Week 12-14 Flashcards
Beta-lactams: Mechanism of Action
Inhibit bacterial cell wall synthesis by binding to penicillin-binding proteins (PBPs), preventing peptidoglycan cross-linking.
Beta-lactams: Classes
Include penicillins, cephalosporins, carbapenems, and monobactams.
Penicillin G: Use
Used parenterally for syphilis and streptococcal infections; not stable in stomach acid.
Penicillin V: Use
Oral form used for mild streptococcal infections due to acid stability.
Amoxicillin: Use
Broad-spectrum oral penicillin used for otitis media, sinusitis, and respiratory tract infections.
Ampicillin: Adverse Effects
May cause gastrointestinal upset due to incomplete absorption.
Piperacillin-Tazobactam: Use
Extended-spectrum penicillin combination used for serious hospital-acquired and intra-abdominal infections, covers Pseudomonas.
1st Generation Cephalosporins: Use
Used for MSSA skin infections and surgical prophylaxis (e.g., cefazolin, cephalexin).
2nd Generation Cephalosporins: Use
Effective for respiratory and intra-abdominal infections; active against H. influenzae and anaerobes (e.g., cefuroxime, cefoxitin).
3rd Generation Cephalosporins: Use
Broad gram-negative activity; used for meningitis and pneumonia (e.g., ceftriaxone, ceftazidime).
4th Generation Cephalosporins: Use
Effective against Pseudomonas and Enterobacteriaceae; used in febrile neutropenia (e.g., cefepime).
5th Generation Cephalosporins: Use
Active against MRSA and resistant gram-positive organisms (e.g., ceftaroline).
Fluoroquinolones: Mechanism of Action
Inhibit DNA gyrase (gram-negative) and topoisomerase IV (gram-positive), blocking DNA replication.
Ciprofloxacin: Use
Effective against gram-negative infections including Pseudomonas; used for UTIs, GI infections.
Levofloxacin: Use
Improved gram-positive coverage; used for pneumonia, UTIs, skin infections.
Moxifloxacin: Use
Covers anaerobes and gram-positives; not used for UTIs due to low urinary concentration.
Fluoroquinolones: Adverse Effects
Tendon rupture, CNS toxicity, QT prolongation, peripheral neuropathy, dysglycemia.
Fluoroquinolones: Absorption Concern
Chelation with divalent/trivalent cations (e.g., calcium) reduces absorption.
Tetracyclines: Mechanism of Action
Bind to 30S ribosomal subunit, blocking tRNA binding and inhibiting protein synthesis (bacteriostatic).
Tetracyclines: Adverse Effects
Tooth discoloration, GI upset, hepatotoxicity, photosensitivity, intracranial hypertension, vestibular effects.
Doxycycline: Use
Used for tick-borne diseases, respiratory infections, and in penicillin-allergic patients.
Doxycycline: Elimination
Preferred in renal impairment due to fecal elimination.
Aminoglycosides: Mechanism of Action
Bind to 30S subunit, causing misreading of mRNA and disrupting protein synthesis (bactericidal).
Aminoglycosides: Use
Used for aerobic gram-negative bacilli; ineffective in anaerobic infections.
