Drugs for Rhinitis and Rhinorrhoea Flashcards
(47 cards)
What is rhinitis?
A common and often debilitating disease involving acute or chronic inflammation of the nasal mucosa
What are the characteristic symptoms of rhinitis?
- 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)
What is nasal congestion?
Does NOT refer to mucous - refers to dilated blood vessels in respiratory or nasal mucosa
* These dilated blood vessels contribute to swelling of mucosa and lead to obstruction of airflow through nasal cavity
What are the different types of rhinitis?
- Allergic
- Non-allergic
- Mixed
What are the classifications of allergic rhinitis?
- Seasonal (SAR)
- Perennial (PAR)
- Episodic (EAR)
What condition is allergic rhinitis often linked to?
Asthma
What is the mechanism of allergic rhinitis?
- Inhalation of allergen increases specific 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, cysLTs, tryptase, prostaglandins
- Causes acute itching, sneezing, rhinorrhoea and nasal congestion
- Delayed response caused by recruitment of lymphocytes and eosinophils to nasal mucosa causes congestion and obstruction
What is non-allergic rhinitis?
Any rhinitis, acute, or chronic, that does not involve IgE-dependent events
What are causes of non-allergic rhinitis?
- 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)
What is occupational rhinitis?
May involve both allergic and non-allergic components
What do both rhinitis and rhinorrhoea?
- Involve increased mucosal blood flow
- Increased blood vessel permeability
- These effects increase the volume of the nasal mucosa and cause difficulty breathing in
What is used to target inflammation in rhinitis?
Glucocorticoids (anti-inflammatory) - will treat allergic rhinitis
What drugs are used to block mediator receptors in rhinitis and rhinorrhoea?
- H1 (histamine) receptor antagonists
* CysLT1 receptor antagonists
What drugs are used to decrease nasal blood flow?
Vasoconstrictors (act on a1 adrenoceptors)
What drugs are anti-allergic in the treatment of rhinitis?
Sodium cromoglicate (immunosuppressant effect)
What is the purpose of a decongestant?
Does not get rid of mucous in the nose, restricts blood flow to vasal mucosa
What is the mechanism of glucocorticoids?
Reduce vascular permeability, recruitment and activity of inflammatory cells and the release of cytokines and mediators
What are glucocorticoids used to treat?
- Mainstay therapy for SAR and PAR
* Also used in NARES and vasomotor rhinitis
How are glucocorticoids administered in rhinitis?
Applies topically as a spray to the nasal mucosa e.g. intranasal administration once daily
How are glucocorticoids used to treat moderate-to-severe and severe intractable rhinitis?
- Moderate-to-severe - may be combined with anti-histamines
* Severe - may be given orally (short term)
What are examples of glucocorticoids?
- beclometasone
- fluticasone
- prednisolone (oral)
What are anti-histamines?
H1 receptor antagonists
What is the mechanism of H1 receptor antagonists?
- Competitive antagonists that reduce effects of mast cell derived histamine
- Less effect on congestion than other symptoms
What effects does histamine normally have?
- vasodilatation and increased capillary permeability
- activation of sensory nerves
- mucus secretion from submucosal glands
