Antibiotics Part 2 & Respiratory Part 1

4 classes of penicillins

• natural penicillin

• penicillinase-resistant penicillin

• aminopenicillin

• antipseudomonal penicillin

Where does natural penicillin come from?

penicillium mold spores

Spectrum of Activity

range of organisms the antibiotic is likely to kill

Spectrum of activity for natural pencillin

non-beta lactamase producing gram-positive cocci and spirochetes

Beta lactamase

an enzyme created by bacteria that breaks the beta lactam ring open which deactivates the molecules antibiotic activity

Beta lactamase can be transferred to other bacteria through ___ ___

plasmid transfer

3 types of beta lactamase

• penicillinase

• extended spectrum beta lactamase

• carbapenemase

Species that natural penicillin kills

• streptococci

• enterococcus faecalis

  • treponema pallidum (syphilis-causing organism)

aqueous PCN G

natural penicillin

How often must aqueous PCN G be administered?

every 4-6 hours

Wycillin

natural penicillin

How often is Wycillin administered?

every 12-24 hours

Bicillin

natural penicillin

How many times is Bicillin administered?

once (IM shot)

Penicillin VK

natural penicillin

How often is penicillin VK administered?

every 6-8 hours

What is the only penicillin drug class that is not destroyed by penicillinase?

penicillinase-resistant penicillin

What antibiotic used to treat MRSA but no longer can because the pathogen developed 2 forms of resistance to it?

penicillinase-resistant penicillin

Spectrum of activity for penicillinase-resistant penicillin

Gram +, penicillinase-producing staph aureus, streptococcus (we’d prefer to use a natural pencillin)

Prostaphlin

penicillinase-resistant penicillin

Unipen

penicillinase-resistant penicillin

Dynapen

penicillinase-resistant penicillin

Tegopen

penicillinase-resistant penicillin

Tegopen & Dynapen are used to treat what?

staph and strep

What is the most commonly used penicillinase-resistant penicillin?

Unipen

What is another name for aminopenicillin?

extended spectrum penicillin

Spectrum of activity for aminopenicillins

some non-beta lactamase producing Gram-negative

Organisms that aminopenicillin kills

• H. Influenzae

• E. Coli

• N. meningitidis

all URI-causing pathogens

ampicillin

aminopenicillin

Unasyn

aminopenicillin

ampicillin+sulbactam

Unasyn

Amoxicillin

aminopenicillin

Augmentin

aminopenicillin

amoxicillin+clavulanic acid

aminopenicillin

What is the most commonly used aminopenicillin?

amoxicillin

Why is amoxicillin the most commonly used aminopenicillin?

it has fewer GI side effects

What is the most broad-spectrum penicillin?

antipseudomonal penicillin

What is the spectrum of activity for antipseudomonal penicillins?

• gram-negative

• gram-positive

• aerobes

What are beta-lactamase inhibitors?

a chemical added to penicillin that ties up beta-lactamase so it won’t work to be resistant

beta-lactamase inhibitors are added to which classes of penicillin?

aminopenicillin & antipsuedomonal penicillin

Pipracil

antipseudomonal penicillin

Zosyn

antipseudomonal penicillin

pipracil+tazobactam

Zosyn

Geocillin

antipseudomonal penicillin

What does tazobactam do?

inhibit beta lactamase

What are the 5 classes of cephalosporins?

• first gen

• second gen

• third gen

• fourth gen

• fifth gen

How are cephalosporins classified?

by their spectrum of activity

ancef

first generation cephalosporin

duracef

first generation cephalosporin

velocef

first generation cephalosporin

Spectrum of activity for first generation cephalosporins

• gram-positive aerobes and anaerobes

• moderate against some gram-negative (don’t use it for that)

Spectrum of activity for second generation cephalosporins

• gram-positve aerobes & anaerobes

• 3 common URI gram-negative pathogens

  • H. influenzae

  • M. catarrhalis

  • N. meningitidis & N. gonorrhea

Zinacef

second generation cephalosporin

Mefoxin

second generation cephalosporin

Cefotan

second generation cephalosporin

Ceclor

second generation cephalosporin

Cefzil

second generation cephalosporin

Ceftin

second generation cephalosporin

Spectrum of activity for third generation cephalosporins

• excellent gram-negative coverage

• less active against gram-positive than 1st or 2nd gen

Claforan

third generation cephalosporin

Rocephin

third generation cephalosporin

Fortaz

third generation cephalosporin

Spectrecef

third generation cephalosporin

Omnicef

third generation cephalosporin

Cedax

third generation cephalosporin

Maxipime

fourth generation cephalosporin

Spectrum of activity of Maxipime

• very broad, kills everything

• gram-positive + gram-negative

Ancef + Fortaz

Maxipime (combines 1st and 3rd gen cephalosporins)

Clinical use for fourth generation cephalosporins

empiric therapy for febrile neutropenia & nosocomial pneumonia

Strategy for use for fourth generation cephalosporins

typically will step down once culture & sensitivity is known and use an antibiotic with a narrower spectrum (we don’t want to grow resistance)

What are fourth generation cephalosporins destroyed by

extended spectrum beta lactamase (ESBL)

Taflaro

fifth generation cephalosporin

Zevtera

fifth generation cephalosporin

Spectrum of activity for fifth generation cephalosporin

• gram-positive including MRSA

• less gram-negative than 4th gen

Clinical use for fifth generation cephalosporins

MRSA (skin, soft tissue, & pneumonia)

We typically only use a fifth generation cephalosporin for what?

MRSA. We don’t use it for other gram-positive pathogens because we don’t want to drive resistance.

Azactam

monobactam

What is the only beta lactam that is safe to use in a patient with a true allergy?

azactam

Spectrum of activity for azactam

• gram-negative bacteria

• similar to 3rd gen cephalosporins

• no cross-reactivity with other beta lactams

Clinical use for azactam

used as a substitute for a 3rd generation cephalosporin in a patient with a type 1 penicillin/beta lactam allergy

-penem

carbapenems

Spectrum of activity for carbapenems

• very broad

  • gram-positive & gram-negative pathogens

Clinical use for carbapenems

• empiric therapy (pathogen is unknown)

  • severe systemic infections

  • mixed infections (multiple organisms causing an infection)

non-beta-lactam antibiotics

• glycopeptides

• aminoglycosides

• fluoroquinolones

• macrolides

• tetracyclines

• miscellaneous agents

Vancomycin

glycopeptides

telavancin

glycopeptide

Spectrum of activity of glycopeptides

excellent gram-positive aerobes & anaerobes

What organisms is a glycopeptide used to treat?

• MRSA (can’t count on it bc of increasing resistance)

• C. Diff

ADRs for glycopeptides

• red man syndrome (histamine release causing vasodilation and more blood to rush into skin)

  • dose & infusion rate dependent

• nephrotoxicity

• ototoxicity

• phlebitis

Fluoroquinolones spectrum of activity

• mixed gram-positive

  • good staph w/ increasing resistance

  • moderate strep activity

• very good gram-negative

  • E. Coli, H. flu, M catarrhalis

Clinical use for fluoroquinolones

• upper respiratory tract infections

• uncomplicated UTI’s

• complicated UTI’s

• skin

-flaxin

fluoroquinolones

Which type of antibiotic has a black box warning?

fluoroquinolones

What is the black box warning for fluoroquinolones?

they have been associated with disabling and potentially irreversible adverse reactions including: tendon rupture, peripheral neuropathy, CNS effects (hallucinations, anxiety, depression, insomnia, severe headaches, confusion)

Reserve fluoroquinolones for patients who have no alternate treatment options for:

• acute bronchitis

• uncomplicated UTI’s

• acute sinusitis

In what condition do the risks of not taking the fluoroquinolone outweigh the side effects of the fluoroquinolone?

complicated UTI because it can lead to a bad kidney infection

macrolide spectrum of activity

• gram-positive

• some gram-negative

• genital pathogens (STIs)

  • N. gonorrhoeae

  • Chlamydia

  • Treponema pallidum (syphilis)

Clinical use for macrolides

respiratory tract infections, skin & soft tissue, STI

ADRs of macrolides

• nause

• vomiting

• abdominal pain

• diarrhea