Penicillins Flashcards
Penicillins MOA
Bind to PBP resulting in inhibition of peptidoglycan synthesis and activation of autolytic enzymes in cell wall
Penicillin (Bacteriostatic or Bactericidal)
Bactericidal
How does penicillin resistance mainly develop?
- Production of beta-lactmases
- Lack of PBP’s or altered PBP’s
What organisms produce beta-lactamase enzymes?
- Staph
- Haemophilus
- Gram Negatives
What structure do all penicillins share?
- All penicillins share the same basic structure – 6-aminopenicillanic acid (thiazolidine ring attached to a beta-lactam ring)
Penicillin G Spectrum of Activity
Highly active against Gram positive (gp) bacteria and spirochetes (e.g. syphilis)
Penicillin G is destroyed by….
- Beta-lactamases
Penicillin G Route of Admin
- Acid labile –> Not used orally
- If a salt, must be IM
Penicillin V Route of Admin
- Oral formulation
What is the difference between Penicillin V and Penicillin G?
Pen V Counselling Tip?
Penicillin V –> Oral
Penicillin G –> Injection
Penicllin V ore acid stable but still needs to be taken on an empty stomach –> still very unstable
Natural Penicillins spectrum of activity Specific
- Streptococci
- Penumococci
- Meningococci
- Spirochetes
- Clostridia
- Anaerobic gram positive (strep)
- Actinomyces
- Enterococci
some people mention that slts can act amazingly everyday
Penicillins. What is there group name?
- Cloxacillin
- Flucloxacillin
- DIcloxacillin
Isoxazolyl penicillins
Define MSSA and MRSA. is methicllin used for pharmacotherapy?
MRSA –> Methicillin Resistant Staph Aureus –> Never give methicillin as a drug –> resistant to this whole class as well as all penicillin’s
Not a drug we give but a marker in the lab
- Also means cloxacillin resistance –> M is representative of the whole family
MSSA –> Methicillin Susceptible Staph Aureus –> Use cloxacillin (Canadian Name) –> Drug of choice
Isoaxyzol Penicllins are designed for… (which organism)
- Staphlococcus aureus
Isoxazolyl Penicillin Formulations
- IV and oral
Isoxazolyl Penicillin used in ….. infections
- Staphlococcal infections; not MRSA
Aminopenicillin Examples
- Ampicillin
- Amoxicillin
Aminopenicillins have activity against….
- Gram positive and negative organisms (limited negative coverage)
Cover more gram + than penicllins
Isoxazolyl penicillins and beta-lactmases
- Organisms that produce beta-lactmases are reisstant
Aminopenicillins are destroyed by….
- Beta-lactamases
Ampicillin Route of Admin
used IV; more acid stable than natural penicillins but poor bioavailability
Amoxicillin Route of Admin
What is amoxicillin combined with and what is its purpose?
used orally; better absorption than ampicillin; also available combined with clavulanic acid (beta-lactamase inhibitor)
Aminopenicillins spectrum Specific
Streptococci*
enterococci*
Neiserria sp.*
non-beta-lactamase producing H. influenzae E. coli
P. mirabilis
Salmonella
(slTS eat no homies pns sorry)
Clauvonic Acid MOA
Amoxicillin also available in combination with clavulanic acid
Clavulanic acid is a beta-lactamase inhibitor
Beta-lactamases open the beta- lactam ring of penicillins and cephalosporins ; no longer active
Classification of beta-lactamases depends on genetics, biochemical properties and substrate affinity for a beta-lactamase inhibitor
Ureidopenicllins Example
piperacillin
Piperacillin Spectrum
ACtive against which important organism
Increased activity against gn rods
Active against
Pseudomonas aeruginosa
Piperacillin Route of Admin
Parenteral Use
Piperacillin is avilable in combination with
Available combined with beta-lactamase inhibitor tazobactam
Penicllins are distributed…..
-Widely; including the CNS
Penicillins are excreted primarily by….
- Kidney
Penicllins are mainly taken on….. except for penicllin can be take with….
are taken on an empty stomach except amoxicillin
Drug Interaction of Penicllins
- Oral Contraceptives
Generally, the efficacy of estrogen is enterohepatic recirculation. With penicillins, you get destruction of estrogen and prevent enterohepatic recirculation. May get pregnant.
An unattended pregnancy can have huge consequences. Inform pt about using another form of contraception
Adverse effects of Penicllins
Allergic reactions – many people report allergies to antibiotics
Anaphylactic shock
Serum sickness*
Skin rashes
Fever
Nephritis
Eosinophilia
Seizures, Encephalopathy delirium
Electrolyte imbalances
Neutropenia, thrombocytopenia
Diarrhea, gi upset
