Antimicrobial Stewardship (AMS)

Resources to help you ensure the safe and effective use of antimicrobials in NSHA patients.

Antimicrobial Dosing

Please refer to Firstline for antimicrobial dosing recommendations.

Drug Bug Chart

IV/PO Step Down Policy

Beta-Lactam Allergy

​Beta-lactam Allergy Assessment and Management

  • Do not avoid all beta-lactams in patients reporting penicillin allergies.

    • Penicillin allergy is over reported and cross-allergy between penicillins and cephalosporins is overestimated

  • ​Beta-lactams include all penicillins (i.e. penicillin, ampicillin, amoxicillin, cloxacillin, piperacillin, etc.) including those combined with beta-lactamase inhibitors (amoxicillin/clavulanate, piperacillin/tazobactam), cephalosporins, and carbapenems.
  • The incidence of a true IgE mediated hypersensitivity reaction to a beta-lactam is
    • 1 to 5 per 10,000 treatment courses for penicillins
    • 0.1 to 100 per 100,000 for cephalosporins
    • Individuals with IgE mediated allergies are 3 times more likely to have de novo allergies to unrelated medications. 
  • Patients with a history suggestive of a serious or life-threatening non-IgE mediated reaction to ANY beta-lactam (e.g. Stevens-Johnson syndrome, toxic epidermal necrolysis, drug reaction with eosinophilia and systemic symptoms, acute generalized exanthematous pustulosis, hemolytic anemia, interstitial nephritis, hepatitis, serum sickness), should AVOID all beta-lactams. 
  • Penicillin, amoxicillin, and 1st generation cephalosporins are safe, effective, and inexpensive antibiotics.
    • Unnecessarily avoiding their use can result in therapy that is
      • less effective
      • more toxic
      • associated with greater risk of developing antibiotic resistant microorganisms
      • more costly
  • Since many people mistakenly attribute an adverse drug reaction to an allergy, it is important to clarify whether a reaction is
    • an IgE mediated hypersensitivity reaction
    • a non-IgE mediated hypersensitivity reaction
      • non-serious reaction
      • serious or life-threatening
        • e.g. Stevens-Johnson syndrome, toxic epidermal necrolysis (TEN), drug reaction with eosinophilia and systemic symptoms, erythema multiforme
    • a non-hypersensitivity drug-related adverse effect (e.g. GI complications, headache, yeast infections, isolated itch). 

Table 1: Onset, symptoms, and management options for various beta-lactam associated reactions

Reaction Onset Symptoms Management options

Hypersensitivity

  • IgE mediated

Usually <1 hour

(max 72 hours)

Anaphylaxis, urticaria, angioedema, laryngeal edema, wheeze, hypotension

Do not give the same drug again. Choose another cephalosporin with a different side chain.

Do not give another penicillin if culprit was a penicillin.

  • Non-IgE mediated1
>72 hours

Non-serious2

Contact dermatitis, pruritic maculopapular eruption

Not a contraindication to using a beta-lactam. Consider provocation challenge or an antibiotic with a different side chain.
    Serious or life-threatening3 AVOID all beta-lactams
Non-hypersensitivity Anytime Gastrointestinal symptoms, flushing during infusion, headache, yeast infection, isolated itch Not a contraindication to using a beta lactam

1Skin testing has no role in the diagnosis of non-IgE mediated reactions.

2>90% of rashes occurring after people take penicillin (amoxicillin) are mild non-IgE reactions. Rashes occur in up to 7% of people.

3Serious or life-threatening non-IgE mediated hypersensitivity reactions are rare with beta-lactams. They include Stevens-Johnson syndrome, topix epidermal necrolysis, drug reaction with eosinophilia and systemic symptoms, acute generalized exanthematous pustulosis, hemolytic anemia, interstitial nephritis, hepatitis, and serum sickness. 

Last reviewed August 2020

Provocation Challenge

  • Give 10% of a therapeutic dose under observation
  • 30 minutes later, give remaining 90% of therapeutic dose
  • Observe for 1 hour after last dose.

Last reviewed August 2020

  • Cross-reactivity risk between penicillin and cephalosporins is low.
    • For IgE-mediated allergies, the cross reaction between penicillin and cephalosporins is mediated by similarities of the specific chemical side chains of penicillin and cephalosporins, rather than the beta-lactam ring. See cross-reaction chart.
    • Beta-lactams with different side chains may be considered in those with a history of an IgE-mediated reaction.
    • This consideration is based on theoretical risk and studies using this approach are not yet available. 
  • If unable to rule in or rule out an IgE-mediated allergy, referral to an allergist is recommended. 

Last reviewed August 2020

Cefazolin for Surgical Prophylaxis in Patients with a Beta-lactam Allergy

Cefazolin is the drug of choice for surgical prophylaxis

  • Cefazolin is more effective than alternatives like clindamycin and vancomycin for reducing surgical site infections.
  • Cefazolin is a safe medication with less toxicities than clindamycin and vancomycin.
  • Cefazolin can be administered quickly prior to incision.

Can patients with a beta-lactam allergy receive cefazolin safely?

  • Cefazolin has a unique side chain. Since side chain similarities are responsible for IgE-mediated (anaphylaxis) cross-reactions, cefazolin does not cross-react with other beta-lactams.
  • Cefazolin for surgical prophylaxis is given in a monitored preoperative setting. 
  • Cefazolin should be avoided if
    • History suggestive of a serious or life-threatening non-IgE-mediated reation to beta-lactams (e.g. Stevens-Johnson syndrome, toxic epidermal necrolysis, drug reaction with eosinophilia and systemic symptoms, acute generalized exanthematous pustulosis, hemolytic anemia, interstitial nephritis, hepatitis, serum sickness)
    • Anaphylaxis to cefazolin specifically

Last reviewed August 2020