Allergy Rhinitis: Antihistamines Flashcards
What is allergy rhinitis?
Symptomatic disorder of nose resulting from an IgE-mediated immunological reaction following exposure to allergen
What are the main symptoms?
Rhinorrhoea = runny nose
Nasal itching
Congestion
Sneezing
What are some diagnostic tests?
Rhinoscopy
Allergy tests
Cytology of nasal secretions
CT scan
What will it look like upon examination?
Red or irritated nose
Blocked nose
Clear mucus present
Sinuses tender
Eyes may appear red
How can you treat it?
Avoid allergen - eg. hay fever = stay indoors, check pollen count
Pharmacotherapy
What is part of pharmacotherapy?
Mast cell stabilisers
Steroids
Antihistamines
What does sodium cromoglicate do?
MUST be used before cells burst = NO symptoms
Stabilise mast cells
= decrease histamine release from mast cells
+ decrease release of other inflammatory agents
How is sodium cromoglicate given?
As eye drops:
OTC
1 drop in each eye
Formulation seeps into nasal cavity
Describe beclomethasone
Corticosteroid
Aqueous nasal spray
Can cause rebound congestion
How is beclomethasone used?
2 sprays each morning + night
Blow nose before use to clear mucus
ONLY used for 3 months
What are 1st generation H1 receptor antagonists?
“Sedating antihistamines”
Diphenhydramine, chlorphenamine
What are 2nd generation H1 receptor antagonists?
“Non-drowsy”
Loratidine, cetirizine
What are the other uses of H1 anatgonists?
Sedating, antiemetic + vertigo
What are the properties of 1st generation H1 antagonists?
Lipid soluble = cross BBB
Well absorbed
Metabolised in liver
t1/2 = 5-6hrs
What are the adverse reactions of 1st generation H1 antagonists?
Sedation, drowsiness
Headache, nausea, vomiting
Cough
Anti-muscarinic effects
