Penicillins Flashcards
Penicillin G
o X million units IVPB
o every 4 hours
In Hospital: 5 million units, followed by 2.5 million units
Group B strep
Penicillin G aqueous
o 18 to 24 million units IVPB
o per day total divided evenly every 4 hours or continuous infusion for 10-14 days
Neurosyphilis
Penicillin G Benzathine (Bicillin-LA®)
o 2.4 million units
o Intramuscularly once
Syphilis
Group A Strep pharyngitis
Penicillin V potassium
o 500 mg
o One tablet every 6 hours around the clock
Strep throat
For kids use mg/kg
What are the first generation antimicrobial agents for cell wall synthesis?
Penicillin G Penicillin G procaine Penicillin G benzathine Penicillin G benzathine and penicillin G procaine Penicillin V potassium
Are Penicillin G and Penicillin V Penicillinase resistant?
No, so bacteria can become resistant to the meds
How is Penicillin G’s oral absorption?
Variable (poor)
IV best
How is Penicillin V’a oral absorption?
Good, only in oral form
Are Ampicillin and Amoxicillin Penicillinase resistant?
No, so bacteria can become resistant to the meds
How is Ampicillin’s oral absorption?
Good
Can be IV too
How is Amoxicillin’s oral absorption?
Excellent (oral only)
What are the first generation penicillins primarily used for?
Syphilis Streptococcal pharyngitis Meningococcal infection Necrotizing Fasclitis Streptococcal endocarditis Pasturella multocida
What are the Broad spectrum antimicrobial agents for cell wall synthesis?
Ampicillin
Amoxicillin
Amoxicillin and clavulanate
What are the Broad spectrum antibiotics (ampicillin, amoxicillin) used for?
Upper respiratory infections
Active against S. pyogenes, S. pneumoniae, H. influenzae; sinusitis, otitis media, acute exacerbations of chronic bronchitis, epiglottitis
Amoxicillin
o 500 mg
o One capsule every 8 hours around the clock
Smaller person = 250 mg
Kid = 125 mg
*Kid can do mg/kg but NEVER exceed adult dose
Ampicillin/sulbactam (Unasyn®)
o 3 g IVPB
o every six (6) hours
For every 3 g you get:
2 g Ampicillin and 1 g Sulbactam
* So calculate for ampicillin *
(Sulbactam is B-Lactamase inhibitor)
What are the Antistaphylococcal antimicrobial agents for cell wall synthesis?
Nafcillin
Oxacillin
Dicloxacillin
Are Nafcillin and Dicloxacillin Penicillinase resistant?
Yes! so no bacterial resistance
How is Dicloxacillin’s oral absorption?
Good
How is Nafcillin’s oral absorption?
Variable (IV only)
What is Dicloxacillin good against?
Less effective against organisms sensitive to penicillin G
No gram-negative activity
Staph infections, MRSA
What is Nafcillin good against?
staphylococcal meningitis
MRSA
Nafcillin (Nallpen®)
o 1 or 2 g IVPB
o every four (4) hours
Can dose 3 g ever 6 hours
Prosthetic joint infection
Dicloxacillin
o 500 mg orally
o One capsule every six (6) hours
Can be 1 g ever 8 hours
No oral suspension for kids
What are the Extended Spectrum antimicrobial agents for cell wall synthesis?
Piperacillin
Piperacillin and tazobactam
Ticarcillin and clavulanate potassium
Is Piperacillin Penicillinase resistant?
No! so bacteria can be resistant
How is Piperacillin’s oral absorption?
Poor (IV only)
What are the Extended Spectrum antimicrobial agents for cell wall synthesis used for?
Pneumonias
Gram negative infections:
- Pseudomonas aeruginosa
- Proteus (indole-positive)
- Enterobacter spp.
Piperacillin/tazobactam (Zosyn®)
o 3.375 g IVPB
o every six (6) hours
Every 3.375 g get 3 g Piperacillin and 0.375 g tazobactam
2.25 g is lower dose
What are the Beta lactamase inhibitor combinations (BLICs)?
Oral:
Amoxicillin/clavulanate potassium (Augmentin™)
Injectable:
Ampicillin/sulbactam (Unasyn™)
Piperacillin/tazobactam (Zosyn
Worst offender of hypersensitivity reactions?
Ampicillin
What are possible hypersensitivity reactions to the penicillins?
Manifestation from most likely to least likely:
Maculopapular rash Urticarial rash Fever Bronchospasm Vasculitis Serum sickness Exfoliative dermatitis Stevens-Johnson syndrome Anaphylaxis
What are possible side effects due to the oral route of the penicillins?
Change in gastrointestinal microflora:
Most patients bounce back after therapy discontinued.
Superinfection
Pathological changes to the microflora
Clostridium difficile incidence?