Lecture 7: Penicillins Flashcards
Erdman's Section
How is the MOA similar among all B-lactams?
- ALL inhibit cell wall synthesis & PBPs
- Inhibition of PBP = failed cell wall synthesis = lysis & death
How is the Mechanism or Resistance similar among all B-lactams?
- Destoryed by B-lactamases
- Alteration of PBP [MRSA & PRSP]
- Decreased permeability of Gram (-) [Altered Porins]
How are the Pharmacodynamics similar among B-lactams?
- T>MIC
How is the Elimination similar among all B-lactams?
- Short half time [>2 hours]
- Except Ceftriaxone, Cefotetan, Cefixime, Ertapenem
How is Renal Elimination similar among all B-lactams?
- Unchaged by Glomerular Filration and Tubular Secretion
- Except Nafcillin, Oxacillin, Ceftriaxone, Cefoperazone
How is Cross-Allergenicity similar among all B-lactams?
- ALL except Aztreonam
What is the reason that Penicilins are Bactericidal?
- Inhibit PBP = Failed Cell Wall Synthesis = Lysis & death
- ONLY Bacteriostatic to Entercoccus
What are some of the “Bugs” that produce the b-lactamase?
- Gram (+): Only S. Aureus
- Gram (-): Aerobes & Anarobes
What are the Different Classes of Penicillins?
- Natural Penicillins
- Antistaphyococcal Penicillins
- Aminopenicillins
- Carboxypenicillins
- Urediopenicillins
- Combos
What are the Natural Penicillins?
- Penicillin G [IV]
- Benzathine Penicllin [IM]
- Procaine Penicillin [IM]
- Penicillin VK [Oral]
What is the spectrum of activity for the Natural penicillins?
- Gram (+): Group/Virdian Strep, Most Enterococci
- Gram (-): COCCI; Neisseria sp
- Anaerobes: ATD & BTD
- Trepnema Pallidum [DOC of Syphilis]
What is one “Bug” that Natural Penicillins do NOT cover?
- Staphylococcsus
What is Penicillin G still considered Drug of Choice?
- Group/Virdian Strep
- Niesseria Meningitidis
- Corynebacterium Diphtheriae
- Bacillus Anthracis [Anthrax]
- Clostridium Prefringens/Tetani
- Treponema Pallidum [Syphilis]
What are the Antistaphylococcal Penicillins?
- Nafcillin, Methicillin, Dicloxacillin
When a patient has “MRSA”, what does that mean for the rest of the class?
- Resistant to all drugs within the class
- BUT susecptable to all too is MSSA
What is the spectrum of activity for Antistaphylococcal Penicillins?
- Gram (+): Group/Virdian Strep, MSSA [NOT MRSA]
- Gram (-): Nothing
- Anaerobes: Nothing
What are the Aminopenicillins that are used?
- Ampicillin, Amoxicillin
What is the spectrum of activity for Aminopenicillins?
- Gram (+): Group/Viridan Strep, Entercoccus Sp., Listeria Monocytogenes
- Gram (-): Salmonells/Shigella, H. Influenzae, E. Coli, P. Mirabilis
“SHEP”
What is Ampicillin/Amoxicillin the Drug of Choice for?
- Entercoccus sp.
- Listeria Moncytogenes
What are the Carboxypenicillins used?
- Ticarcillin
What is the spectrum of activity toward the Carboxypenicillins?
- Gram (+): WEAK activity to Strep
- Gram (-): Salmonella/Shigella, H. Influenzae, E. Coli, P. Mirabilis, Morgenlla Sp., Enterbacter Sp., Providenca Sp., Pseudomonas Aeruginosa
“SHEPMEPP”
What are the Carboxypencillins NOT active against?
- Klebsiella sp., Serratia sp.
What are the Ureidopenicillins that are used?
- Pipericillin
Has acyl chain = increases in cell wall penetration
What is the spectrum of activity for the Ureidopenicillins?
Gram (+), Gram (-), Anaerobes
- Gram (+): Group/Viridan Strep
- Gram (-): Mostly Enterbacterales, S. Marcescens, Klebsiella sp., Pseduomonas Aeruginosa
- Anaerobes: Bacteroides Fragilis
What is important to know about how the B-lactamase inhibitors work?
- Irreversibly bind to the catalytics site of the B-lactamase; inhibiting hydrolysis
What are the B-lactamase Inhibitor Combinations that are used?
- Amoxicillin/Clavulanic [Augmentin] PO
- Ampicillin/Sulbactam [Unasyn] IV
- Ticarcillin/Clavulanic [Timentin] IV
- Pipercillin/Tazobactam [Zosyn] IV
What is the spectrum of activity for B-lactamase Inhibitor combinations?
- Gram (+): MSSA; not primary antistaph
- Gram (-): Those with B-lactamase [E. Coli, Proteus sp., Klebsiella sp., H. Influenzae, M. Catarhalis, N. Gonorrhoeae]
- Anaerobes: Baceroides Fragilis
What are the important Pharmacodynamic Principles of Penicillins?
- T>MIC
- Bactericidal but are ONLY Bacteriostatic to Enterococcus
What is important to know about the absorption of Pencillins?
- Gedraded by gastric acid = not good for oral use; MUST do parenteral
What are some of the speacial considerations for Absorption in Penicillins?
- Natural: Pen G bad orally = Use Pen VK; Benz/Proc IM [depo]
- Amino: Amox more bioavailable than Ampi
- Antistaph: Dicloxcillin best bioavailability
What is important to know about the distribution of Penicillins?
- Into body tissues and fliuds [i.e.: pleural, synovial, bone, bile, placenta, pericardial
- NOT into eye or prostate tho
Where is one place that the concentrations of Penicillins are not good at?
- CSF; they are ONLY good when HIGH DOSES are used
What is the way that the Penicillins are eliminated?
- KIDNEYS by Glomerular Secretion and Tubular Secretion
- EXCEPT Nafcillin, Oxacillin, Pipericillin becases they are eliminated by the liver
SHORT HALF LIFE < 2 HOURS
Which Penicillins are removed via Hemodialysis?
- ALL except Nafcillin and Oxacillin
What are some other important Pharmacologic considerations to know about the Pencillins?
- SODIUM LOAD; will affect patients that have Heart Failure or Renal Dysfunction
- Pen G = 2.0 mEq
- Nafcillin = 2.9 mEq
- Ticarcillin = 5.2 mEq
- Piperacillin = 1.85 mEq
What are the Clinical Uses for the Natural Penicillins?
- Serious Infections = Pen G
- Mild to Mod Infections = Pen VK
- Strep Pneumoniae
- Group/Viridan Strep [IM Benz/ PO or IM]
- Endocarditis [IV with AG]
- Treponema Pallidum [THE DOC]
What are some of the clinical uses for Antistaphylococcal Penicillins/
- Infection do to MSSA; skin soft tissue, endocarditis… [Nafcillin]
- Oral Dicloxacillin for Mild to Mod
What are the clinical uses for the Aminopenicillins?
- Respiratory Tract Pathogens
- Parenteral for Enterococcal & Listeria Monocytogenes
- Endocarditis Prophylaxis
- Salmonella [Amox] & Shigella [Ampi]
What are some of the Clinical Uses for Carboxypenicillins and Ureidopenicillins?
- Piperacillin is the MOST active against Pseudomonas Aeruginosa
- Used as empiric
What are the Adverse Effects for the Penicillins?
- Hypersensitivity [Rash, Itching, Hives, Hypotension, Shock, Anaphylaxis]
- Neurologic: for those that get a HIGH DOES without renal adjustment
- GI [N, V, D; C.Diff]
- Interstitial Nephritis: acts as Hapten then damages kidneys [most common with Methicillin]
