The evaluation of the patient is done based on the kinetics of drug administration, to allow for drug absorption and distribution. A drug administered IV required evaluation within minutes of administration, while a drug administered orally might be evaluated between 15-30 minutes after administration.
Criteria - both of the following:
(1) clinical findings consistent with histamine effect
(2) elevation in plasma histamine levels (> 1 ng/mL)
Clinical findings:
(1) tachycardia and hypotension (in excess of the pharmacologic effect of the drug)
(2) erythema, wheals, and/or urticaria
(3) laryngeal and/or nasal symptoms (stuffy nose, sneezing, cough, throat constriction)
where:
• The assay method and normal reference range for the histamine assay were not listed.
• An alternative to criteria for histamine release would be a change in the post-exposure sample vs the pre-exposure sample.
• Mast cell degranulation can release other vasoactive compounds.
• Duda et al used the term histamine release reaction for the clinical findings not associated with an elevation in plasma histamine.
