta lectam ring of the drug.
- Biofilms (Biofilms Produce more polysaccharide as a result hard to penetrate.)
- Density and age of infection.
Need higher con and longer for older infaction, coz they might have more resistance bacteri,or those bacteria can make more beta lectamase enzyme.
Penicillins (ampicillin, amoxicillin, flucloxacillin) cidal or static?
BacteriCidal
-Frequently administered with beta lactamase inhibitor (clavulanic acid, sulbactam)
Clavulanic acid (poor intrinsic antimicrobilal activity) Combined with amoxicillin (Augmentin)
- “Suicide” inhibitor
- Irreversibly binds to beta lactamases
- Oral, also parenteral
Penicillins
e.g. ampicillin, amoxicillin, flucloxacillin
-BacteriCIDAL
Pharmacokinetics of Penicillins
e.g. ampicillin, amoxicillin, flucloxacillin
Given orally
Excreted by urine
t1/2 short (30-60mins)
Unwanted effects of Penicillins
e.g. ampicillin, amoxicillin, flucloxacillin
Hypersensitivity (1-10%)
GI (kill to gut flora) diarrhoia
Rash