Drugs but for realsies Flashcards
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7 common mechanisms of antibiotics
1) Disrupt bacterial cell wall
2) Increase permeability of cell membrane
3) lethal inhibition of bacterial protein synthesis
4) nonlethal inhibition of protein synthesis
5) Inhibit synthesis of nucleic acids
6) Antimetabolites
7) Inhibitors of viral DNA replication
B lactam antibiotics mechanism of action
Disrupt bacterial cell wall causing them to take up water and burst through inhibiting transpeptidases that catalyze cell wall formation and activation of autolysins that cleave bonds in wall by binding Penicillin binding proteins
Penicilins are inactive against most….
…gram negative bacteria
B-lactamases
Coded for by a plasmid between bacteria to promote synthesis of proteins that release into the space around them to cleave certain PCNs
Narrow spectrum PCN’s that are penicillinase sensitive
- PCN-G
- PCN-V
PCN-G treats what organisms, and is available in what form? Side effects?
Acts mostly on gram positive organisms, plus syphilus! Available in 4 diff salts depending on route of administration and course of action, Least toxic of all antibiotics, can have allergic reaction
If a patient has a PCN allergy, then how should we use cephalosporins?
Cautiously, probably avoid if severe PCN reaction
PCN drug interactions (3 to know)
1) probenecid - delay excretion
2) aminoglycosides - inhibed by PCNs and need to be administered separately
3) Bacteriostatic antibiotics - PCNs work best on fast dividing
PCN-V
Similar to Pen G but soluble in gastric acid so replaced pen G for oral therapy
Narrow spectrum PCN’s that are penicillinase resistant
- oxacillin
- dicloxacillin
Oxacillin and dicloxacillin treats what pathogens?
S. aureus and S. epidermidis
Broad spectrum aminopenicllins
- ampicillin
- amoxicillin
Ampicillin and amoxicillin treat what organisms? Side effects?
- gram positive plus some gram negative bacilli
- amoxicillin rash (not serious) in children
Anti pseudomonal penicillins
-Piperacillin
Cephalosporins mechanism of action
Same as PCN’s, bind PBP and disrupt cell wall snthesis and activate lysins
1st -5th gen cephalosporins
- 1st gen most susceptible to B lactamases, 5th is highly resistant
- Increased activity against gram - bacteria
- increased ability to reach csf
Cephalexin and what it treats
1st gen cephalospoirin, active against staphyloccoci and nonenterococcal streptococci, treat real easy shit sometimes given before surgery even
Cefoxitin
2nd gen cephalosporin, Increased activity against gram - bacteria
Ceftazidime and what it treats
3rd gen cephalosporin, broad spectrum, DOC for gram - bacilli
Cefipime
4th gen cephalosporin, highly resistant to B lactamases and broad spectrum of activity
Ceftaroline and what it treats
5th gen cephalosporin, only one active against MRSA
Cephalosporin absorption method, adverse side effects?
IM or IV required, allergic hypersensitivity, bleeding
Disulfuram like reaction
Occurs if patient is taking a cephalosporin and ingests alcohol
Don’t mix ceftriaxone and…
Ca2+, fatal precipitate
Carbapenems
B-lactam antibiotis that like penicillins and cephalosporins, inhibit bacterial cell wall synthesis, have very broad antimicrobial spectrum
Imipenum
Broad antimicrobial speectrum, can treat mixed infections
Carbapenems method of absorption
Paraenterally (IV)
Meropenum
Active against most gram pos and gram negative organisms
Vancomycin usage
Widely used for C. difficile infections, MRSA, and patients with PCN allergies
Vancomycin antimicrobial spectrum
Primarily gram + bacteria
Vancomycin adverse effects
- Renal failure (dose related)
- Ototoxicity
- Red man syndrome (histamine release resulting in rashes, flushing, potential to go into shock)
Alternatives to vancomycin
Teicoplanin (no bad side effects really)
Fosfomycin
Telavancin
Aminoglycosides are primarily effective against…
gram neg aerobes (must be aerobic for uptake)
Aminoglycoside mechanism of action
Disrupt bacterial protein synthesis by byinding the 30S ribosomal subunit, rapidly bacteriocidal
Aminoglycoside absorption, side effects
Paraenterally only (unless intended effect is to act in GI), sometimes topical therapy, ototoxicity nephrotoxicity, neuromuscular blockade
Neommycin, gentamicin
Topical aminoglycoside therapy
Aminoglycoside dosage must be very _____ because it has a _______
personalized, low therapeutic index
These two should never share an IV bag
PCNs and aminoglycosides
Gentamicin treats what organisms?
Treats serious infections caused by aerobic gram neg bacilli
Amikacin characteristics
- Broadest spectrum
- least vulnurable to inactivation
Tetracyclines mechanism of action
Broad spectrum antibiotics that inhibit protein synthesis at the ribosome after being transported via energy dependent processes
Tetracycline is rarely first drug of choice due to resistance in common bacterial diseases, but are still used to treat these few.
- Rickettsial diseases
- Chlamydia trachomatis
- Brucella
- Cholera
- Mycoplasma pneumoniae
- borelia burgdorferi
- H pylori
- antrahx
- acne vulgaris
Tetracycline absorption
Not bad absorption via GI, but form insoluble chelates with cations preventing absorption and thus require administration 1-2 hours after ingestion of a chelate
Tetracycline side effect
- GI upset
- bones and teeth coloraion
- suprainfection
- hepatotoxicity
- photosensitivity
Longest acting tetracycline
Doxycycline
Macrolides mechanism of action
Broad spectrum antibiotics that act by inhibiting bacterial protein synthesis, bind 50S ribosome and are bacteriostatic
Erythromycin spectrum
Similar to penicillin, active against most gram positive, some gram neg
When should erythromycin be used as DOC
Bordatella pertussis, corynebacterium diptheriae
Erythromycin absorption
Food decreases absorption
Erythromycin side effects
GI disturbances, QT prolongation and sudden cardiac death
Clarithromycin
2-4x more active than erythromycin,
Azithromycin
-More potent against specific organisms
Chloramphenicol
Broad spectrum antibiotic with severe risk of causing aplastic anemia
Chloramphenicol is drug of choice for…
Typhoid fever, bacterial meningitis
Gray baby syndrome
Neonates who have been given large doses of chloramphenicol
Dalflopristin/quinipristin, linezolid, treats
VRE
Fluoroquinolones
Broad spectrum PO
Fluoroquinolones side effects
Tendon rupture, peripheral neuropathy,
Cirpofloxacin
takes care of a lot of shit
Fluorquinolones mechanism of action
Passive diffusion, inhibit DNA replication, rapidly bactericidal
Ciprofloxin warfarin interaction
Elevates levels
Metronidazole
Useful for porotozoal infections and obligate anaerobic bacteria
Rifampin side effects
Discolored body fluids
