Anti- microbials Flashcards
What is the main target of anti-microbials
The bacterial cell wall
Two groups of cell wall active agents
Beta lactams
Glycopeptides
Examples of Beta lactams
Penicillins
Cephalosporins
Monobactams
Carbapenems
Examples of Glycopeptides
Vancomycin
Teicoplanin
Anti-microbials that act on nucleoside precursors
Trimethorpim
Sulphonamides
Anti-microbials that act on nucleic acid synthesis
Metronidoazole
Quinolones
Rifampicin
Nitrofurans
Anti microbials that are protein synthesis inhibitors
Aminoglycosides Tetracyclines Macrolides Oxazolidinones Fusidic acid
Mode of action of penicillin
Interfere with bacterial cell wall peptidoglycan
Attach to penicillin binding proteins
Inhibit transpeptidase enzyme activity
Inactivate inhibitor of autolytic enzyme in the cell wall - causing lysis
Treatement for bacterial meningitis
Benzyl penicillin
Penicillin used for resp infections UTI and ottis media
Broader spectrum - amoxicillin
what type of penicillin is fluoxacillin and what does it treat
Beta-lactamase
cellulitis
Penicillin used to treat severe infections/pseudonomas
Piperacillin
Extended spectrum
The pharmokinetics of penicillin’s
Oral absorption variable
Widely distributed in body fluids
Mainly renal excretion
short plasma half-life
Adverse affects of penicillin
hypersensitivity
anaphylaxis
oral antibiotic associated diarrhoea
Structure of cephalosporins
Chemically structurally similar to penicillin
Mode of action of cephlopsorins
Similar to penicillins
Why is there a greater resistance to cephalosporins
due to them being gram -ve
What excretes cephalosporins
Kidney
what cephalosporin should be used for meningitis
ceftotaxime
What cephalosporin should be used for bronchiectasis infections
ceftazidime
Examples of macrolides
Erythromycin
Clarithromycin
Azithromycin
Mode of action of macrolides
Inihibit bacterial protein synthesis
Bind to 50S subunit of bacterial ribosome and prevent transolocation of growing peptide chain
How are macrolides administered
Usually PO
What are the benefits of macrolides
benefits against atypical pneumonia /COPD benefits
Adverse effects of macrolides
GI upset
Hypersensitivity
QT prolongation - arrhythmic
Why do macrolides interact with other drugs?
Due to their effects on cytochrome P450
Examples of quinolones
Ciprofloxacin
Levofloxacin
Moxifloxacin
Mode of action of quinolones
Inhibits bacterial DNA gyrase
Prevents DNA double helix being supercoiled - no transcription and replication
Features of quinolones
Well absorbed
Good active against Gm -ve coliforms awell as H. influenza and pseudomonas
What do quinolones act poor against
strep pneumonia and staph
What are quinolones usually used for
UTI and pneumonia and levofloxacin
What are adverse affects of quinolones
GI Hypersensitivity Caution of QT prolongation Inhibits CYP 450 - increase theophylline toxicity Rare convulsions