Antifungals, Beta-Lactams, and Fluoroquinolones: Key Concepts for Medical Students

antifungals

(-azole, -fine, -fungin)

triazole: strong inhibitors

itraconazole, voriconazole, posaconazole

triazoles _____ QT

lengthen

triazole that decreases QT

isavuconazole

no activity against aspergillus

fluconazole

best activity against aspergillus

voriconazole

gram positive cocci

staph and strep

staph

grows in clusters

strep

grows in pairs/chains

gram negative rod

e.coli

echinocandins

treat aspergillus

penicillin

treats strep, NOT staph

beta lactam MOA

binds to PBP, inhibits final transpeptidation steps of peptidoglycan synthesis, inhibits bacterial cell wall synthesis, lysis by autolytic enzymes, bacterial cell death

*same for all beta lactams

beta lactams

(CILLIN, CEF, CEPH, PENEM,BACTAM)

1st gen beta lactams

Cephalexin (PO)

Cefadroxil (PO)

Cefazolin (IV)

2nd gen beta lactams

better gram negative coverage than 1st gen

Cefaclor (PO)

Cefotetan (IV)

Cefoxitin (IV)

Cefprozil (PO)

Cefuroxime (PO,IV)

3rd gen beta lactams

ceftazidime: anti-pseudomonal, treat psuedomonas

ceftriaxone: CNS coverage, treat meningitis, common for hosptial use

4th gen beta lactams

best gram - coverage and gram + coverage

- Cefepime

5th gen beta lactams

MRSA activity

- ceftaroline

Carbapenems

PENEM

- broadest coverage

etrapenem

no activity against P. Aerginosa

*for COPD/ chronic bronchitis patients

Imipenem-cilastatin

seizures in patients w decreased renal function

Azteonam

for penicillin allergic patients

sulfonamide MOA

Competitive inhibitors of dihydropteroate synthase, the bacterial enzyme responsible for the incorporation of PABA into dihydropteroic acid, the immediate precursor of folic acid

- Competitive antagonism of PABA

Trimethoprim-Sulfamethoxazole (TMP-SMX) adverse reactions

bone marrow supression, renal impairment

tertracycline MOA

inhibit bacterial protein synthesis by binding to 30S bacterial ribosome and preventing access of aminoacyl tRNA to acceptor site of mRNA ribosomal complex

Tigecycline Black Box Warning

• Increased all-cause mortality versus comparators in phase 3 and 4clinical trials

• Treatment of hospital-acquired pneumonia (HAP) or ventilator-associated pneumonia (VAP)

tigecycline adverse reactions

photosensitivity, gi stress

*not used in children under 8 (permanent tooth discoloration)

-pregnancy category D

FLOXACIN (Fluoroquinolones) MOA

inhibits topoisomerase II (DNA gyrase) and IV which inhibits relaxation of supercoiled DNA and promotes DNA breakage

Fluoroquinolones

Ciprofloxacin ( PO and IV) Ofloxacin

Levofloxacin (PO and IV)

Moxifloxacin (PO and IV)

Delafloxacin (PO and IV)

*broad spectrum antibiotics

Fluoroquinolone black box

Tendinopathy/tendon rupture (frequently Achilles tendon, older adults higher risk)

fluoroquinolone in pediatric use

management of cystic fibrosis with caution

*Musculoskeletal disorders: concern in pediatrics