Antimicrobial Stewardship (AMS)

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

Antimicrobial Dosing 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