This protocol is NOT suitable for patients with a previous history of bronchospasm or anaphylaxis to aspirin or any of its excipients.

Aspirin is indicated in the treatment of coronary artery disease and many other cardiac disorders. Some patients are unable to receive treatment with aspirin due to a previous history of an adverse reaction to aspirin or other non-steroidal anti-inflammatory drug.

Aspirin desensitisation has been successfully used to overcome this problem and is used within many centres within the UK. This protocol is for desensitisation of cardiology patients treated within the Cardiology Directorate at Frimley Health NHS Foundation Trust. Aspirin desensitisation has been shown to be safe, however, it is possible that patients may have a reaction to aspirin.

Patients will be admitted to the cardiology ward, or ward environment in which appropriate nursing and doctor cover is available for the duration of the aspirin desensitisation.

Patient consent and a full explanation of the process must be detailed to the patient by the doctor and this must be documented in the medical notes. Reassure patient that should they have a reaction appropriate treatment will be given.

1. The patient should have intravenous access available prior to the start of the procedure.

2. Prescribe 10mg IV chlorphenamine and 100mg IV hydrocortisone in the ‘when necessary’ section of the drug chart.

3. Prescribe “Aspirin desensitisation protocol” in the ‘stat’ section of the drug chart.

4. Print page 4 of protocol and place patient details in the space.

5. Perform baseline monitoring of blood pressure, oxygen saturations and peak flow and record this on the aspirin desensitisation chart. Prior to each step repeat the above observations.

6. If there is any alteration in the patient’s condition or monitoring it should be brought to the immediate attention of the doctors.

7. If patient develops a reaction administer chlorphenamine 10mg IV and hydrocortisone 100mg IV and rechallenge at previous dose when the symptoms improve.

8. Patients with history of Samter’s triad* may additionally need Salbutamol nebulizers and oxygen if they experience respiratory symptoms during desensitisation.

9. Ensure adequate resuscitation facilities are available at all times in case of anaphylaxis.

10. As the desensitisation protocol takes 4 hours, this should not be started after 1pm.

For PPCI patients, antiplatelet therapy is at the discretion of the primary operator. For elective procedures, contact Allergy Clinic or admit for desensitisation.

Following desensitisation the patient should remain on the ward with regular monitoring. If there was no adverse reaction the patient should be prescribed regular 75mg aspirin daily from the following morning.

The importance of not missing a dose should be explained to the patient. Doses missed for more than 48hours will require a further desensitisation.

It should be clearly documented on the discharge summary that the patient has been desensitised to aspirin and for the GP to update the allergy record.

*Patients with Samter’s triad (recurrent nasal polyps, asthma, hypersensitivity to NSAIDs) should have well controlled asthma before desensitisation to aspirin with predicted FEV1 >80%

*Contact numbers for allergy consultants in order of preference: Frimley Park 03006134201, Royal Surrey 01483571122 and St. Peter’s 01932723042 (immunology) OR email rsch.allergy@nhs.net if non-urgent.

Aspirin Desensitisation Chart

Dilution:

Dissolve 300mg of dispersible aspirin tablet in 300ml of tap water for the concentration of 1mg/1ml (Solution A)

then dissolve 2mg of this dilution in 18 ml of water to make concentration 0.1mg/ml (Solution B)

1. Chapman A, Rushworth G and Leslie S. Aspirin desensitisation in patients undergoing percutaneous coronary intervention: a survey of current practice. Cardiology Journal 2013; 20; 134-138. https://journals.viamedica.pl/cardiology_journal/article/view/CJ.2013.0025/24925
2. Cortellini G, Romano A et al. Clinical approach on challenge and desensitisation procedures with aspirin in patients with ischaemic heart disease and nonsteroidal anti-inflammatory drug hypersensitivity. Allergy 2017; 72(3); 498-506.

This guideline has been registered with the Trust. However, clinical guidelines are guidelines only. The interpretation and application of clinical guidelines will remain the responsibility of the individual clinician. If in doubt, contact a senior colleague or expert. Caution is advised when using guidelines after the review date.
This guideline is for use in Frimley Health NHS Foundation Trust hospitals only. Any use outside this location will not be supported by the Trust and will be at the risk of the individual using it.

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