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Table 1 Medication washout periods

From: Clinical validation of controlled exposure to house dust mite in the environmental exposure unit (EEU)

Medication Washout period
Beta-blockers, alpha-adrenoceptor blockers Not permitted
Topical alpha-adrenergic agonists 48 h
Short-Acting Antihistamines (e.g. Diphenhydramine) *3 days
Anti-allergic eye drops (ocular antihistamines, decongestants and cromoglycates) 5 days
Long-Acting Antihistamines (e.g. fexofenadine, loratadine, cetirizine)–note that H2 antagonists (e.g. Zantac, ranitidine) are not considered antihistamines for the purposes of this study *5 days
Anticholinergics 7 days
Topical Corticosteroids (except 1% or less of hydrocortisone) 7 days
Intranasal or inhaled corticosteroids (e.g. triamcinolone acetonide, fluticasone) **14 days
Intranasal or inhaled cromolyn 14 days
Leukotriene inhibitors 14 days
Tricyclic Antidepressants and Monoamine oxidase inhibitors 14 days
Systemic corticosteroids (oral) 30 days
Depot corticosteroids 60 days
Biologics 6 months
  1. *Prior to skin prick testing and screening nasal brushing
  2. **Prior to screening nasal brushing