antibiotics Flashcards
Inhibitors of cell wall synthesis
Beta-Lactams penicillins
Cephalosporins
Glycopeptides: vancomycin
TB medications
Inhibitors of translation and transcription
Tetracyclines Macrolides Clindamycin Oxazolidinones: linezolid Aminoglycosides and Spectinomycin TB medications
Inhibition of DNA syntheses and integrity/
Inhibitors of folate synthesis and function
Sulfonamides,
Trimethoprim
Quinolones
Bactericidal
Mechanism is generally inhibition of cell wall synthesis
Time-dependent killing: serum level above MIC
Beta lactams and vancomycin
Concentration-dependent killing: higher drug concentration determines rate and extent of killing
Aminoglycosides and quinolones
Bacteriostatic
Mechanism is generally inhibition of protein synthesis
Weakens so body can kill
Tetracyclines, macrolides, sulfonamides
contraindicated in renal impairment
nitrofurantoin, sulfonamides (long-acting),
tetracyclines
adjust dosage if renal impairment
, aminoglycosides, carbapenems, cephalosporins
trimethoprim-sulfamethoxazole, vancomycin
adjust dosage in hepatic impairment
metronidazole
chloramphenicol, clindamycin, erythromycin
clindamycin, erythromycinine
narrow spectrum PCN
Peniciilinase-susceptible Penicillin G Penicillin VK Penicillinase–resistant Nafcillin Oxacillin PCN for strept pyogenes aka strept throat
wide spectrum PCN
(+/−) penicillinase inhibitor Ampicillin Amoxicillin (for H. influenza PCN doesnt work) Piperacillin Ticarcillin
PCN PK ADE
PK: rapid renal elimiination
ADE: hypersensitivity (5%) cant breath
maculopapular rash from ampicillin
PCN treats
Narrow spectrum Streptococcal infections Staphylococcal infections Meningococcal infections Syphilis
Wider spectrum
Greater activity vs gram-negative bacteria
Cephalosporins
First generation (narrowest) Cephalexin Second generation Cefuroxime Third generation Ceftriaxone* Cefixime same class as PCN so give if PCN allergy
Cephalosporins PK ADE
PK: Oral use for older drugs Mostly IV for newer drugs Renal elimination Third-generation drugs enter CNS ADEs Hypersensitivity reactions (~2%) complete cross-reactivity between cephalosporins First generation partial cross-reactivity with penicillins
cephalosporin contraindicated
No ceftriaxone to newborns b/v its cleared by billary tract and newborns cannot clear
Cephalosporin activity
First generation: Skin, soft tissue, UTI Second generation: More active vs S pneumoniae and H influenza; B fragilis (cefotetan) Third generation: Many uses including pneumonia, meningitis, and gonorrhea Broad activity, beta-lactamase-stable Fourth generation: Pseudomonas coverage Fifth generation: Skin, soft tissue CAP community acquired pneumonia
Carbapenems
Imipenem-cilastatin (Primaxinbroad spectrum:
some PRSP strains (not MRSA)
gram-negative rods
Pseudomonas sp
ADEs:
CNS effects include confusion and seizures
beta lactams
penicillin derivatives (penams), cephalosporins (cephems), monobactams, and carbapenems
Monobactams
Aztreonam only for gram -bacteria: Klebsiella Pseudomonas Serratia spp ADEs: CNS Headache Vertigo No cross-allergenicity with other beta-lactams
glycopeptides
vancomycin covers MRSA and PRSP Activity Spectrum Gram-positive activity includes MRSA and PRSP strains
glycopeptides PK/ADE
PK: Parenteral for systemic infections ORAL vancomycin for C difficile colitis Renal elimination Toxicities: Red-neck or red man syndrome Erythematous rash on face and upper body Infusion rate cause and not an allergic reaction Rare nephrotoxicity
Daptomycin
Daptomycin
Lipopeptide
ADE: myopathy as a unique toxicity: myopathy so monitor CK weekly
Daptomycin for:
Activity Spectrum Gram-positive activity Endocarditis and sepsis Off-labeled uses Osteomyelitis Prosthetic join infections MSSA and MRSA coverage
Tetracyclines
Doxycycline bind to 30S ribosomal subunit inhibits transcription/translation for: Acne CAP, bronchitis Cellulitis (purulent) due to CA-MRSA Off-label use Lyme disease Periodontitis Acute bacterial rhinosinusitis (off-label use)
Tetracyclines ADE
ADEs
GI upset (take with cola not milk) repeat if puke <1hr
Interaction with di and trivalent ions (that milk has)
Deposition in developing bones and teeth
Photosensitivity (wont looked burned but act burned)
CONTRAINDICATED: in pregnant and <8
Tetracyclines activity
Anthrax Chlamydial Mycoplasma Rickettsiae RMSF Typhus Spirochetes Lyme disease, relapsing fever Syphilis H pylori regimens
Macrolides
Azithromycin (zpack) bind to 50S ribosomal subunit inhibits transcription/translation for:CAP Pertussis, Corynebacteria Diphtheria Chlamydial Prokinetic affect: increase GI motility diarrhea
Macrolides
GI upset Hepatic dysfunction QT elongation CYP450 inhibition not azithromycin
Lincosamides
Clindamycin bind to 50S ribosomal subunit inhibits transcription/translation for: Skin, soft tissue infections Anaerobic infections (diaphragm up) ADE: Can cause C difficile colitis (highest incidence)
Chloramphenicol
Chloramphenicol bind to 50S ribosomal subunit inhibits transcription/translation serious infections due to organisms resistant to less toxic antibiotics Bacteroides H. influenza Neisseria meningitides Salmonella Rickettsia Active against many vancomycin-resistant enterococci
Chloramphenicol
Dose-related anemia Frequent monitoring of CBC Gray baby syndrome so contraindicated in babies Symptoms: Circulatory collapse Cyanosis Acidosis Abdominal distention Myocardial depression Coma Death Risks Serum levels > 50mcg/ml Patients with impaired hepatic or renal function
Oxazolidinone
Linezolid bind to 23S ribosomal subunit inhibits transcription/translation for: MRSA PRSP VRE strains (vanco resistant enterococci)
Oxazolidinone ADE
Dose-related anemia
Neuropathy
Optic neuritis
Serotonin syndrome with SSRIs
Aminoglycosides
gentamicin and tobramycin
inhibit protein synthesis via binding to 30S ribosomal subunit
For: Aerobic gram-negative bacteria
H, influenza
M. catarrhalis
Shigella species
Often used in combinations with beta-lactams (empiric)
Aminoglycosides: ADE
Nephrotoxicity (reversible),
Ototoxicity (irreversible),
Neuromuscular blockade (used in surgery so dont mix with surgery blockers)
Inhibition of DNA syntheses and integrity and Inhibitors of folate synthesis and function
Sulfonamides, Trimethoprim, Quinolones
antifolate antibiotics
sulfonamide and trimethoprim: block folic acid synthesis
fluoroquinolones: interfere with bacterial DNA synthesis by inhibiting DNA gyrase
Trimethoprim-sulfamethoxazole
synergistic inhibition of folic acid synthesis dose is based on trimethoprim UTI Respiratory infections (bronchitis) Ear infections MSSA or MRSA-skin/soft tissue infections
Trimethoprim-sulfamethoxazole ADE
Bone marrow suppression
Hyperkalemia
rash, fever
high incidence of adverse effects in AIDs patients
neutropenia, Stevens-Johnson syndrome and toxic epidermal necrolysis.
contraindicated in first trimester of pregnancy
Quinolones
Ciprofloxacin
Levofloxacin
inhibits DNA replication via binding to DNA gyrase (gram-negative organisms) and topoisomerase IV (gram-positive organisms)
Urogenital and GI tract infections
Ciprofloxacin and ofloxacin for urinary tract infections
Levofloxacin, gemfloxacin, and moxifloxacin are respiratory
Quinolones ADE
CNS effects (dizziness, headache)
Tendinitis due to effects on cartilage (tendon rupture)
Try to avoid in young children and pregnancy
Peripheral neuropathy
Neuromuscular-blocking activity
QTc prolongation
Oral absorption impaired by cations-Calcium, magnesium, aluminum (milk)
not with class 1a/3 antiA
Synergism
Inhibitory/killing effects of combos significantly greater than expected from their effects when used individually
check before prescribe
✓ Allergy or history of adverse drug reactions ✓ Age of patient ✓ Pregnancy ✓ Metabolic or genetic variation ✓ Renal and hepatic function: ✓ Concomitant drug therapy: ✓ Concomitant disease states
Antibiogram
report of resistance/susceptibility
local resistance patterns
for determining empiric treatment
