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)
Penicillin V and Benzathine/Procaine Penicillin G MOA
Inhibits bacterial cell wall synthesis binding PBPs leading to cell lysis
Common Side Effects of Penicillin V (PO), Benzathine/Procaine Penicillin G (IM)
Nausea, Vomiting, diarrhea, rash, anaphylaxis (rare)
Injection site reaction (Pain, redness, swelling)
Penicillin V Monitoring
Renal function
Signs of allergic reactions
Hematologic parameters in prolonged therapy
Black Box Warning for Penicillin V
No black box warning
Black Box Warning for Procaine/Benzathine Penicillin G
Avoid injections near veins and arteries. Can cause cardiac arrest.
Major ADRs Penicillin V
Anaphylaxis, SJS, toxic epidermal necrolysis, C-Diff, Hemolytic anemia, thrombocytopenia, leukopenia
Major ADRs Benzathine Penicillin G (IM)
Severe allergic reactions
SJS
Toxic epidermal necrolysis
C-Diff
Hemolytic anemia
Thrombocytopenia
Leukopenia
Neurotoxicity (High doses, or renal impairment can lead to seizures)
Is Benzathine/Procaine Penicillin G (IM) Penicillin V (PO) Bacteriostatic or Bactericidal?
Bactericidal (kills rather than inhibiting)
What do penicillins bind to?
Plasma protein Bound
Do Penicillins cross the placenta and breast milk?
Yes
Natural penicillins are active against?
Aerobic, gram-positive organisms, streptococcus species (S. Pneumoniae, Group A beta-hemolytic streptococcus, some enterococcus, Some non-penicillinase producing staphylococci.
5-15% of Community-aquired staphylococcus aureus remain susceptible to natural penicillins because
Penicillinase hydrolyzes the beta-lactam ring rendering them completely ineffective
Penicillin-Resistant Streptococcus Pneumoniae prevalence is down because
Vaccinations PCV 13,15,20
Beta-Lactam Aminopenicillins
Amoxicillin
Amoxicillin/clavulanate
Amoxicillin MOA
Inhibition of cell wall synthesis
Bind to PBPs
Inhibits final stage of cell wall construction
Weakens cell wall leading to cell lysis
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
Inhibits beta-lactamase produced by bacteria, protecting amoxicillin, extending spectrum activity
Amoxicillin Indications
CAP
Acute Otitis media
Sinusitis
Lyme disease
Chronic bronchitis
DRSP
Amoxicillin/clavulanate Indications
CAP
Serious or resistant infections
Acute exacerbation of chronic bronchitis
Acute otitis media/sinusitis
Animal bites
Amoxicillin/clavulanate excellent activity against?
Staphylococcus aureus (MSSA), Streptococcus, enterococcus, H influenzae, N meningitidis, salmonella, some shigella species
Amoxicillin and Amoxicillin/Clavulanate Common Side Effects
GI upset
Rash
Allergic reactions
Amoxicillin and Amoxicillin/Clavulanate Monitoring
Renal function (specifically those with renal impairment)
Signs of allergic reaction (rash, itching, swelling, respiratory difficulties)
Hepatic function during prolonged therapy (clavulanate can cause hepatic dysfunction)
Amoxicillin and Amoxicillin/Clavulanate ADRs
Severe allergic reactions
SJS
Toxic epidermal necrolysis
C-Diff
Hemolytic anemia
Thrombocytopenia
Leukopenia
Hepatic dysfunction (jaundice/hepatitis more common with clavulanate)
Is Amoxicillin and Amoxicillin/Clavulanate Bacteriostatic or Bactericidal?
Bactericidal
Do Amoxicillin and Amoxicillin/Clavulanate cross BBB, placenta, and into the breast milk
Only if meninges are inflamed
Yes, cross placenta (Safe during pregnancy when indicated
Yes, small amounts are excreted into breast milk (can cause GI upset and allergic reactions to nursing infant)
Leading Risk Factors leading to Resistance
Recent use of antimicrobials
Multiple medical comorbidities
Recent hospitalization or other skilled healthcare contact
Bactericidal
Refers to 99.9% eradication of a bacterial colony in vitro in 24 hrs by an antimicrobial.
Bacteriostatic
Refers to an abx that kills bacteria but the result is less than 99.9% eradication in a 24hr period.
