Penicillin-Family

Penicillin

• Penicillin G (IV)
  • Used in Strep pneumo, GAS, N meningitidis, Syphilis, Pasteurella multocida, Listeria monocytogenis, Actinomyces Israeli
• Pencillin V (oral)
  • Strep throat from GAS
• Amino penicillins (Ampi, Amox)
  • Broader gram -neg, covers enterococci
• Penicillinase-resistant penicillins IV (Methicillin, Naficillin, Oxacillin)
  • Skin infections (not MRSA)
• Pencillinase-resistant penicillins Oral (Cloxacillin, Dicloxacillin)
  • Skin infections (not MRSA)
• Antipseudomonal penicillins (Carbenicillin, Ticarcillin, Piperacillin)
  • Anaerobic and pseudomonas coverage
• Combination with beta-lactamase inhibitors (Amoxi/Clav, Ticarcillin/Clav, Ampi/sulfabactam, Pip/Tazo)
  • Broad coverage, including anaerobes, Timentin and Pip/Tazo cover pseudomonas
  • Used for hospital-acquired pneumonias

Cephalosporins

Each generation has increasing spectrum against gram negatives but less against gram positives (except fourth)

Note: MRSA and enterococci resistant to cephalopsporins

First gen (eg. cephalexin, cefazolin, cefadroxil)

• Excellent gram-positive coverage
  • Used as alternative to penicillin for staph/strep infection when penicillin allergy
  • Used before surgery as prophylaxis

Second gen (eg. cefuroxime, cefoxitin, cefotetan)

• Cefuroxime good coverage against strep pneumoniae and H influenza
  • Used for CAP, sinusitis, otitis media
• Cefotetan, cefoxitin, cefmetazole have good anaerobic coverage (bacteroides fragilis)
  • Used for intraabdominal infection, aspiration pneumonias, colorectal surgery prophylaxis

Third gen (eg. ceftriaxone, ceftazidime, cefotaxime, cefixime)

• Ceftriaxone and cefotaxime excellent CSF penetration for meninigits
  • Cefotaxime in neonates/children (ceftriaxone can interfere with bilirubin metabolism in neonates)
  • Ceftriaxone for N gonorrhea (many resistant to penicillin and tetracycline)
• Ceftazidime, cefoperazone antipseudomonal

Fourth gen (Cefepime)

• Added benefit against gram positives (and covers gram negatives like 3rd gen) and pseudomonas
• Pseudomonas (Pseudomonas coverage with Ceftazidime, Cefepime)

Fifth gen (Ceftaroline)

• Only cephalosporin with activity against MRSA

Carbapanems (Meropenem, Imipenem, Ertapenem)

• Broad coverage (except MRSA)
• Ertapenem IV once a daily
  • Drug of choice for severe diabetic foot infections (usually polymicobic)
  • Ertapenem is only carbapenem that does NOT cover pseudomonas

Monobactam (Aztreonam)

• Magic bullet for gram negative aerobic bacteria, including pseudomonas
• Used with gram positive antibiotics like Vancomycin and Clindamycin for broad-coverage

Anti-Ribosomal

Chloramphenicol

• Broad coverage, including anaerobic
  • Side effects include aplastic anemia, Gray Baby Syndrome
• Used for meningitis when severe allergy to penicillins including cephalosporins
• Young children and pregnant women who have Rocky Mountain spotted fever (cannot be treated with tetracycline)

Lincosamides (Clindamycin)

• Anaerobic, gram positive and MRSA coverage
  • Not useful against gram-negative
  • Side effects pseudomembranous colitis (C-diff)
• Used with aminoglycoside (cover gram-neg) in wound infections of the abdomen
• Female genital tract infections
  • Septic abortions
  • Alternative to metronidazole for bacterial vaginosis
• Used with beta-lactam (penicillin) or vancomycin for toxic shock syndrome with GAS or staph aureus
• Aspiration pneumonia

Oxalidinones (Linezolid)

• Gram-positive, MRSA, VRE
  • Expensive
  • Side effects Serotonin Syndrome (avoid if on antidepressants)
• Used with beta-lactam to cover hospital acquired pneumonia

Macrolides/Ketolide

Erythromycin, Azithromycin, Clarithromycin, Telithromycin (Ketolide)

• Gram-positive, some gram-negative, atypicals (Legionella, Chlamydia pneumoniae, Mycoplasma)
• Use for outpatient community-acquired pneumonia
  • Telithromycin efficacy against macrolide resistant Strep pneumo
    • Black box warning for respiratory failure in myasthenia gravis

Tetracyclines (Doxycycline)

• Chlamydia trachomatis
• Mycoplasma pneumoniae (Walking pneumonia)
• Animal/Tick-borne Bruciella and Rickettsia
• Acne
  • Side effects: Phototoxic dermatitis

Aminoglycosides

Gentamicin, Tobramycin, Amikacin (good against resistant), Neomycin (topical, as toxic)

• Break down cell walls, used with beta-lactams
• Aerobic gram-neg, Pseudomonas
  • Side effects: CN8 toxicity (Hearing loss irreversible), renal toxicity, neuromuscular blockade

Other

Fluoroquinolones

• Ciprofloxacin
  • Gram-negatives, best for Pseudomonas
  • Enterobacteriacae except anaerobes (E coli, salmonella, shigella, Campylobacter)
  • Complicated UTI, prostatitis, epididymitis
  • Gram-neg intracellular (Legionella, Burcella, Salmonella, Mycobacterium)
• Levofloxacin
  • Expanded gram-positive
  • Community acquired pneumonia, skin infections
• Moxifloxacin
  • Strep pneumo and anaerobic (intraabdominal infections)
  • Poor urinary concentration

Lipoglycopeptides (Vancomycin)

• All Gram-posiitve (MRSA, enterococcus, indwelling IV catheter resistant staph epidermidis)
  • Endocarditis (Strep/staph) in penicillin-allergic
  • Red man syndrome (rapid infusion, treat with slow infusion and antihistamine)
• Daptomycin similar to vancomycin with some side effects:
  • Monitor CPK levels (myopathy risk)
  • Eosinophilic pneumonia (stop dapto and give steroids)

Sulfonamides (TMP SMX)

• Gram positive, gram negative, some protozoans (Pneumocystis carinii, Toxoplasma gondii, Isospora belli)
  • Increases INR
• T (Resp Tree): Otitis media, sinusitis, bronchitis, pneumonia
• M (Mouth): Shigella, Salmonella, E coli
• P (Pee): UTI, prostatitis, urethritis
• S (AIDS): PCP prophylaxis

Bug Coverage

Pseudomonas Aeruginosa

• Penicillins (Ticarcillin, Ticarcillin/Clav, Piperacillin, Pip/Tazo)
• Third gen cephalosporins (Ceftazidime)
• Fourth gen cephalosporins (Cefepime)
• Carbapenems (Imipenem, Meropenem, Doripenem)
• Aztreonam
• Ciprofloxacin
• Aminoglycosides (Amikacin, Gentamicin, Tobramycin)
• Polymixins

Anaerobes (Bacteroides Fragilis)

• Penicillins with beta-lactamase inhibitor (Amoxi/Clav, Ticarcillin/Clav, Ampi/subactam, Pip/Tazo)
• Second gen cephalosporins (Cefoxitin, Cefotetan, Cefmetazole)
• Carbapenems (Imipenem, Meropenem, Doripenem, Ertapenem)
• Chloramphenicol
• Clindamycin
• Metronidazole
• Moxifloxacine
• Tigecycline

Atypical (Mycoplasma pneumoniae, Chlamydia pneumoniae, Legionella)

• Fluoroquinolone (levofloxacin, moxifloxacin)
• Macrolide (erythromycin, azithromycin)
• Doxycycline

MRSA

• Vancomycin
• Linezolin
• Daptomycin
• Quinupristin/dalfopristin
• Tigecycline
• Ceftaroline
• Clindamycin
• TMP/SMX
• Tetracycline (Doxycycline/Minocycline)

VRE

• Linezolid
• Daptomycin
• Tigecycline

C-diff

• Oral vancomycin (or metronidazole)

"No Tazo"

• SPACE (Serratia, Pseudomonas, Acinetobacter, Citrobacter, and Enterobacter) infections (inducible β-lactamase AmpC)
  • Avoid Tazo as 30% treatment failure
  • Use Cipro/Carbapenem

Penicillin Allergy

• 85% of "penicillin-allergic" will tolerate penicillin
  • High-risk: Resp distress, angioedema within one hour
  • Low-risk : >10 years ago (most lose IgE), do not remember
    • Skin-test, then if negative penicillin challenge, then allergy ruled out
• Aztreonam is only monobactam with no reactivity with penicillin
  • Consider in Type I immediate hypersensitivity
  • Consider desensitization
• Otherwise, if no Type I allergy, avoid specific implicated drug (may consider skin-test + graded challenge)
  • Cephalosporin (2% cross-reactivity with penicillin skin test-positive)
    • If allergy to cephalosporin, avoid same R group side chain cephalosporins
  • Carbapenem (<1% will not tolerate despite skin-test positiive)

Fluoroquinolone Allergy

• If history of anaphylaxis reaction to one fluoroquinolone, avoid entire class
• For delayed on-set maculopapular nonpruritic rash, may consider graded challenge of another fluoroquinolone

Vancomycin Allergy

• Avoid if bullous reaction or thrombocytopenia
• If Red Man Syndrome (flushing, pruritus, urticaria), premedicate with antihistamine (diphenhydramine) and acetaminophen, hold opiates if possible, and infuse slower (eg. half rate, or 1g over >100 mins)