Penicillins Flashcards
Penicillin G administration
P, O
Pen V (Phenoxymethyl penicillin) administration
O
Phenoxyethyl Penicillin administration
O
Half life of Natural Penicillins
</= 1 hr (except in renal failure… could be up to 5 hours)
What does the repository forms of penicillins IM (e.g. procain pen G, benzathine pen G) change?
Makes the half-life of Pen much longer.
T1/2 of procaine pen G= 6-8hrs, benzathine pen G= 6 days
Antistaphylococcal penicillin half-life
All 0.5 hours in serum
>not changed significantly in renal failure (except Methicillin) b/c largely met/excreted by liver
Antistaphylococcal pen dosage must be changed in what circumstance?
Hepatic failure, esp for Nafcillin
Exception is methicillin (mostly renal)
Oral antistaphylococcal penicillins
CLOXacillin
diCLOXacillin
Antistaph penicillins taken P, O
Nafcillin
Oxacillin
Parenteral only Antistaph penicillins
Methicillin
Extended range penicillins
Ampicillin
Amoxicillin
Piperacillin
Ticarcillin
T1/2 for extended range penicillins
~1hr
What factor changes clearance of extended range penicillins?
Renal failure. Can be up to 10-15 hrs.
Except Piperacillin, which has some liver clearance
Parenteral only extended range penicillins
Piperacillin
Ticarcillin
Oral only extended range penicillin
Amoxicillin
P, O extended range penicillin
Ampicillin
Antistaphylococcal penicillins (Penicillinase-resistant)
Methicillin Oxacillin Nafcillin Cloxacillin Dicloxacillin
Penicillins that have best % absorption
Amoxicillin & Pen V
All penicillins are metabolized to varying degree by _______ and all get into _______ in good concentrations
All penicillins are metabolized by LIVER and all get into BILE in good concentrations
All penicillins (except Nafcillin) are chiefly eliminated by what structure?
Kidney–primarily by tubular secretion
This drug can inhibit tubular secretion to inhibit penicillin elimination
Probenecid
Penicillin distribution
- Wide but not in Prostate, CNS, or Eye,
- Inactivated in Abscesses
Penicillin is the DOC for…
- Strptococcal infections: GAS (pharyngitis, cellulitis); Strep pneumo (pneumonia, meningitis); E. faecoalis (w/ aminoglycosides)
- Some Non-Penicillinase-producing Staph aureus infxns
- Many non-Bacteroides anaerobes
- N. meningitidis
- Syphilis (treponemes)
Ticarcillin & Piperacillin notable coverage
Pseudomonas, Bacteroides
Community-acquired infections involving respiratory tract (OM, sinusitis, pneumonia, bronchitis) often treated with…
Ampicillin, Amoxicillin
Serious infections due to Gram - organisms usually treated with …
IV Ticarcillin, Piperacillin
w/ aminoglycosides
Extended range penicillins have synergistic activity with aminoglycosides against which two organisms in particular?
Enterococcus faecalis
Pseudomonas
IgE to MDM causes what reaction?
Anaphylaxis
IgE to BPO causes what reaction?
urticaria, rashes, angioedema
IgG and IgM cause what reaction?
Serum sickness, common rashes
Penicillin General Adverse Reactions
- Allergic reaction
- GI: Diarrhea, pseudomemb colitis
- Neuromuscular irritability: seizures (in high dose or renal failure)
- Hematologic: neutropenia, anemia
- Drug fever
- Interstitial nephritis
Ampicillin/Amoxicillin Reactions
Skin rash
Diarrhea
Pseudomemb colitis (C. diff)
Methicilin adverse reaction
Interstitial nephritis
Nafcillin adverse reaction
Phlebitis
Neutropenia
Oxacillin adverse reaction
Elevated hepatic transaminases
Neutropenia
Penicillin-Procaine adverse reactions
Neurologic reactions/abnormal behavior w/ high doses
Beta-lactamase inhibitors add activity against what organisms in particular?
- B-lactamase producing S. aureus
- B-lactamase producing H. flu
- Bacteroides
- Moraxella catarrhalis
Tx for mixed aerobic/anaerobic organism coverage where high-resistance strains (e.g. pseudomonas, enterobacter) are not suspected
Parenteral Ampicillin/Sulbactam
E.g. for GI/GU tract surgical infectiona dn pneumonias
Tx for upper and lower respiratory infections (OM, sinusitis, bronchitis) where b-lactamase producing H. flu or Moraxella are expected
Amoxicillin/Clavulanic Acid
“shotgun therapy” in seriously ill patients pending definitive identification of infecting organism(s).
Ticarcillin/Clavulanic Acid or
Piperacillin/Tazobactam
»may be used w/ aminoglycoside for enhanced spectrum and synergy