Updated: 7/23/2017

Cephalosporins

Topic
Review Topic
0
0
Questions
1
0
0
Introduction
  • Classification
    • antibiotic
      • penicillin-family (β-lactam)
        • cephalosporins
  • Drugs
    • 1st generation
      • cefazolin
      • cephalexin
    • 2nd generation
      • cefoxitin
      • cefaclor
      • cefuroxime
    • 3rd generation
      • ceftriaxone
      • cefotaxime
      • ceftazidime
      • cefixime
    • 4th generation
      • cefepime
    • 5th generation
      • ceftaroline
Mechanism
  • Action 
    • bactericidal
    • see Penicillin 
    • β-lactam ring is less susceptible to penicillinases (β-lactamases)
    • additional R groups allow manipulation to produce multiple drugs
  • Resistance
    • see Penicillin 
    • MRSA is resistant to all cephalosporins
      • via modified penicillin-binding protein (PBP)
    • Enterococci (group D strep) are resistant to all cephalosporins
Uses
  • Rule of thumb
    • lower generations favor Gram-positive coverage
    • higher generations favor Gram-negative coverage
      • except 4th generation which has extended Gram-positive coverage
  • 1st generation
    • Gram-positives
    • some Gram-negatives
      • E. coli
      • Proteus
      • Klebsiella
    • given prophylactically against skin infections
  • 2nd generation
    • Gram-positives
    • more Gram-negatives
      • Haemophilus influenzae
      • Neisseria spp.
      • Serratia marcescens
      • Proteus mirabilis
      • E. coli
      • Klebsiella pneumoniae
      • Enterobacter aerogenes
    • Anaerobes
  • 3rd generation
    • serious Gram-negative infections
      • including Pseudomonas (use ceftazidime)
    • gonorrhea
      • use ceftriaxone 
    • meningitis
      • use ceftriaxone
      • most cephalosporins penetrate BBB
    • pyelonephritis
    • pneumonia
  • 4th generation (cefepime)
    • Pseudomonas
    • improved activity against Gram-positive organisms
  • 5th generation (ceftaroline)
    • broad Gram-positive and Gram-negative coverage
    • covers MRSA (non-inferior to vancomycin)
    • does not cover Pseudomonas or anaerobes
Adverse effects
  • Allergy
    • 5-10% of patients with penicillin allergy are also allergic to cephalosporins
    • IgE mediated
    • rash can appear weeks later
  • nephrotoxicity of aminoglycosides
  • Superinfection
    • e.g. C. difficile
  • MTT side chain (methyl-thio-tetrazole) side chain cephalosporins are associated with specific adverse effects
    • disulfiram (Antabuse)-like reaction with ethanol
      • can interfere with metabolism of alcohol
      • acetaldehyde accumulates
      • results in nausea and vomiting
    • interferes with synthesis of Vitamin K-dependent clotting factors
    • seen with
      • cefamandole
      • cefmetazole
      • cefotetan
 

Please rate topic.

Average 5.0 of 4 Ratings

Thank you for rating! Please vote below and help us build the most advanced adaptive learning platform in medicine

The complexity of this topic is appropriate for?
How important is this topic for board examinations?
How important is this topic for clinical practice?
Questions (1)
Lab Values
Blood, Plasma, Serum Reference Range
ALT 8-20 U/L
Amylase, serum 25-125 U/L
AST 8-20 U/L
Bilirubin, serum (adult) Total // Direct 0.1-1.0 mg/dL // 0.0-0.3 mg/dL
Calcium, serum (Ca2+) 8.4-10.2 mg/dL
Cholesterol, serum Rec: < 200 mg/dL
Cortisol, serum 0800 h: 5-23 μg/dL //1600 h:
3-15 μg/dL
2000 h: ≤ 50% of 0800 h
Creatine kinase, serum Male: 25-90 U/L
Female: 10-70 U/L
Creatinine, serum 0.6-1.2 mg/dL
Electrolytes, serum  
Sodium (Na+) 136-145 mEq/L
Chloride (Cl-) 95-105 mEq/L
Potassium (K+) 3.5-5.0 mEq/L
Bicarbonate (HCO3-) 22-28 mEq/L
Magnesium (Mg2+) 1.5-2.0 mEq/L
Estriol, total, serum (in pregnancy)  
24-28 wks // 32-36 wks 30-170 ng/mL // 60-280 ng/mL
28-32 wk // 36-40 wks 40-220 ng/mL // 80-350 ng/mL
Ferritin, serum Male: 15-200 ng/mL
Female: 12-150 ng/mL
Follicle-stimulating hormone, serum/plasma Male: 4-25 mIU/mL
Female: premenopause: 4-30 mIU/mL
midcycle peak: 10-90 mIU/mL
postmenopause: 40-250
pH 7.35-7.45
PCO2 33-45 mmHg
PO2 75-105 mmHg
Glucose, serum Fasting: 70-110 mg/dL
2-h postprandial:<120 mg/dL
Growth hormone - arginine stimulation Fasting: <5 ng/mL
Provocative stimuli: > 7ng/mL
Immunoglobulins, serum  
IgA 76-390 mg/dL
IgE 0-380 IU/mL
IgG 650-1500 mg/dL
IgM 40-345 mg/dL
Iron 50-170 μg/dL
Lactate dehydrogenase, serum 45-90 U/L
Luteinizing hormone, serum/plasma Male: 6-23 mIU/mL
Female: follicular phase: 5-30 mIU/mL
midcycle: 75-150 mIU/mL
postmenopause 30-200 mIU/mL
Osmolality, serum 275-295 mOsmol/kd H2O
Parathyroid hormone, serume, N-terminal 230-630 pg/mL
Phosphatase (alkaline), serum (p-NPP at 30° C) 20-70 U/L
Phosphorus (inorganic), serum 3.0-4.5 mg/dL
Prolactin, serum (hPRL) < 20 ng/mL
Proteins, serum  
Total (recumbent) 6.0-7.8 g/dL
Albumin 3.5-5.5 g/dL
Globulin 2.3-3.5 g/dL
Thyroid-stimulating hormone, serum or plasma .5-5.0 μU/mL
Thyroidal iodine (123I) uptake 8%-30% of administered dose/24h
Thyroxine (T4), serum 5-12 μg/dL
Triglycerides, serum 35-160 mg/dL
Triiodothyronine (T3), serum (RIA) 115-190 ng/dL
Triiodothyronine (T3) resin uptake 25%-35%
Urea nitrogen, serum 7-18 mg/dL
Uric acid, serum 3.0-8.2 mg/dL
Hematologic Reference Range
Bleeding time 2-7 minutes
Erythrocyte count Male: 4.3-5.9 million/mm3
Female: 3.5-5.5 million mm3
Erythrocyte sedimentation rate (Westergren) Male: 0-15 mm/h
Female: 0-20 mm/h
Hematocrit Male: 41%-53%
Female: 36%-46%
Hemoglobin A1c ≤ 6 %
Hemoglobin, blood Male: 13.5-17.5 g/dL
Female: 12.0-16.0 g/dL
Hemoglobin, plasma 1-4 mg/dL
Leukocyte count and differential  
Leukocyte count 4,500-11,000/mm3
Segmented neutrophils 54%-62%
Bands 3%-5%
Eosinophils 1%-3%
Basophils 0%-0.75%
Lymphocytes 25%-33%
Monocytes 3%-7%
Mean corpuscular hemoglobin 25.4-34.6 pg/cell
Mean corpuscular hemoglobin concentration 31%-36% Hb/cell
Mean corpuscular volume 80-100 μm3
Partial thromboplastin time (activated) 25-40 seconds
Platelet count 150,000-400,000/mm3
Prothrombin time 11-15 seconds
Reticulocyte count 0.5%-1.5% of red cells
Thrombin time < 2 seconds deviation from control
Volume  
Plasma Male: 25-43 mL/kg
Female: 28-45 mL/kg
Red cell Male: 20-36 mL/kg
Female: 19-31 mL/kg
Cerebrospinal Fluid Reference Range
Cell count 0-5/mm3
Chloride 118-132 mEq/L
Gamma globulin 3%-12% total proteins
Glucose 40-70 mg/dL
Pressure 70-180 mm H2O
Proteins, total < 40 mg/dL
Sweat Reference Range
Chloride 0-35 mmol/L
Urine  
Calcium 100-300 mg/24 h
Chloride Varies with intake
Creatinine clearance Male: 97-137 mL/min
Female: 88-128 mL/min
Estriol, total (in pregnancy)  
30 wks 6-18 mg/24 h
35 wks 9-28 mg/24 h
40 wks 13-42 mg/24 h
17-Hydroxycorticosteroids Male: 3.0-10.0 mg/24 h
Female: 2.0-8.0 mg/24 h
17-Ketosteroids, total Male: 8-20 mg/24 h
Female: 6-15 mg/24 h
Osmolality 50-1400 mOsmol/kg H2O
Oxalate 8-40 μg/mL
Potassium Varies with diet
Proteins, total < 150 mg/24 h
Sodium Varies with diet
Uric acid Varies with diet
Body Mass Index (BMI) Adult: 19-25 kg/m2
Calculator

Question locked
Sorry, this question is for
PEAK Premium Subscribers only
Upgrade to PEAK
Topic COMMENTS (10)
Private Note