Anti Allergic Drugs

ANTI-ALLERGIC DRUGS

ALLERGIC CONJUNCTIVITIS It is the inflammation of conjunctiva due

to reaction from allergy causing substances like pollen, dander , house dust e.t.c

Clinical classification Acute Allergic Conjunctivitis (AAC) Intermittent/Seasonal Allergic

Conjunctivitis (IAC/SAC) Persistent/Perennial Allergic

Conjunctivitis (PAC) Giant Papillary Conjunctivitis (GPC) Vernal Keratoconjunctivitis (VKC) Atopic Keratoconjunctivitis (AKC)

The milder forms of allergic eye diseases have fluctuating symptoms of itching, tearing, and swelling.

Chronic form of the disease give rise, in addition, to more severe symptoms including pain, visual loss from corneal scarring, cataract or glaucoma, and disfiguring skin and lid changes.

NON PHARMACOLOGICAL APPROACH Allergen avoidance including physical

barriers, eg, hat, sunglasses, allergen-impermeable pillow and mattress covers

Cold compresses

Preservative-free tears

Slide 6Modes and sites of action of allergic conjunctivitis therapies

Mast cell

B cell

T cell(mast cell) Eosinophil

IL-4

IL-3, -5

GM-CSF

VCAM-1

IgE

Immediate symptoms• Itch, redness, edema,chemotaxis, edema, vascular permeability•Sensitized nerves, enhanced pain, edema, redness

Chronic symptoms•cell destruction•disruption of ocular surface

HistamineLeukotrienesProstaglandins

Allergen

Allergen

avoidance

Immuno-therapy

AntihistaminesOlopatadine

Sodium cromoglycateOlopatadine

Steroids

Eosinophil and Neutrophil chemotactic factors:

Anti-IgE

ANTIHISTAMINICS Used during acute attacks

Topical antihistamines

Azelastine 0.05%, emedastine0.05%, levocabastine0.05% used 4 times a day

Topical antihistamine plus vasoconstrictor

antazoline-naphazoline , cetirizine-pseudoephedrine , pheniramine-naphazoline

Oral antihistamines - Less effective than topical therapies - unwanted effects of ‘dry eye’ - indicated for multiple allergic symptomatology - non-sedating oral antihistamines:

loratadine, fexofenadine, cetirizine

Side efffects Headache – most common Bad taste Blurred vision Burning or stinging Corneal infiltrates Dry eye Rhinitis sinusitis

Mast cell stabilizers They produce stabilization of mast cell

membrane & prevent its degranulation Takes days to weeks to reach its peak

efficacy – so not used in acute attacks Can be used for prophylaxsis

Disodium cromoglycolate 4% : QID

Nedocromil 2% : Twice daily

Lodoxamide 0.1% : Highly potent, rapid relief anti-eosinophilic effect

Pemirolast 0.1 % : Twice or four times daily dosing,

effective for itch

Side effects Burning , stinging and discomfort upon

installation Do not produce immediate relief of

symptoms Headache , rhinitis , cold & flu

symptoms

Dual-action antihistamine/mast cell stabilizer Have mast cell antagonism & H1 antagonism

Olopatadine 0.1% Highly effective, rapid onset & atleat 8 hrs of action . Used twice daily

Olopatidine 0.2% used once daily

Side effects - burning ,stinging , foreign body sensation , dry eye , hypermia , keratitis , eyelid edema , pruritis , asthenia , rhinitis , sinusitis

Ketotifen 0.025% twice daily

Side effects – conjunctival injection , headache , rhinitis

Azelastine0.05% Approved for itch

Non steroidal anti -inflammmatory drugs

Block the cyclo-oxygenase pathway, limiting production of prostaglandins and thromboxanes

Analgesic. Can be used for acute attacksCommon drugs used Diclofenac 0.1% Ketorolac 0.5% (Acular ) Ketorolac 0.4% (Acular LS), Ketorolac 0.45% (Acuvail )

Nepafenac 0.1% (Nevanac ) Bromfenac 0.09% SIDE EFFECTS

Persistent epithelial defect. Stromal infiltration. Ulceration. Thinning. Perforation.

Corticosteroids - topical Corticosteroids, the gold standard for

inflammation control, prevent the formation of arachidonic

acid, effectively block both the cyclooxygenase and lipoxygenase pathways

suppress inflammatory cell migration and fibroblast function and reduce capillary permeability

fluorometholone 0.1% , 0.25% loteprednol etabonate 0.5% , 0.2% prednisolone acetate 0.12% ,1% Dexamethasone phosphate 0.1%, Difluprednate 0.05% Rimexolone 1%

Side effects Ocular discomfort. Delayed epithelial healing. HSV flare up. Increase IOP. Posterior subcapsular cataract Ptosis Mydriasis.

Local injection. VKC. AKC.

Oral. For severe cases of AKC.

Cyclosporine Cyclosporine (cyclosporine A ) is a

selective immunosuppressant inhibits IL2 and T-cell activation. also has

an inhibitory effect on eosinophils activation.

Topical 2% drops - effective as steroid sparing drug in severe VKC and AKC.

effect is usually transient. S/E:

• Intense stinging.• Keratitis.

• Systemic CsA has been used in patients with AKC.

Newer drugs Anti IgE -- Omalizumab Decreases free IgE levels and down-regulates IgE receptors on basophils used for seasonal and perennial allergic conjunctivitis immonotherapy Long term administration of low but progressively increasing doses of the offending allergen until the evoked clinical reaction is reduced or eliminated. sublingually, nasally, bronchially, ocularly, and subcutaneously (usual route ) Recent meta-analysis showed that it is useful for allergic conjunctivitis.