Penicillin desensitisation protocols for adults

Consider whether penicillin desensitisation is appropriate; see Patient appropriateness for antimicrobial desensitisation. For most patients who report a penicillin allergy, allergy assessment and allergy testing is all that is required.

If penicillin desensitisation is required, organisational oversight to ensure patient safety is necessary. Key requirements for antimicrobial desensitisation programs are listed in Key requirements for antimicrobial desensitisation programs.

Penicillin desensitisation is usually performed with the antibiotic needed for treatment; however, phenoxymethylpenicillin can be used to desensitise to benzylpenicillin, and amoxicillin can be used to desensitise to ampicillin.

In these guidelines, penicillin desensitisation protocols for adults are provided for:

• oral amoxicillin and phenoxymethylpenicillin – see Oral penicillin desensitisation protocol for adults
• benzylpenicillin – see Oral penicillin desensitisation protocol for adults or Intravenous penicillin desensitisation protocol for adults.

There are limited data on penicillin desensitisation in children. In many cases, the protocols are extrapolated from protocols used in adult patientsCaimmi 2019Cernadas 2013Diaferio 2020Norton 2018. If penicillin desensitisation is necessary, seek expert advice from a paediatric allergist.

Desensitisation protocols for penicillins usually start with a dose of approximately 1/1000 to 1/10 000 of the therapeutic dose (ie for a 1000 mg dose, start with 1 to 0.1 mg). Doses are typically doubled with each step of the protocol, and administered at 15- to 30-minute intervals until the therapeutic dose is achieved. In most cases, the desensitisation can be completed in 4 to 12 hoursBroyles 2020.