Anti Inflammatory Drugs - Anti allergy drugs

Question 1

allergic eye disease

Answer 1

• acute allergic conj
• seasonal/ perennial allergic conj (CAC/PAC)
• giant papillary conj
• atopic keratoconjunctivtis
• vernal keratoconjunctivitis

Question 2

the role of mast cells in ocular allergy

Answer 2

1) antigen crosses the mucus membrane - conj is taken up by an antigen presenting cell
2) antigen presenting cell presents allergen to T helper cell
3) T helper cell produces a series of cytokines (interleukins) which then induce an antibody reponse - b cell produces antibodies IgE which bind to surface of mast cells
4) first contact = px asymptomatic, secont contact leads to mast cell degranulation
5) cross linking of adj IgE molecules leads to calcium influx which leads to mast cell degranulation

Question 3

anti allergy drugs

Answer 3

• anti histamines
• mast cell destabilisers
• corticosteroids
• NSAIDs
• vasoconstrictors

Question 4

anthistamines

Answer 4

• available in topical and systemic forms - includemany OTC preparations
• systemic antihistamines used predominantly to treat symptoms of hay fever eg diphenhydramine (older gen AH which can have sedative side effects), cetirizine
• topical antihistamines predominantly used to treat SAC and PAC
• newer antihistamines posses antihistamine and mast cell stabilising properties

Question 5

available topical antihistamine preparations

Answer 5

1) Antazoline (P) - Otrivine Atistin (also containes xylometazoline) take 4 times a day - not licensed for <12 and people with cv disease
2) Azelastine (POM)* - optilast
3) Epinastine (POM)* - relestat
4) Ketotifen (POM)* - zaditen
5) Olopatadine (POM)* - opatanol
* dual action - antihistamine and mast cell stablisers, use twice a day

Question 6

Topical mast cell stabilisers

Answer 6

• block calcium influx into mast cell membrane preventing degranulation
• may take 7-14 days to produce symptomatic relief
• effective in the management of moderate to severe allergic eye disease eg SAC, GPC, VKC

Question 7

available mast cell stabilisers

Answer 7

1) sodium cromoglicate (GSL/POM/P) - opticrom
2) lodoxamide (POM) - alomide
3) nedocromil sodium (POM) - raptil - discontinued 2018

Question 8

NSAID

Answer 8

• diclofenac sodium (POM) is licensed for SAC

- well tolerated and produces symptomatic relief within 30 mins of instillation

Question 9

vasoconstrictors (OTC)

Answer 9

• sympathomimetic drugs
• cause constriction of conjunctival blood vessels by direct stimulation of alpha adrenoceptors on the conj vasculature with a decrease in conj hyperaemia and oedema
• more cosmetic then therapeutic relief
• can get rebound hyperaemia

Question 10

available vasoconstrictors

Answer 10

1) Xylometazoline - eg otrivine antistin
2) naphazoline -eg murine, optrex clear eyes
3) phenylephrine - currently no available preparation in the uk