Antibiotics Flashcards
Name two bacteriocidal and bacteriostatic types of antibiotics.
Bactericidal - cell wall synthesis inhibitors and inhibition of crucial enzymes
Bacteriostatic - protein synthesis inhibition
Name two antibiotics that interfere with folate synthesis.
Give the difference in their mechanisms of action.
Name a combined one.
Sulfonamides (sulfamethoxazole and sulfasalazine)
Trimethoprim
Sulfonamides (PABA analogues) - antagonise PABA at dihydropteroate synthetase
Trimethoprim - folate antagonist at DHFR
Co-trimoxazole
(Sulfamethoxazole and trimethoprim)
Give two ADRs of trimethoprim.
Give two ADRs of sulfonamides.
Folate deficiency (megaloblastic anaemia) Rashes/ N/V
Hypersensitivity (Steven’s Johnson’s syndrome/ toxic epidermal necrolysis)
Bone marrow supression
Renal failure
Name four groups of B-lactam antibiotics.
Name two B-lactam inhibitors.
Name some side effects.
Penicillins
Cephalosporins
Carbapenems
Monobactams
Tazobactam
Clavulonic acid
N/V diarrhoea
Hypersensitivity (rash -> anaphylaxis)
C diff infection
Convulsions (intrathecal admin)
Other than B lactams name another type of cell wall synthesis inhibitor.
Vanc - mainly against what?
Unwanted effects.
Name a monobactam.
Vancomycin and teicoplanin (glycopeptides)
Gram positives
Fever Rash Phlebitis Ototoxicity Nephrotoxicity Hypersensitivtiy
Aztreonam
Name two polymixins.
Mechanism of action.
Mainly active against?
Why are they used topically and for gut sterilisation?
Give two side effects.
Polymixin B
Colistimethate
Cationic detergent properties resulting in disruption to the outer cell membrane.
Gram negative bacilli (pseudomonads and coliforms)
Because they are not absorbed at all from the GIT.
Neurotoxicity
Nephrotoxicity
Name three macrolides.
Name a broad spectrum antibiotic that inhibits protein synthesis.
Why should tetracyclines not be given to pregnant people or children?
ADRs of tetracyclines.
Azithromycin
Erythromycin
Clarithromycin
Tetracyclines (doxycycline)
Because they chelate Ca2+ and therefore can be deposited in bone and teeth causing staging, dental hypoplasia and bone deformities.
GI disturbance.
Vitamin B deficiency
Aminoglycosides.
Mainly active against?
Two main side effects.
Macrolides.
MOA.
Gram negatives with some gram positives.
Ototoxicity and Nephrotoxicity.
Macrolides bind to 50S subunit
T/A - 30S subunit
MOA quinolones.
MOA metronidazole.
Why should it be avoided with alcohol?
Topoisomerase II inhibition (DNA gyrase)
Disruption of DNA in microbial cells
Disulfiram like action.
TB drugs.
Rifampicin MOA.
Which TB drug inhibits and induces CYPs.
Which three are associated with hepatotoxicity? Orange secretions? Visual? Gout? Agranulocytosis?
Inhibition of mycobacterial RNA polymerase.
Rifampicin induces
Isoniazid inhibits.
RIP R E P I
Distinguish between MIC and MBC.
Concentration dependant killing ABx use what parameter.
Time dependant killing ABx use what parameter?
What is the other parameter?
MIC - minimum concentration in which bacteria will not grow
MBC - minimum concentration in whilst bacteria are killed (Bactericidal)
CMax: MIC
T > MIC
AUC: MIC ration
Name 2 Abx that need TDM.
What is a pan-resistant microbe?
Aminoglycosides - due to nephrotoxicity and ototoxicity
Vancomycin - narrow therapeutic window
Not susceptible to all drugs in all groups a
DDIs.
Macrolide CYP effects?
Another ABx that inhibits.
Doxycyline and statin vs Macrolides and statins.
Inhibition of CYP2D6 and 3A4
Doxycyline.
Doxycyline + statins - hepatotoxicity
Macrolides + statins = myalgia, GI upset and headaches
