26 + 27: Antibiotics Flashcards
5 MOAs of antibiotics
- inhibit cell wall synthesis
- alteration of membrane permeability
- inhibition of protein synthesis
- inhibition of synthesis of bacterial RNA and DNA
- interference w/ cellular metabolism
3 types of abx combo effects
- additive (effect is doubled)
- potentiative (multiplied effects)
- antagonistic (if one is bacericidal and one is bacteriostatic)
general adverse reactions to abx
- allergic reactions
- superinfection
- organ toxicity: ear, liver, kidney
structure of beta-lactam abx
name derived from beta-lactam ring -> essential for antibacterial activity (cell wall lysis)
how is resistance developed against beta-lactam abx
specific enzymes can disrupt ring and inactivate MOA (beta-lactamase enzyme produced by bacteria -> resistance)
examples of beta-lactam abx
- penicillins
- cephalosporins
- carbapenems
- monobactams
MOA of penicillins
- inhibit bacterial cell wall synthesis (beta-lactam structure)
- bacteriostatic and bactericidal effects depending on drug dose
types of penicillins
- basic
- broad-spectrum
- penicillinase-resistant
- extended-spectrum
uses of basic penicillins
narrow spectrum
- gram (+) and a few gram (-) bacteria
- streptococcus and Clostridium species
- Neisseria and staphylococcus species
- treats anthrax, tetanus, diphtheria, endocarditis, respiratory infections, and syphilis (injectable)
example of a broad-spectrum penicillin
Amoxicillin
uses of amoxicillin
treat bacterial infections caused by variety of different bacteria (broad spectrum)
side effects/adverse effects of amoxicillin
- hypersensitivity
- anaphylaxis
- superinfection (ex. yeast infections)
- tongue discoloration and stomatitis
- GI distress
- C diff associated diarrhea
black box warning for penicillin G (broad-spectrum penicillin)
inadvertent IV administration of penicillin G benzathine can cause cardiopulmonary arrest and death
MOA of beta-lactamase inhibitors
inhibit bacterial beta-lactamases extending antimicrobial spectrum
what are beta-lactamase inhibitors combined with
- penicillinase-sensitive penicillin
- piperacillin tazobactam, ampicillin sulbactam (parentral), amoxicillin clavulanate (oral)
characteristics of cephalosporins
- beta-lactam structure
- derived from fungus
- 5 groups (first, second, third, fourth, and fifth generation)
uses of cephalosporins
- broad-spectrum antibiotic w/ activity against gram (+) and gram (-) bacteria
- more activity against gram (-) compared w/ penicillins
describe 1st generation cephalosporins
effective against most gram (+) and some gram (-) bacteria
bacteria affected by 1st generation cephalosporins
- staphylococci
- streptococci
- E. coli
- Klebsiella
- Proteus
- Salmonella
- Shigella
describe 2nd generation cephalosporins
effective against gram (+) and gram (-) bacteria
bacteria affected by 2nd generation cephalosporins
- staphylococci, streptococci, E. coli, Klebsiella, Proteus, Salmonella, and Shigella (like 1st gen)
- Haemophilus influenza
- Enterobacter
- Neisseria gonorrhea
- Nesseria meningitis
example of 1st generation cephalosporin
cefalexin (useful for common skin infection and cellulitis; not effective against MRSA)
example of 2nd generation cephalosporin
Cefuroxime (useful for otitis media, sinus infection, and pneumonia)
describe 3rd generation cephalosporins
- effective against gram (+) and gram (-) bacteria
- has increased resistance to destruction by beta-lactamases