Penicillin Allergy

All drug allergies must be documented on the medication chart, with the patient’s reaction

  • The diagnosis of penicillin allergy is often accepted without obtaining a detailed history of the patient’s reaction. As a result, penicillins may unnecessarily be withheld from some patients who do not have a true allergy. This may adversely affect their clinical outcome.   

  • The clinical symptoms of a true Type I allergy to penicillin are urticaria, laryngeal oedema, bronchospasm, hypotension, or local swelling within 72 hours of administration or development of a pruritic rash even after 72 hours. These patients should not receive a penicillin.

  • Patients with a history of intolerance to penicillin e.g. Gastro-intestinal upset, after administration are probably not truly allergic to penicillin.       

  • The frequently cited figure of 10% cross reactivity between penicillins and cephalosporins is thought to be an overestimate.  The true incidence of cross-sensitivity is uncertain. It is thought that first generation cephalosporins have a greater risk of cross-sensitivity than second or third generation cephalosporins.

  • Patients with Type I allergy should avoid cephalosporins and other beta-lactam antibiotics for non-severe infections if a suitable alternative exists.  In life threatening infections, when the use of a non beta-lactam antibiotic would be sub-optimal, consideration can be given to a second or third generation cephalosporin or meropenem under close observation.  Seek advice from Microbiology. 

 

Antibiotics to be avoided in Type I
Penicillin allergy

Amoxicillin                

• Benzylpenicillin      

• Co-amoxiclav (Augmentin®)

• Flucloxacillin

• Phenoxymethylpenicillin (penicillin V)

• Piperacillin + tazobactam (Tazocin®)

• Temocillin

 

Antibiotics to be avoided or used with
caution in 
Type I Penicillin allergy

Cephalosporins: 

 •  Cefixime                  •  Ceftazidime        

 •  Ceftriaxone             •  Cefuroxime

 •  Cefotaxime             

 Other beta-lactam antibiotics:

 •  Aztreonam

 •  Meropenem

 •  Ertapenem

 

Antibiotics that are safe to use in 

Type I penicillin allergy

•  Amikacin                  •  Linezolid    

•  Ciprofloxacin            •  Metronidazole

•  Clarithromycin         •  Nitrofurantoin

•  Clindamycin             •  Rifampicin

•  Colistin                     •  Sodium Fusidate    

•  Co-trimoxazole        •  Teicoplanin

•  Doxycycline             •  Tetracycline

•  Erythromycin           •  Tobramycin

•  Fosfomycin              •  Trimethoprim

•  Gentamicin              •   Vancomycin

•  Levofloxacin