Antimicrobials Flashcards
Which group of antibiotics cause yellowing of neonatal teeth?
Tetracyclines such as lymecycline
What is the mechanism of action for penicillins?
penicillins are beta-lactam antibiotics which inhibit petidoglycan cross-link formation in bacterial cell wall
What is the mechanism of action for cephalosporins?
beta-lactam antibiotics which inhibit petidoglycan cross-link formation in bacterial cell wall = bactericidal
Give examples of cephalosporins
cefuroxime, ceftriaxone, cefalexin
Give examples of penicillins
amoxicillin, phenoxymethylpenicillin, flucloxacillin
What is the mechanism of action for macrolides?
bacteriostatic antibiotics, inhibit protein synthesis, inhibit petidlytransferase, bind to 5oS ribosome
Give examples of macrolides
erythromycin, clarithromycin, azithromycin
Give examples of quinolones
ciprofloxacin, levofloxacin
What is the mechanism of action of quinolones
DNA gyrase inhibitor - stops DNA replication (ciprofloxacin and levofloxacin)
What is the mechanism of action of ciprofloxacin?
DNA gyrase inhibitor - stops DNA replication - bacteriostatic
What is the cross reactivity of cephalosporins and penicillins in pen allergic patients?
10%
Which drugs interfere with folate metabolism?
dihydrofolate reductase inhibitors (trimethoprima nd methotrexate)
Sulphonamide inhibiting benzoic acid to folate conversion by inhibiting dihydropteorate synthetase (glizazide/thiazide diuretics;furosemide)
Quinolones and breast feeding
should be avoided
Risk of aminoglycoside use in pregnancy
risk of 8th cranial nerve ototoxicity
Grey baby syndrome is caused by toxic levels of which anti-microbial?
Chloramphenicol - hypotension and cyanosis
Which sterol is found in the cell membranes of fungi but not humans?
Ergesterol
What is the main target of anti-fungal agents?
Ergesterol in fungi cell membranes
What is amphotericin B?
An antifungal that disrupts fungal cell membranes by binding to ergesterol
What is nystatin?
A polyene antifungal - inhibits ergesterol
What are fluconazole, clotrimazole and ketonazole?
imidazole antifungals - inihbit ergesterol synthesis - should not be used in pregnancy
Antibiotic prophylaxis in a patient who is chlamydia negative and has had an abortion
metronidazole 1g PR stat
What base is aciclovir an analogue of?
guanine
How does aciclovir work?
prodrug - converted to active form by thymidine kinase in viral cell to form guanine analogue - inhibits viral DNA polymerase
What activates aciclovir?
aciclovir is a prodrug acitvated by thymidine kinase in viral cells
What kind of antimicrobe is zidovudine?
nucleoside reverse transcriptase inhbitor - inhibits souble stranded DNA synthesis - used to treat HIV particularly in pregnancy as a monotherapy or in neonate for prophylaxis
Which anti-malarial chemo-prophylaxis is safe for use in pregnancy?
mefloquine (larium) or malerone
