Beta Lactam Abx Flashcards
What are the classes of cell wall synthesis inhibitors?
- Beta-lactam Abx
- -Penicillins
- -Cephalosporins
- -Carbapenems
- -Monobactams
-Beta-Lactamase Inhibitors
What is the MOA of Beta-Lactam Abx?
- inhibiting cell wall biosynthesis, essentially the abx is inhibiting transpeptidation (the cross-linking of …?)
- bactericidal to GROWING bacteria
What is the common mechanism in which bacteria often develop resistance to beta-lactam abx?
How do we overcome the problem of resistance?
- the bacteria synthesize B-lactamase, an enzyme that breaks down the beta-lactam ring and inactivates the abx (essentially this is the metabolism of the drug)
- Beta-lactam abx are often given with Beta-lactamase inhibitors such as clavulanic acid (Augmentin)
What is the main structure of Beta-Lactam Abx?
-main structure consists of beta-lactam ring, essential for the activity of abx against a pathogen.
Penicillin Classication
- Penicillin G
- Antistaphlococcal PCN
- -nafcillin, dicloxacillin, oxacillin, cloxacillin
- Broad Spectrum PCN
- -2nd generation
- –ampicillin, amoxicillin
- -3rd Generation
- –Carbenicillin, ticarcillin
- -4th Generation
- –Piperacillin
What are the penicllin combos w/ beta-lactamase inhibitiors
- Augmentin
- Unasyn
- Timentin
- Zosyn
If you have an allergic rxn to a penicillin does this imply you will have an allergic rxn to all of the other sub-classes of penicillin?
-yes, allergic rxn to one PCN are cross reactive to others.
Do abx interfere with host flora?
YESSS!!!
Which abx can cause C-diff?
-ALLLL OF THEM!
Penicillin G
- use
- active against which type of bacteria?
- Routes of Admin and how long do they last?
- When should you adjust the dosing of this medication?
-tx infections (sepsis, pneuomonia, pericarditis, endocarditis, meningitis, anthrax)
- gram + cocci
- gram + rods
- gram - cocci
- most anaerobes
- IM (10-12days) IV, PCN VK(only oral form)(good for strep throat)
- adjust dose for renal failure, no adjustment needed for hepatic dysfunction.
IM Penicillin G can be used for?
IV Penicillin G can be used for?
IM- strep, syphilis
IV- meningitis and endocarditis , erysipelas, neurosyphilis
Adverse Rxns/Warnings of Penicillin G
- local; injection site rxn
- CNS: coma, hyperreflexia, myoclonus (involuntary muscle spasm), seizure
- Hematolgic & oncologic: neutropenia, + coombs test (looks for autoimmune hemolytic anemia)
- Hypersensitivity: anaphylaxis, hypersensivity rxn, serum sixkness
- Renal: acute interstitial nephritis
- superinfection: prolonged used may result in fungal or bacterial superinfection, including C-diff and pseudomembranous colitis.
Drug Interactions w/ Penicillin G, 2nd generation PCN,
BCG: abx diminish effect of BCG vaccine, RIsk X
Methotrexate: penicillin may increase serum concentration of methotrexate, Risk C
Probenecid: may increase serum conc. of Penicillin Risk C
Sodium Picosulfate: Abx may diminish effects of sodium picosulfate; Risk D (consider therapy modification)
Tetracycline: may diminish effects of penicillin, Risk D
Vit K antagonists: Penicillin may enhance anticoag effect of vit K antagonist.
OBCP (oral birth control pills): may decrease contraceptive efficacy.
What is the drug of choice for most strep pharyngitis?
-Penicillin VK
What are the antistaphylococcal PCNs?
- activity?
- dose adjustments?
- dicloxacillin, oxacillin, nafcillin
- infection w/ beta-lactamase-producing staph, strep & pneumo.
- no dose adjustments are required (liver or renal)
Routes of Administration of Antistaphylococcal PCN?
- Dicloxacillin- PO
- Oxacillin- IM or IV
- Nafcillin- IV
Adverse SE of Antistaphylococcal PCN?
- GI; nausea, diarrhea, abd pain
- > 1%hemolytic anemia
Drug interactions of Antistaphylococcal PCN?
- Calcium channel blockers: may increase the metabolism of calcium channel blockers.
- contraceptives w/ estrogen: increase metabolism of estrogen, use non-hormonal form of contraceptive.
- Vit K antagonists: (warfarin) may diminish anticoagulant effects.
Broad Spectrum PCN:
- 2nd generation
- 3rd generation
- 4th generation
2- ampicillin, amoxicillin
3- carbenicillin, ticarcillin
4- piperacillin
Second Generation PCN uses,
- Adverse SE
- dose adjustments?
- Not recommended for which population?
-otitis, sinusitis, RTI
SE:
- CNS: anxiety, agitation, confusion, dizziness, HA, seizure
- Hematologic: agranulocytosis, hemolytic anemia, thrombocytopenia purpura
- Renal: crystalluria
- Misc: anaphylaxis
- Renal adjustment, no hepatic adjustments
- not recommended in those with mono. may induce rash.
Third Generation PCN
-routes of admin
-IV only
What is the standard therapy as anti-pseudomonal medications in hospitals?
-3rd generation PCN
4th Generation PCN
-adjustments needed?
Renal adjustments.
What are the PCN combo drugs that help combat resistant bacteria?
- 2nd Generation: Augmentin
- 3rd generation: Temectin
- 4th generation: Zosyn
