The penicillins Flashcards
Name 7 essential penicillins
Penacilin G
Aminopenicillins
Anti-staph penacillis (Nafcillin)
Anti-pseudomonal penicillins (piperacilin)
Penicillin combinations with beta lactamase inhibitors
- Amoxicillin/clavulate (Augmentin)
- Ampeicillin/sulbacteam (Ubasyn)
Pipracillin/tazobactam (zosyn)
Cell wall synethesuis dsrupters (7)
Cycloserine Vancomycin/teichoplanin Bacitracin Penicillins Cephalosporins Monobactams Carbapenems
Where are beta lactamase inhibotors located
Periplasmic space
A ring
Penacilin made up of 2 rings
A ring: 4 carbons, carboxyl group & sulfer
B ring
4 carbons in the ring Amide bond (Amio group & carboxyl group)
Amide group in ring B can be destroyed by ring
Lactamase
Beside the amide bond name other location on penacllin molecule that can be disrupted
6th carbon amine group
Penacilin mechanism of action
Inhibit cell wall sythesis by disrupting mechanism of action of penicillin binding proteins
Beta lactam mechanism of action
analogs of the natural D-Ala-D-Ala substrate, and bind covalently to the PBP’s at the active site, thereby blocking the enzyme
Penicillin G Potassium Salt
Indications
Sensitive Bacteria
Resistant bacterial
Dosage
Interactions
SE/Toxicity
Indications
- Step. phyrangitis
- Skin infections
- Pneumonia
- Meningitis
- Endocarditis
- Dental infections
- Rheumatic fever
Sensitive Bacteria
- Strep
- Enterococcus
- Oral anerobes
- Menigoccus
- Syphilis
Resistant bacterial
- Most staph
- 30% pneumoccus
- GN
- Bowel anearobes
Dosage
- IV or IM
- Poor oral bioavability
- Renal excretion
Interactions
- Synergy: Gentamicin (cover staoh & enterocous)
- Bad: Probenecid inhibits renal active tubulor secretion
SE/Toxicity
Allergy, anemia, & seizures with high dose
Ampicillin
Indications
Sensitive Bacteria
Resistant bacterial
Dosage
Interactions
SE/Toxicity
Indications
- otis media
- Neonatal sepsis
- Lyme disease (rarely)
- UTIs
- Menegitis
- URI
- Endocarditis
- H. infuenza
Sensitive Bacteria
- streptococci, enterococcus, oral anaerobes,Listeria, and some GNRs
Resistant bacterial
- most staph, some pneumococcus (>30%), some H. flu, bowel anaerobes
Dosage
- PO or oral (40% bioavalable)
Interactions
Syndergy: Gentamicin
Bad: Prpbenicid
SE/Toxicity
- Celluitis, allergu, seizures at high doses
Nafcillin
Indications
Mechanism
Sensitive Bacteria
Resistant bacterial
Dosage
Interactions
SE/Toxicity
Indications
- S. areus infection
Mechanism
- Binds PBPs
Sensitive Bacteria
- Staph aureus (MSSA), some species of pneumococcus and streptococci
Resistant bacterial
- Staph aureus (MRSA), some species of pneumococcus, oral and bowel anaerobes, most GNR
Dosage
- IV only
- Hepatic metabollis
- Urine excretion
Interactions
Good: Gentamicin
Bad:: Probenecid & might inhibit methotrxate excretion
SE/Toxicity
- Allergy, antibiotic associated collitis
PIPERACILLIN
Indications
Mechanism
Sensitive Bacteria
Resistant bacterial
Dosage
Interactions
SE/Toxicity
Indications
- Pseudomonal infections
- Nosocomial pneumoniacaused by GNR in ICU
Mechanism
- Binds PBPs
Sensitive Bacteria
- streptococci,some enterococcus, many anaerobes, most GNRs including most pseudomonas
Resistant bacterial
- some pneumococcus, most Staph aureus, increasing resistant GNRs
Dosage
- IV only
- Renal clearance
Interactions
Good: Pseudomonas infections (usually given with gent or tobramycin for synergy
Bad: Probenecid & might inhibit methotrxate excretion
SE/Toxicity
Oral version of Pen G
Pen V
Penacillin that can be used oral or IV
Ampicilin
Oral version of anti-staph nafcillin
Dicloxacillin
Oral version of anti-pseudomonal peiperacillin
Carbenicillin
Augmentin
Dosing
Combination
Coverafe/Use
Oral amoxicillin plus clavulanic acid
Extends activity of amoxicillin to pathogens using this enzyme (e.g. B catarrhalis, H influenza, N gonorrhoeae, S aureus)
Used in otitis media, sinusitis, lung, skin, urine infections, bites
Unasyn
Dosing
Combination
Coverafe/Use
IV ampicillin plus sulbactam
Extends activity of ampicillin to pathogens using this enzyme (e.g S aureus, H influenza, E coli, Klebsiella, bowel anaerobes)
Used for skin, intra-abdominal, pelvic, bite, head/neck infections
Zosyn
Dosing
Combination
Coverafe/Use
IV piperacillin plus tazobactam
Extends activity to pathogens using this enzyme (e.g. S aureus, H influenza, Bacteroides, other GNR)
Used for pneumonia, UTI, skin, gyn, bone, intra-abdominal, septicemia infections
Why is penicillin given frequently
Very short half life
How is structure of of cephalosporin, monobactem and carbapenem different from penacillin
Cephalosporin
- A ring has 6 instead of 5 rings
Monobactem
- Absent A ring
Carbapenem
- A ring has 3 carbons
What is a beta lactame
All contain Ring A (thiazolidine ring) attached to Ring B (beta-lactam ring)
The beta-lactam ring always has a secondary amine at the corner, with an –R group attached
The beta-lactam ring is essential for activity
If the beta-lactam ring is cleaved, then the product (penicilloic acid) lacks antibacterial activity
What unit is penacillins ordered in
Ordered/measured in units (or million units) for Pen G only; mg for all others!!(As near as we can tell, this is part of a nasty plot by the NBME to torture medical students in Year 2 micro courses.)
H. influenza
Ampicillin
Major side effecto of methicillin?
- When was it used
- Better alternative
Methacillin - nephrotoxicity
Used for anti-staph
IV - Nafcillin
Oral - Dicloxacillin
S. areus
IV
Oral
Nafcillin - IV only
Dicloxacillin - PO
Only oral penicillin/beta-lactamase inhibitors
Augmentin amoxicillin plus clavulanic acid
Cat & dog bites oral treatment
amoxicillin
Penicillin for gram - coverage
Ampicilin or amoxicillin (causes less GI upset & fungal infections) so used for UTI
Gram - coverage but only IV
Piperacillin dose
Gram - coverage but only IV
Benefit of penacillin G over V
Penicillin G benzathine suspensin - IM in muscle over a month
V or G orally given 4 times a fay PO
