Anti-bacterial Drugs Flashcards
Which two super-infections are common ADRs of anti-bacterials?
C. albicans and C. difficile
What are the major targets of antibacterials?
Cell wall synthesis, protein synthesis, nucleic acid synthesis, microbial metabolism.
What are the three antibiotic groups that target cell wall synthesis?
Beta-lactams (penicillins, cepathosporins), glycopeptides (vancomycin), polypeptides (bacitracin)
What is the mechanism of action of beta-lactam antibiotics?
Prevent polymer cross-linking in the peptidoglycan cell wall, disrupting osmotic pressure and causing cell lysis.
What is the mechanism of action of clavulanic acid?
Beta-lactamase inhibitor, used with beta-lactams (amoxicillin) to overcome resistance to beta-lactams.
What are the two major types of beta-lactams?
Penicillins and cephalosporins
What is the ADR of cephalosporins?
Nephrotoxic
What is the ADR of penicillins?
Seizures at high doses
What is vancomycin (glycopeptide) used for?
MRSA - resistant severe Gram positive infections
What are ADRs of vancomycin (glycopeptide)?
Ototoxicity, hypersensitivity, nephrotoxocity.
What is the main route of administration for beta-lactam antibiotics?
Injections.
List four classes of antibiotics that interfere with protein synthesis.
Aminoglycosides, tetracyclines, macrolides, others.
What is the mechanism of action of aminoglycosides, such as gentamicin?
Irreversibly bind to 30S subunit of ribosomes.
What is gentamicin (aminoglycoside) used for?
Serious infections, usually blood-borne.
Is gentamicin (aminoglycoside) bacteriocidal or bacteriostatic?
Bacteriocidal at therapeutic doses.
What are the ADRs of gentamicin (aminoglycoside)?
Ototoxicity, nephrotoxicity, neuromuscular paralysis (in rapid IV)
What is the mechanism of action and activity spectrum of tetracyclines?
Reversibly bind to the 30S subunit of ribosomes, prevent tRNA action. Broad-spectrum.
What are the ADRs of tetracyclines?
Bind to free divalent and trivalent ions in blood, affecting oral absorption.
Vitamin B deficiency (not used in small children).
What is the mechanism of action of macrolides (erythromycin)?
Reversibly vinds to the 50S subunit of ribosomes, preventing movement along mRNA. Does not interact with the human ribosome.
Why can macrolides be used when penicillins cannot?
Similar spectrum of activity.
Name three non-macrolide antibiotics that bind to the 50S subunit of the ribosome to disrupt protein synthesis.
Lincosamides (lincomycin, clindamycin), chloramphenicol, fusidic acid.
What are ADRs of chloramphenicol?
Aplastic anaemia, cell toxicity.
What is chloramphenicol used for?
Eye drops, systemic in resistance.
List three groups of antibiotics that interfere with nucleic acid synthesis.
Fluroquinolones, nitromidazoles, rifamycins.
