Antibiotics Flashcards
Name 4 antibiotic targeted mode of actions?
- Cell wall
- DNA
- Protein synthesis
- Mycobacterium
Name an antibiotic used that is a fungus
Penicillin
It causes the bacterial cell wall to rupture by autolysis.
What is the site of action for penicillin?
Transpeptidase
How does Penicillin work?
It works by binding to active site on the transpeptidase to inhibit its ability to cross link the peptiglycan. Making the cell wall more flexible and susceptible to regenerate which affects the cell membrane.
What kind of antibiotics are penicillins and why?
They are B-lactam antibiotics as they contain a B-lactam ring.
Are penicillins enzyme inhibitors?
Yes, they are irreversible enzyme inhibitors.
Name 4 types of penicillin
1) Penicillins
- Pen V
- Pen G
2) Broad spectrum
- Ampicillin
- Amoxicillin
3) B-lactamase resistant
- Flucoxacillin
- Co-amoxiclav
4) Anti-pseudo-monal
- Piperacillin with tazobactin
Give 3 facts for Phenoxymethylpenicillin (Pen V)
1) Effective against gram -
2) Narrow spectrum of activity therefore does not affect the gut area.
3) Variable absorption from the GI tract.
Give 4 facts for Benzylpenicillin (Pen G)
1) Effective against gram +
2) Unstable in acid, must only be given by IV/IM
3) Given in large doses and for severe infections
4) Given for following infections:
- Streptococcal (Pneumonia and endocarditis)
- Clostradia (tetanus)
- Meningococcal (meningitis and septisemia)
When would you prescribe Pen V?
Phenoxymethylpenicillin is prescribed to treat infections such as chest infections, tonsillitis, cellulitis, ear infections, and dental abscesses. It is used in particular for respiratory infections in children
Name 2 broad spectrum antibiotics
- Amoxicillin
- Ampicillin
When would you prescribe amoxicillin?
Amoxicillin is an antibiotic used to treat a number of bacterial infections. These include middle ear infection, strep throat, pneumonia, skin infections, and urinary tract infections among others.
What can Ampicillin cause?
1) Overgrowth of C.diff
2) Diarrhoea due to it being broad spectrum
3) Not metabolised by stomach acid
What are broad spectrum antibiotics used for?
- Pneumonia
- UTIs
- HAP
- H Pylori related infections
- Peptic ulcers
What are two side effects of penicillins?
1) Hypersensitivity
2) Neurotoxicity
How can penicillins cause Neurotoxicity?
When it gets to the brain, influences GABA-A receptor. thus, leading to seizures.
How can penicillins cause Hypersenstivity?
Hypersensitivity is classified into 3 types:
1) Immediate reactions
- 20 mins
- Mediated with IgE
2) Accelerated reaction
- 1-72 hours
- consists of urticaria
3) Late reaction
- 72 hours to several weeks
- usually a skin rash
How should penicillins be NEVER administered and why?
Intrathecal injection, cause a seizure.
Name 4 Cephalosporins
1) Cefalexin
2) Cefradine
3) Cefaclor
4) Cefradoxil
How do Cephalosporins work?
They work by inhibiting peptidoglycan cross linking.
They are more resistant to B-lactamases than penicillins. Therefore, 2nd/3rd line of treatment for Resp/UTI.
When can IV Cephalosporins be used?
Only for severe/complicated antibiotic resistance.
What are side effects of Cephalosporins?
1) Can cause diarrhoea
2) Hypersenstivity
3) Seizures
4) Vitamin K deficiency
- Reduces bacteria in the gut that produces Vit K
How should Cephalosporins be prescribed to patients with kidney impairment?
Should be given in less dose
What are carbapenems?
- Resistance against B-lactamases.
- Resistant against gram - & +
Which carbapenems is broad spectrum?
Meropenem (gram - & +)
Which carbapenems is less broad spectrum?
Ertapenem
Give one advantages of carbapenems?
Longer duration of action
What are monobactams?
Monobactams are a subgroup of beta-lactam antibiotics, where the beta-lactam ring is alone (not attached to another B-lactam ring)
What do they work against?
They only work against aerobic gram -
Must only be given IV/IM
How do monobactums work?
Monobactams work by inhibiting the peptidoglycan synthesis process; as a result, the bacteria lose the ability to resist and burst, leading to cell death.
Give examples of monobactums
Azactam
Aztreonam
Aztreonam inhalation
What is vancomycin used for?
Gram positive infections
- Endocarditis
- Antibiotic associated colitis (caused by C.diff)
How does vancomycin work?
It works by inhibiting growth and cross linking of peptidoglycan.
Inhibiting synthesis of the cell wall of gram +, thus killing the bacteria.
Affects the polymerisation of the sugar layer.