Drugs that weaken cell walls: pencillins Flashcards
structure and function of penicillin
structure: beta lactam ring
function: active against a variety of bacteria- some resistance happens, and it can be widespread across all penicillins, or it can be individual subclasses
beta-lactam family includes (4)
1) Penicillin
2) cephalosporin
3) monobactam
4) carbapenem
Mechanism of action of penicillins
disrupts cell wall by binding to PENICILLIN-BINDING PROTEINS to weaken it and allow bacteria to take up excessive water and rupture (bactericidal
Three factors of resistance to penicillins
1) inability to reach the target PBP
2) inactivation by bacterial enzymes (beta-lactamases, penicillinases, cephalosporinases, that destroy the lactam ring)
3) production of PBPs with low affinity for beta-lactams
4 classes of penicillins
1) Narrow spectrum penicillins: penicillinase sensitive
2) Narrow spectrum penicillins: penicillinase resistant
3) Broad- spectrum penicillins
4) extended-spectrum penicillin (least likely to develop resistance)
Narrow spectrum penicillins- penicillinase sensitive
1) drugs
2) clinically useful antimicrobial spectrum
These are penicillinase sensitive
Example: Penicillin G and Penicillin V
- Used against streptococcus species (strep pharyngitis)
- Gram +, some Gram -, anaerobes, spirochetes
Narrow spectrum penicillins: penicillinase resistance
1) Drug Names
2) Uses
- these are used against STAPHYLOCOCCUS AUREUS, “antistaphylococcal”
- MSSA, Gram + and some Gram -
- example: Nafcillin, oxacillin, Dicloxacillin
NOD at STAFF (staph)
Broad Spectrum Penicillins
1) Drugs
2) antimicrobial spectrum
- These are aminopenicillins
1) amoxicillin
2) ampicillin - Example:
1) ampicillin (when combined with sulbactam= UNASYN)
2) amoxicillin (when combined with clavulanic acid = AUGMENTIN) - Gram +, Gram -, Anaerobes, Spirochetes
Extended spectrum penicillin
1) Drug
2) Antimicrobial spectrum
- these are anti-pseudomonal penicillins
- example:
1) piperacillin (combined with tazobactam = zosyn) - MSSA, Gram +, Gram -, Pseudomonas, anaerobes
(pneumonia or complicated cellulitis) - used when pseudomonas or other resistant gram negative bacteria is suspected or confirmed.
- Used for sepsis of unknown etiology
- no MRSA, VRE, or atypical coverage
Uses of penicillinase sensitive penicillins
1) Group a: pharyngitis
2) group b: OB
3) syphillis
MOST GRAM +, ANAEROBIC BACTERIA, SPIROCHETES, AND SOME GRAM -
- same as the anti-staphylococcal penicillins but without MSSA coverage
Black box warning for penicillinase sensitive penicillins
appropriate administration of IM ONLY
- IV administration has led to cardiorespiratory arrest and death
Routes of penicillinase sensitive penicillins
1) penicillin G sodium - iv or im
2) penicillin G BENZATHINE- long acting IM ONLY***
3) penicillin VK- oral
ADR of Pencillin
- allergic reactions- most common of all drug allergies
- pain at IV and IM injection sites
Uses for Antistaphylococcal Penicillins: Nafcillin, oxacilliln, dicloxacillin
- active against penicillinase producing strains of staphylococcus (MSSA) and some gram - coverage.
- anaerobes
- spirochete
- NO ACTIVITY against MRSA
- MSSA, Gram +, some Gram -, anaerobes, spirochetes
Routes of antistaphylococcal Penicillins: Nafcillin, oxacilliln, dicloxacillin
1) oral - dicloxavillin
2) IV- nafcillin, oxacillin
ADR antistaphylococcal Penicillins: Nafcillin, oxacillin, dicloxacillin
ADR: allergic reactions- most common of all drug allergies
Uses of aminopenicillins (amoxicillin and ampicillin). And something unique
- Same spectrum as penicillin + increased activity against GRAM (-) bacilli
- READILY INACTIVATED BY BETA-LACTAMASES- but still widely used and effected.
- watch for lack of clinical response**
- gram+, gram -, anaerobes, spirochetes
Routes of aminopenicillins (amoxicillin and ampicillin)
1) oral - amoxicillin, ampillicin (DON’T USE POOR ABSORPTION)
2) IV- Ampicillin
3) IV- Ampicillin/ sulbactam = UNASYN
- used for cellulitis with anaerobe involvement and aspiration pneumonia
ADRs for aminopenicillins (amoxicillin and ampicillin)
ADR: allergic reaction - most common of all drug allergies
What are the four beta lactamase inhibitors
1) clavulanic acid (clavulanate)
2) tazobactam
3) sulbactam
4) avibactam
think (CAST) ; when used with an antibiotic they extend microbial spectrum of activity
- they give activity back to the penicillinase or cephalosporinase sensitive bacteria
Three main drugs made with beta lactamase inhibitors
1) Unasyn - ampicillin/sulbactam
2) Augmentin- amoxicillin/clavulanic acid
3) Zosyn - peperacillin/ tazobactam
Uses of piperacillin/ tazobactam (zosyn)
- broad spectrum antibiotics used in a variety of infections - pneumonia, complicated cellulitis, osteomyelitis, sepsis of unknown etiology, catheter related infections
- covers MSSA (usually) pseudomonas and ANAEROBES
- PRIMARY USE: pseudomonas or other resistant GRAM - bacteria is suspected
-MSSA, gram +, gram -, anaerobes, pseudomonas
PNEUMONIA/ sepsis of unknown etiology/ CATHETER
what uses does piperacillin/ tazobactam (zosyn) lack?
Lacks MRSA, atypical bacteria, and VRE
Routes of piperacillin/ tazobactam (zosyn)
IV
ADR for piperacillin/ tazobactam (zosyn)
ADR: AKI- particularly in combination with other nephrotoxic drugs (vancomycin)
Unasyn
ampicillin and sulbactam
Augmentin
amoxicillin and clavulanic acid
