antibiotics Flashcards
Penicillin is a….
beta lactam
cephalosporins are…
beta lactams
carbapenems are…
beta lactams
What is the mechanism of action of Penicillins?
Cell wall disruption in actively dividing cells
What types of organism are sensivitive to penicillins?
gram +ve cocci - Streptococcus
Gram -ve cocci/bacilli - Listeria
Spirochetes - Syphilis
Co-amoxiclav contains which additional agent? Why
Clauvulanic acid, this prevents the action of beta lactamases produced by resistant microbes.
Also used in staph infecions
What are the general uses of Penicilins?
Broad: RTI’s. UTI’s, Skin and ear infections
Name the potential side-effects of penicillin use…
hypersensitivity:
In 10 % (0.2% anaphylaxis)
Diarrhoea
Cephadrine and Cephalexin have uses in what sort of conditions?
These 1st generation cephalosporins are used skin/soft tissue infection
Cefuroxime is used to treat what?
This 2nd generation cephalosporin is used in C.A. Pneumonia
Cefotaxime and ceftriaxone are used in what?
3rd Gen Cephs, these are for meningitis and pseudomonas
Name 2 macrolides
Erythromycin Clarithromycin
Note the -romycin suffix
how do macrolides work?
they inhibit protein synthesis
What is the side effect profile of Macrolides as a group?
Inhibit liver metabolism of warfarin and statins - may induce OD D and V Liver dysfunction Arrythmias
Name 2 Quinolones
Ciproflaxicin, Levofloxacin
How do quinolones work?
inhibition of DNA coiling
What is the spectrum of the quinolones group?
Generally broad spectrum, although second line
-only effective oral treatment for pseudomonas (as a group)
What can inhibit ciprofloxacin?
Metals
What are the contraindications for use of Ciprofloxacin and Levofloxacin?
Epilepsy - reduced fever threshold
Children
With which anticoagulant can quinolones interact?
Warfarin - can potentiate it’s effects
Name 2 tetracyclines
Doxycycline Oxytetracycline
How do tetracyclines work?
inhibition of protein synthesis
What are tetracyclines used to treat?
Skin and soft tissue infection
Acne
What are the contraindications to tetracycline use?
Children
Breastfeeding women
Pregancy
Can be incorporated into bones and teeth causing discolouration and growth stunting
Name a side effect of tetracycline use
photosensitivity
Name 3 aminoglycosides
Gentamicin Tobramycin and Amikacin
How do aminoglycosides work?
enter via 02 dependent transport system and inhibit protein synthesis
.: no action vs. anaerobes
What are aminoglycosides used in? how are they administered?
RTI and TB
I.V
What are the side effects of aminoglycoside use?
Ototoxicity especially in the elderly
Nephrotoxicity
What is the mechanism of action of trimethoprim?
Inhibition of folate production
How does metronidazole work?
it causes DNA damage
Against what sort of organisms is metronidazole effective?
Where might such infections occur?
Anaerobes
Abdo, perineal, GI
What are the side effects of Metronidazole?
Vomiting, tachycardia and dyspnoea if taken with alcohol
Rash and metallic taste
How does Rifampicin work?
It inhibits RNA production
Name a disease that Rifampicin is used to treat…
TB
in conjunction with isoniazid and pyrazinamide
Side effects and interactions of Rifampacin include….
P450 induction
increased metabolism of P450 metabolised drugs
Thromboembolism risk in warfarin
Stains contact lenses orange
Isoniazid is used in…..
TB combination therapy
Give an example of 2 glycopeptides….
Vancomycin teicoplanin
How do glycopeptides work?
inhibit cell wall production and damage cytoplasm
What diseases can be treated with Vancomycin
MRSA
resistant C.Diff
How is vancomycin administered?
I.V.
What is the side effect profile of Vancomycin?
Ototoxicity
Nephtotoxicity
Red man syndrome
What is red man syndrome?
An infusion reaction consisting of, flushing and/or erythematous rash affecting the face, neck and upper torso due to non-specific mast cell degranulation.
Hypotension and angioedema may also occur.
