Antibiotics Flashcards
What are the Beta Lactam Antibiotics?
What do they do?
These are antibiotics which contain Beta Lactam Rings in their chemical structures.
Inhibit enzymes in the cell wall to cause bacterial cell death (Bactericidal)
Give examples of Beta Lactam Antibiotics
HINT: Think “-cillin”
Penicillin
Flucloxacillin
Amoxicillin
DON’T FORGET CEPHALOSPORINS - A SUBCLASS OF BETA LACTAMS
When should you not administer Beta Lactams?
Anaphylaxis
Occurs due to Degradation of the Beta Lactam Ring
Also in cases of resistance (obviously)
Why is it important to consider anaphylaxis with Beta Lactams?
Because if you are anaphylactic to one, you are likely to be anaphylactic to the rest.
Which is better absorbed; Oral Penicillin or Oral Amoxicillin?
Oral Amoxicillin
What route of Administration is NOT Recommended in C.Difficile Infection?
IV
This is because as C.Difficile is a gut pathogen, you need oral administration to coat the inside of the bowels.
What route of administration is recommended for mild infections?
Oral as not much drug is needed.
What route of administration is needed in severe infections e.g. Bacteraemia or Sepsis?
IV to take on the huge bacterial overload
What is the main antibiotic for gram negatives and how it is USUALLY administered?
Gentamicin
Once a day in a high dose to get in in the system quickly and out the system quickly to avoid renal toxicity.
Name sites which are difficult for Antibiotics to penetrate?
CNS, Eyes and Prostate (in Prostate, the type of antibiotic matters more than the route administered)
What route of administration is generally considered for areas that are difficult to penetrate with antibiotics?
High Doses with IV administration
What Antibiotic is used in severe C.Difficile Infection?
Is recurrence of C.Difficile infection possible?
Oral Vancomycin
Yes as C.Difficile forms spores
What aspect of the Gram Negative Bacterial structure drives Sepsis?
Liposaccharides
Which classes of antibiotics work against Gram Negative Bacteria?
Beta Lactams Monobactams Aminoglycosides Macrolides Tetracyclines Co-Trimoxazole
What are Monobactam antibiotics?
How do they work?
Monobactams are a subgroup of Beta Lactams with a slightly different chemical structure.
Binds to bacterial proteins to kill them (Bactericidal)
What are Monobactam antibiotics ineffective against?
Gram Positives and Anaerobes
They do not bind well to the proteins in these bacteria
Give an example of a Monobactam antibiotic
HINT: Think “-nam”
Aztreonam (only one in use currently)
What are Aminoglycoside antibiotics?
How do they work?
Antibiotics that consist of 2+ Amino Sugars.
Bind to Ribosomal Proteins to inhibit protein synthesis and accelerate cell death (Bactericidal)
What are Aminoglycoside antibiotics ineffective against?
Anaerobes
Give an example of an Aminoglycoside
HINT: Think “-cin”
Gentamicin
Amikacin
When is Gentamicin contraindicated?
What antibiotic can be used as an alternative?
In patients with Myasthenia Gravis or Renal Impairment (as it causes Renal Toxicity)
Aztreonam is used as an alternative
What are Macrolide antibiotics?
How do they work?
Naturally-derived antibiotics which consist of a large macrocyclic lactone ring.
Bind to a Subunit of the Bacterial Ribosome to inhibit Protein Synthesis (Bacteriostatic)
Give an example of a Macrolide
HINT: Think “-mycin”
Clarithromycin
Azithromycin
Erythromycin
Clindamycin
NOT VANCOMYCIN WHICH IS A GLYCOPEPTIDE ANTIBIOTIC
What are Tetracycline antibiotics?
How do they work?
Antibiotics with 4 Hydrocarbon Rings.
Inhibits the bacterial ribosomes, inhibiting protein synthesis (Bacteriostatic)
Give an example of a Tetracycline
HINT: Think “-cycline”
Doxycycline
Tetracycline
What are Quinolone antibiotics?
How do they work?
Antibiotics which all chemically consist of a bicyclic ring.
Inhibit protein synthesis (Bacteriostatic)
Note that Fluoroquinolones are a modern, modified subset of Quinolones.
Give an example of a Quinolone antibiotic
HINT: Think “-flocaxin”
Ciprofloxacin
Ofloxacin
Give examples of ESBL-producing bacteria
E.coli
Klebsiella
Which antibiotic does NOT work too well on E.coli in Tayside?
Amoxicillin, due to 40% resistance
What are Cephalosporin antibiotics?
How do they work?
Class of Beta Lactam Antibiotics!
Inhibit enzymes in the cell wall to cause bacterial cell death (Bactericidal)
Give an example of a cephalosporin
HINT: Think “-ime”
Ceftazidime
Cefixime
Which antibiotics are used to treat Strep. Pneumoniae infection in individuals who have returned from countries of high penicillin resistance?
Vancomycin with Rifampicin
Which form of Penicillin is no longer sensitive to Strep. Pneumoniae?
Penicillin G (Benzylpenicillin) Modified drug target means that it can no longer attach to strep. pneumoniae
Which antibiotics are used to treat H. Influenzae?
Amoxicillin
Doxycycline
In regards to the Enterococci, what antibiotic resistance do you need to be aware of?
Vancomycin-Resistant Enterococcus
What is Atypical Pneumonia?
Pneumonia that is NOT caused by the Streptococci species
What antibiotics can be used to treat Atypical Pneumonia?
Doxycycline
Clarithromycin
What antibiotic is used in Mild C.Difficile Infection?
How do you differentiate between a Mild and Severe C.Difficile infection?
Oral Metronidazole
WBC Count > 15 cells x 10^9
How is ESBL treated?
Gentamicin
If resistant, then IV Carbapenems e.g. Ertapenem, Meropenem etc.
What is used to treat Strep. Pneumoniae infection first line?
Penicillin
Which group of Antibiotics are used to treat CNS infections?
Penicillins, as they cross the Blood Brain Barrier
What bacteria does Clindamycin not cover?
Gram Negatives
What antibiotic is used in infection prophylaxis in HIV?
Co-trimoxazole
What are side effects of Gentamicin?
Nephrotoxicity
What are side effects of Vancomycin?
Red Man Syndrome
What are side effects of Macrolides?
GI Disturbances
What are side effects of Doxycycline?
Photosensitivity
What are side effects of Penicillins?
Rash/Hypersensitivity (most patient take this to mean allergy but it is not!)
What are GENERAL Side Effects of Antibiotics?
Nausea, Vomiting, Rash
What effect does Metronidazole have on Lithium?
Reduces Lithium concentration
What interactions does Rifampicin have?
Turns contact lenses orange and reduces Warfarin effect.
What are severe associations with Quinolones?
AAA
Psychiatric Disturbances
Diffuse Tendinitis or Tendon Rupture
Which antibiotic should NEVER use as Monotherapy?
Rifampicin
What kind of antibiotic should you use FIRST in infection?
The most narrow-spectrum antibiotic to that infection
What antibiotic is used in Surgical Prophylaxis?
How long should surgical prophylaxis be done for?
Co-amoxiclav
24 hours
What is the Reserve List?
List of antibiotics which are NOT RECOMMENED for use
