Antibiotics Flashcards
beta lactams examples
Penicillins
Cephalosporins
beta lactams mechanism
Interfere with the synthesis of the bacterial cell wall peptidoglycan
Generally bactericidal
penicillins examples
Amoxicillin (broad spectrum)
Flucloxacillin (beta lactamase resistant)
Co-amoxiclav (amoxicillin with Clavulanic acid, beta lactamase inhibitor)
Phenoxymethylpenicillin (penicillin V)
penicillin application
Bacterial meningitis Bone and joint infections Skin and soft tissue infections Otits media Pneumonia UTIs STIs Individual sensitivity testing
cephalosporins
Cefalexin
Ceftriaxone
cephalosporin application
Septicaemia Pneumonia Meningitis Biliary tract infections UTIs (especially in pregnancy or in patients unresponsive to other drugs) Sinusitis Individual sensitivity testing
Antibacterials affecting bacterial protein synthesis
Tetracyclines
Aminoglycosides
Macrolides
Nitrofurans
Tetracyclines mechanism
uptake into susceptible organisms by active transport
act by inhibiting protein synthesis
Bind to bacterial ribosomes, preventing binding of tRNA to it
tetracyclines example, usage
Doxycycline, Tetracycline Bacteriostatic Respiratory tract infections (particularly atypical organisms) Acne Chlamydia Lyme disease Individual sensitivity testing Shouldn’t be given to children <12 years, pregnant and breastfeeding women (causes staining of developing teeth)
macrolides mechanism
Inhibit bacterial protein synthesis by an effect on ribosomal translocation Bactericidal/bacteriostatic
macrolides examples,
Clarithromycin
Erythromycin
Azithromycin
macrolides indication
atypical respiratory pathogens like penicillin: Bacterial meningitis Bone and joint infections Skin and soft tissue infections Otits media Pneumonia UTIs STIs Individual sensitivity testing
nitrofurans mechanism
reduced to multiple reactive intermediates by nitrofuran reductase inside the bacterial cell
attack ribosomal and DNA proteins within the bacteria,
inhibit the Citric acid cycle
nitrofurans example, indication
nitrofurantoin
excreted in the urine in unchanged form concentrate within urine, leading to more
effective levels within the bladder than in other tissue compartments
for UTIs
Quinolones mechanism
inhibition of DNA replication
quinolones examples, indication
Ciprofloxacin Complicated UTIs Pseudomonas aeruginosa cover Gonorrhoea good cover of Gram negative organisms, as well as atypical organisms and Gram positives
quinolones #
Tendinitis +/- rupture
Aortic dissection
Central nervous system effects (inc. Convulsions)
Antibacterial Agents That Interfere With Folate Synthesis or Action
Trimethoprim
Reversible inhibitor of dihydrofolate reductase
Bacteriostatic/bactericidal Clinical applications:
UTIs (careful when prescribing to reproductive age females)
metronidazole indication
antiprotozoal agent
good against: anaerobic bacteria
blocking nucleic acidsynthesis
Has disulfiram-like action, so patients must avoid using alcohol when on the antibiotic
antivirals
Aciclovir (DNA Polymerase Inhibitors)
Oseltamivir (Neuraminidase Inhibitors)
Aciclovir mechanism
activated in infected cells,
inhibits viral DNA polymerase
Aciclovir indication
Herpes simplex infections (genital herpes, encephalitis)
Varicella zoster (chicken pox, shingles)
CYP450 enzymes
most tissues of the body, but predominantly the liver
metabolism of many medications and hormones
CYP450 enzymes inhbitors
Inhibitors block the metabolic activity of one or more CYP450 enzymes
This means the drugs usually broken down by the inhibited enzyme will be
metabolised at a slower rate, essentially leading to an ‘overdose’
CYP450 enzymes Inducers
Inducers increase the enzyme synthesis of one or more CYP450 enzymes
This means more enzyme, therefore the drugs broken down by said enzyme break
down quicker, leading to below therapeutic levels in the blood
