Antibiotics Part 1 Flashcards
Drugs that weaken the bacterial cell wall? Are they bactericidal?
Penicillin, Cephalosporins, Carbapenems, Vancomycin
-Yes they cause lysis
Prototype for Penicillin
Penicillin G (-cillin) Least toxic of all penicillins
Penicillin MOA
Inhibition of bacterial cell wall
Penicillin #1 Adverse effect to look for!
- Cause of most allergies
- cross-sensitivity w/ cephalosporins
- Immediate: 2-30 mins
- Accelerated 1-72 hours
- Late: days to weeks
- Mild - Anaphlyaxis
- No direct relationship btwn dose and size of allergic repsonse
- must have 2nd exposure for allergic response
Other Penicillin Adverse Effects
- Pain at injection site
- sensory/ nerve dysfunciton
- risk of hyperkalemia w/ potassium PCN- G
- Neurotoxicity
- gangrene/ necrosis w/ intra-arterial
Route of Penicillin
IV or IM
-some are repository form
Penicillin Interactions
- Cross sensitivity with cephalosorins
- avoid using cephalosporins if pt has severe allergic rxn
How to treat a penicillin allergy?
- Give epi, repository measures, n/v/d
- Skin tests for PCN
What is desensitization process?
- When a patient needs PCN but are highly allergic
- must be administered in ICU setting for risk of anaphylaxis
- Given PCN in small doses every 60 mins until they reach full dose
What are beta-lactamases
- combo of PCN + beta-lactam inhibitor
- Amoxicillin + clavulanate
- the inhibitor prevents the break down of the beta lactam ring and inhibition of PCN
Beta-lactamases MOA
- Cell wall inhibitors
How long are beta lactamases administered for?
-Needs to be infused over 30 min or longer to extend MIC
What about adverse effects with beta-lactamases?
- caused by penicillin aspect of combo
What are Cephalosporins and MOA?
- Most widely used abx
- low toxicity
- They weaken the cell wall
Cephalosporin Route?
IV or IM
-some are oral
What are generations (1-5)?
- Increase in activity from 1-5 against gram negative and anaerobes
- Increase resistance to destruction from beta-lactamases and to reach CSF from 1-5
Cephalosporin Adverse Effects
- Allergy: cross-sensitivity to PCN
- Rash most common (occurs several days after start of therapy)
- GI distress: N/V/D, abdominal cramps
- Anorexia
- IM injections painful
Cephalosporin Interactions
- Cefotetan & Ceftriaxone have increased bleeding risk
- Cefotetan& cefazolan have dilsufram effect w/ alcohol
- Ceftriaxone: don’t mix w/ lactated ringers and is elminated by liver
Carbapenems Prototype
Imipenum/Cilastin (Primaxin)
-combo prevents destruction of impipenum by renal enzymes
Carbapenems MOA
Cell Wall inhibitor
Carbapenem Adverse effects
- GI distress
- Allergy
Carbapenem Interaction
- Valproate acid (seizure med)
- reduces level of this drug
Vancomycin MOA
Cell Wall Synthesis inhibitor
- Kills gram + only
- MRSA, C-Diff, serious infections
What is the drug of choice for MRSA?
Oral Vancomycin
