Week 2.08 Anti Allergic And Anti-inflammatory Flashcards
What are the ocular side effects of histamine
Within 20-30mins they may get these side effects:
- itching
- blood vessel dilation
- increased blood vessel permeability
After 5-10hrs - secondary response as the inflammatory mediators arrive
What type of drugs can we use to stop this process happening
Mast cell stabilisers
Antihistamines
Topical ocular decongestants
What do mast cell stabilisers do
- Prevent mast cells from degranulating (release of inflammatory mediators)
- Stops further release of inflammatory mediators
- No effect on histamine already released
Useful for longer term allergic eye conditions - most effective when used prophylactically (preventative measure) so if px knows they are going to be in contact with allergen they should start 2 weeks before
What’s the difference between seasonal and perennial allergic conjunctivitis
Seasonal: hay fever
- flare up certain times of year
- 90% px
Perennial: non season allergen
- there all year around - might be animal or dust mites
- 5% of px
- some meds taken all year around
What are sone signs and symptoms of allergic conjunctivitis
Sxs:
- bilateral
- itchy
- redness
- watery
Signs:
- mild eyelid oedema
- conj hyperaemia
- conj chemosis
What’s the main mast cell stabilisers we use
Sodium cromoglicate - opticrom
All optoms have access
- available as general sales list product
Only licensed for seasonal allergic conjunctivitis (hay fever)
Takes 2 weeks to work
Not for use in under 6yrs
What can sodium cromoglicate POM version also be used for
Contact lens associated papillary conjunctivitis
What is an alternative to sodium cromoglicate
Nedocromil sodium
Antihistamines
Good at treating sxs there and then
Antagonistic activity at histamine receptor sites
Blocks histamine from activating its receptors
Can be used for both seasonal and perennial allergic conjunctivitis
What is a sedating systemic antihistamine
Older class of drugs: may induce drowsiness
Cautions: driving
Ocular side effects: mydriasis
Piriton: chlorphenamine
Non sedating systemic antihistamines
- newer class of drugs; less likely to cause drowsiness
Cetirizine - GSL
When would we use topical antihistamines
Seasonal and perennial allergic conjunctivitis
IP only
May be used in combination with mast cells stabiliser - antihistamine provides rapid relief whilst mast stabiliser becomes effective
POM
E.g. azelastine, emedastine, olopatadine
What are topical ocular decongestants
Adrenergic alpha agonists
Mimics action of sympathetic branch of ANS
Reduces conj hyperaemia
Provide temp relief from mild eyelid irritation
Cautions and side effects of topical ocular decongestants
May produce rebound reaction
Known as conjunctival medicamentosa:
- toxic effects of eye drops
- delayed hypersensitivity to eye drops
Conjunctival hyperaemia is exacerbated, rather than reduced
What does NSAID stand for
Non-steroidal anti inflammatory drug
What are the two forms of cox enzyme
- COX-1: normal processes in uninflamed tissues
a. Stomach acid levels
b. Gastric protection - COX-2: synthesis of prostaglandins in inflamed tissues
Many NSAIDs are non selective – just gonna knock out both types of COX
Therefore inhibition of COX-1 has the potential to cause gastro-intestinal side (e.g. nausea, stomach ulcers, peptic bleeding)
What are the three major properties of NSAID
o Anti-inflammatory (control inflammatory response)
o Analgesic (relief of pain)
o Anti-pyretic (control fever)
Examples of systemic NSAIDs
Ibuprofen
Aspirin
Diclofenac sodium
Naproxen
May use systemic NSAIDs to manage mild to moderate pain (e.g. corneal abrasions)
Topical ocular NSAIDs
Greater therapeutic effect on ocular region
Reduced risk of systemic side effects
Used to treat:
- corneal abrasion
- season allergic conjunctivitis
- episcleritis
What are some topical ocular NSAIDs that are POMs
- Diclofenac sodium
- Flurbiprofen
- Kerorolac
What is the mode of action of corticosteroids
Inhibits the release of phospholipids A2 enzyme
What do corticosteroids do
Used to control inflammation
Reduce sensation of pain
Scleritis
Anterior uveitis
Allergic conjunctivitis
Ocular surgery
Dosing of corticosteroids
Initially intensive
Reduce to normal theraputic dose
Abrupt cessation causes rebound effect
What are some examples of corticosteroids
Prednisolone
Dexamthasone
Fluromethalone
Betamethasone
-“one”
