anti-inflammatory, anti allergy, anti-infective drugs, dry eye preparations Flashcards
What is primary eye care?
the provision of first contact care for all ophthalmic conditions and the follow-up, preventive and rehabilitative care of selected ophthalmic conditions
Who is part of the primary eye care workforce?
optometrists, ophthalmologists, GP’s, A&E doctors, community pharmacists
what eye preparations can pharmacists supply?
several OTC eye preparations like chloramphenicol, propamidine, anti-allergy agents, lubricants
Give a summary of GOC rules relating to injury or disease of the eye?
2005 Rule 6
optometrist can decide not to refer at their description but must record:
-sufficient description of injury/disease
-reason for not referring
-details of advice/treatment given to px
-inform px’s GP
what optometrist enhanced services are available?
glaucoma repeat measures
glaucoma referral refinement
PEARS (primary eye care assessment and referral service)
MECS (minor eye conditions service)
CUES (covid-19 urget eyecare service)
what are the requirements for joining MECS?
optometrist training: distant learning modules, practical assessment, HES casualty day placement, accreditation
clinical equipment should be available: slit lamp, Volk, contact tonometer (Goldman’s and Perkins), visual field capable of producing a plot, eyelash removal instruments, diagnostic medication
is MECS successful?
yes
reduces ophthalmologist referrals
cost effectiveness
high clinical safety
high px satisfaction
what is CUES?
A result of the coronavirus (COVID-19)
routine sight testing stopped temporarily and there was reduced capacity in emergency ophthalmology services
CUES was commissioned and delivered through particular optometry practices acting as urgent care hubs
what is rational prescribing?
treatment needs to be adapted depending on px and we need to be cautious of contraindications. poor prescribing less to higher costs and harm to px.
what are the steps of rational prescribing?
- Specify therapeutic objective (what do you want to achieve)
- Make an inventory of possible treatments (are no-drug treatment an alternative)
- Choose a treatment (consider efficacy, safety, suitability, and cost)
- Provide px with clear info and instructions (side effects)
- Monitor effectiveness of treatment (reviewing the px, have you got correct diagnosis, response to treatment)
what should we consider when prescribing in children?
differ in response to drug
drugs aren’t extensively tested on children so side effects not as well known
higher risk of toxicity due to reduced drug clearance and different target organ sensitivity
children have immature excretory function so greater exposure to drug.
check suitability for use in children by referring to SPC.
why is there caution when prescribing in women who are breast feeding?
drugs can cross placenta and enter treat milk
what are the rules of prescribing in pregnant women?
- Avoid unnecessary drug use and consider non-drug therapy
- Assess the benefit/risk ratio for both mother and developing baby
- Avoid all drugs in the 1st trimester whenever possible (the period of greatest risk for teratogenesis is the 3-11 weeks of pregnancy)
- Drugs given during the 2nd and 3rd trimesters may affect the growth of the foetus or functional development, or have a toxic effect on foetal tissue
what are the rules of prescribing in breastfeeding mothers?
Avoid unnecessary drug use and consider non-drug treatments first
Assess the benefit/risk ratio for both mother and infant
Avoid use of drugs known to cause serious toxicity in adults or children
Use older drugs first-line as these will have a more detailed safety history; use the lowest effective dose.
Drugs licensed for use in infants do not generally pose a hazard
why should be cautious when prescribing in the elderly?
Reduction in renal drug clearance with age. Kidneys don’t work as well.
Problem for drugs that are excreted unchanged by kidney and have a narrow therapeutic index
Diabetes and heart failure can worsen renal function
Older people have increased sensitivity to drugs, especially those acting on central nervous system
Frail elderly people can have difficulty swallowing tablets or using eye drops
Can consider compliance aids for eyedrops (for those who have arthritis)
Applies pressure to bottle to express drop, direct eye drop into eye.
what are the main types of anti-inflammatory drugs?
- corticosteroids
- non-steroidal anti inflammatory drugs (NSAIDs)
3.ciclosporin
what are corticosteroids?
naturally occurring hormones in the body produced by the adrenal gland
what are the 2 main groups of corticosteroids and what do they do?
glucocorticoids: maintain normal levels of blood glucose and promote recovery from injury
mineralocorticoids: affects sodium ion balance causing sodium re uptake and water retention so influences blood pressure
give 2 examples of corticosteroids from each group?
glucocorticoids:cortisol
mineralocorticoids:aldosterone
what hormone regulates levels of corticosteroids and where is it produced?
adrenocorticotrophic hormone (ACTH)
what are the 2 main pharmacological actions of glucocorticoids?
- anti-inflammatory and immunosuppressive effects through reduction in activity of inflammatory mediators
2.metabolic effects on carbohydrates, proteins and fat
what role do inflammatory mediators play in the inflammatory response?
vascular events: vasodilation, increased vascular permeability
cellular events: leukocytes migrate out of vascular system into tissues towards site of inflammation)
What is the action of corticosteroids?
steroid receptor is located in cytoplasm.
steroid binds to its receptor, then the steroid receptor complex moves to the cell nucleus.
In the cell nucleus the steroid receptor complex bind to glucocorticoid response elements
these elements control the transcription of genes and control the synthesis of inflammatory mediators.
how to corticosteroids reduce inflammatory mediator activity?
phospholipase A2 is an enzyme that coverts phospholipids into arachidonic acid
corticosteroids inhibit phospholipase A2
by inhibiting this enzyme, steroids reduce the synthesis of all mediators downstream from that enzyme
what are the therapeutic uses of corticosteroids?
- Anti-inflammatory effects (topical and systemic): Asthma, eczema, inflammatory bowel disease, rheumatic disease
- Replacement therapy for diseases of adrenal gland as px will have low level of corticosteroids so drug is used.
- Chemotherapy (acute leukaemia, Hodgkin’s lymphoma)
- Immunosuppression e.g. Post transplantation
what are the adverse reactions of corticosteroids?
- Impaired glucose tolerance or sometimes diabetes mellitus
- Osteoporosis (bones become brittle)
- Cushings syndrome
- Immune suppression (body more vulnerable to opportunistic infections)
what are the indications for using corticosteroids?
Used for sigh threatening conditions
* Used for the treatment of acute and chronic inflammation e.g., anterior uveitis, vernal conjunctivitis
* Used to reduce post-operative inflammation following penetrative ocular surgery. Used after cataract surgery.
* Intravitreal steroids used to treat macular oedema following retinal venous occlusion and some cases of posterior uveitis. Injections and intravitreal implants
what corticosteroid do you use for severe inflammation and why?
prednisolone acetate: penetrates deeper into tissues. much more lipid soluble than PSP (prednisolone sodium phosphate)
what corticosteroid do you use for mild inflammation?
prednisolone sodium phosphate (0.055 or 0.1%)
hydrocortisone
what are all the available corticosteroid preparations?
betamethasone
dexamethasone
fluorometholone
loteprednol
prednisolone
combined preparations with antibiotics:
betnesol N
maxitrol
tobradex
what are intravitreal corticosteroid implants used for?
ozurdex- includes dexamethasone
used for macula oedema following retinal venous occlusions and non-infectious posterior uveitis
what adverse reactions can you get from ophthalmic corticosteroids?
cataract- more likely with high dose taking for more than 1 year
raised IOP- short term use, dexamethasone more likely to raise IOP
what are NSAIDs used for?
pre operatively and post operatively
provides mild to moderate anti-inflammatory potency without side effects of corticosteroids.
how do NSAIDs reduce inflammation?
They prevent the formation of a family of compounds called eicosanoids which act as inflammatory mediators.
Principle eicosanoids are prostaglandins and leukotrienes.
eicosanoids cause vasodilation, increased IOP, miosis and macular oedema in the eye
Action of NSAID is due to inhibition of the enzyme cyclo-oxygenase (COX)
what are the indications for using NSAIDs?
- Reduction of intra-operative and post-operative ocular inflammation
- Used to reduce post-operative pain (e.g., in refractive surgery)
- Reduction of pain following corneal trauma (diclofenac sodium)
- Allergic conjunctivitis (diclofenac sodium)
- Episcleritis (off license)
what are the available NSAIDs?
diclofenac sodium
flurbiprofen
ketorolac
nepafenac
bromfenac
how does ciclosporin reduce inflammation?
used as an immunosuppressive agent following transplantation
Ciclosporin inhibits the release of cytokines from T-lymphocytes and therefore supresses the cell-mediated immune response
what is ciclosporin used to treat?
- Licensed for the treatment of severe keratitis in dry eye disease (which has not improved with ocular lubricants) (Ikervis)
- Licensed for the treatment of severe vernal keratoconjunctivitis (VKC) (Verkazia)
what are the available ciclosporin drugs?
ikervis
verkazia
summarise the allergic eye response
- Eye is susceptible to allergy as its exposed
- Majority of ocular allergies effect conjunctiva and the eyelid and cornea
- Type 1 hypersensitivity reactions mediated by mast cells
- Degranulation of mast cells release inflammatory mediators like histamine
- These mediators cause signs and symptoms of ocular allergy
what are the types of allergic eye disease?
acute allergic conjunctivitis
seasonal/perennial allergic conjunctivitis
giant papillary conjunctivitis
atopic keratoconjunctivitis
vernal keratoconjunctivits
what are the types of anti-allergy drugs?
antihistamines (topical and systemic)
mast cell stabilisers
corticosteroids (severe allergic eye disease)
NASIDs
vasoconstrictors
What is the role of mast cells in ocular allergy?
The antigen crosses the mucous membrane, the conjunctiva.
Allergen is taken up by an antigen presenting cell.
The antigen presenting cell then presents that allergen to a T-helper cell, which then produces a series of cytokines, interleukins, which then choose an antibody response.
This induces the B cell to produce antibodies.
Typically, an antibody response generates a IgG and then later IgM.
In allergic response, IgE antibodies are produced and bind to the surface of mass cell.
Following the first contact with the antigen, the patient is asymptomatic.
It’s the second exposure to the antigen that induces mass cell degranulation and every subsequent exposure.
Cross linking of adjacent IgE molecules leads to calcium influx which causes mast cell degranulation.
Pre-formed mediators: stored within mast cells, histamines
Newly formed mediators: responsible for clinical effects, prostaglandins
what are antihistamines used for?
what form can they be found in?
Widely used for treating ocular allergy and systemic allergies
Topical and systemic form (many OTC): eye drops, tablets, cream
Systemic antihistamines used to treat hay fever e.g., diphenhydramine, cetirizine
Topical antihistamines to treat SAC and PAC (seasonal, perennial)
why are newer antihistamines better?
they are dual acting with mast cell stabilising properties. Advantage is you only need to take them 2x a day.
older ones are associated with sedative effects
what are the available topical antihistamines and what is their legislation?
antazoline (P)- not licensed for u12
azelastine (POM)
epinastine (POM)
ketotifen (POM)
olopatadine (POM)
how to topical mast cell stabilisers work?
how long do they take to work?
Blocks calcium influx into mast cell membrane which is the trigger for mast cell degranulation
May take 7-14 days to produce symptomatic relief
what type of allergic eye disease are they used to manage?
seasonal allergic conjunctivitis
giant papillary C
Vernal keratoc
what are the mast cell stabilisers available and what are their legislation?
sodium cromoglicate (P/PM)
lodoxamide (POM)
nedocromil sodium (POM)
what NSAIDs can be used in allergic eye disease?
- Diclofenac sodium (POM) is licensed for seasonal allergic conjunctivitis
- Well tolerated and produces symptomatic relief within 30 minutes of instillation
what do vasoconstrictors do?
- Produced to reduce redness of the eyes
- Sympathomimetic drug: more cosmetic
- Cause constriction of conjunctival blood vessels by direct stimulation of alpha adrenoreceptors on the conjunctival vasculature
- Decreases conjunctival hyperaemia and oedema
why are vasoconstrictors not commonly used in allergic eye disease?
can get rebound hyperaemia
