Penicillin's Exam 1 Drug List Flashcards
Beta-Lactams Common Characteristics
Broad class of antibiotics with several sub-groups
Share common structure featural beta-lactam ring.
Beta-Lactam Antibiotic Subgroups
Penicillins
Cephalosporins
Carbapenems
Monobactams
Beta-Lactams (Penicillin V, Benzathine/Procaine Penicillin G, Amoxicillin, Amoxicillin/clavulanate) MOA
Inhibition of cell wall synthesis
Bind to PBPs
Inhibits final stage of cell wall construction
Weakens cell wall leading to cell lysis
Especially in dividing bacteria
Beta-Lactam Indications
Respiratory tract infections
UTIs
Skin soft tissue infections
Septicemia
Meningitis (ceftriaxone)
Beta-Lactams Efficacy Depends on?
Time-Dependent Killing
Duration at which concentration exceeds the MIC of the pathogen for 40-60% of dosing interval
Beta-Lactams are most effective against?
Rapidly replicating organisms
Bacterial enzymes responsible for cell wall/peptidoglycan synthesis
Transpeptidase
Carboxypeptidase
Endopeptidase
Beta-Lactam Penicillin absorption
Penicillin V (PO) GI tract, presence of food delays/decreases, take on empty stomach
Procaine Penicillin G (IM) slow and prolonged, sustained blood levels
Benzathine Penicillin G (IM) Very slow, very low but prolonged blood levels
Beta-Lactam Penicillin Distribution
Widely distributed throughout body Penetrates tissues and body fluids.
Limited penetration into the CSF unless meninges are inflamed
Penicillin V (PO) 80% protein-bound in plasma
Procaine/Benzathine penicillin G (IM) 60% protein-bound in plasma
Beta-Lactam Penicillin Metabolism
Penicillin V (PO) minimal metabolism, inactive metabolites in liver.
Procaine penicillin G (IM) minimal metabolism, procaine is hydrolyzed to PABA
Benzathine penicillin G (IM) minimal metabolism
Beta-Lactam Penicillin Excretion
Primarily by kidneys
Dose adjustment in renal impairment
90% renal by active tubular secretion
Penicillin V (PO) drug is unchanged in urine within 24 hrs.
Procaine penicillin G (IM) Majority of drug is unchanged in urine.
Benzathine penicillin G (IM) Majority of drug is unchanged in urine.
Common Beta-Lactam Side effects
GI upset, rash, allergic reactions
IM injection site reactions
Serious Beta-Lactam Side effects
Hypersensitivity reactions including
Steven-Johnson Syndrome
Toxic epidermal necrolysis
C-Diff
Beta-Lactam Contraindications
Hypersensitivity to beta-lactams
Cross-sensitivity with penicillins and cephalosporins
What things cause Beta-Lactam Resistance?
Beta-Lactamase production (hydrolysis beta-lactam ring)
Use clavulanic acid, tazobactam to counter act beta-lactamase
Altered PBPs (Reduces affinity of beta-lactams)
Efflux pumps and porin changes (cell membrane permeability)
Need to know Penicillins
Penicillin V (PO)
Penicillin G (IM)
Amoxicillin
Amoxicillin/clavulanate
Natural Penicillins
Penicillin V (PO)
Penicillin G (IM)