Pharmacology of Rhinitis

Question 1

Describe Rhinitis?

Answer 1

rhinorrohea (‘runny nose’ - watery mucus accumulation in nasal cavity)
sneezing
itching
nasal congestion and obstruction (swelling of nasal mucosa largely due to dilated blood vessels - particularly in cavernous sinusoids)

Question 2

What 3 classes can Rhinitis be?

Answer 2

allergic
non-allergic
mixed

Question 3

What 3 ways can allergic rhinitis be?

Answer 3

• seasonal (SAR)
• perennial (PAR)
• episodic (EAR)

Question 4

How does allergic rhinitis occur?

Answer 4

• inhalation of allergen increases IgE levels
• IgE binds to receptors on mast cells and basophils
• Re-exposure to allergen causes mast cell and basophil degranulation
• release of mediators including histamine and tryptase which causes symptoms of sneezing etc
• delayed response caused by the recruitment of lymphocytes and eosinophils to nasal mucosa causes congestion

Question 5

What is non allergic rhinitis?

Answer 5

any rhinitis, acute, or chronic, that does not involve IgE–dependent events – causes are diverse and include:
•Infection – infectious rhinitis (largely viral)
•hormonal imbalance – hormonal rhinitis (e.g. pregnancy)
•vasomotor disturbances – vasomotor rhinitis (cause unknown, i.e. idiopathic)
•Nonallergic rhinitis with eosinophilia syndrome (NARES)
•Medications – drug induced rhinitis (e.g. aspirin)

Question 6

What is the treatment for the inflammation caused by rhinitis?

Answer 6

glucocorticoids

• beclometasone
• fluticasone
• prednisolone

Question 7

What is the treatment to block the mediator receptor in rhinitis?

Answer 7

Anti histamine - H1 receptor antagonists
-loratidine
-fexofenadine
-cetirizine
CysLT1 receptor antagonists
-Montelukast

Question 8

What is the treatment for the increased nasal blood flow in rhinitis?

Answer 8

Vasoconstrictors

Oxymetazoline - a selective a1-adrenoceptor agonist

Question 9

What is the treatment to prevent allergy in rhinitis?

Answer 9

Sodium Cromoglicate