anti-inflammatory, anti allergy, anti-infective drugs, dry eye preparations Flashcards
(130 cards)
1
Q
What is primary eye care?
A
the provision of first contact care for all ophthalmic conditions and the follow-up, preventive and rehabilitative care of selected ophthalmic conditions
2
Q
Who is part of the primary eye care workforce?
A
optometrists, ophthalmologists, GP’s, A&E doctors, community pharmacists
3
Q
what eye preparations can pharmacists supply?
A
several OTC eye preparations like chloramphenicol, propamidine, anti-allergy agents, lubricants
4
Q
Give a summary of GOC rules relating to injury or disease of the eye?
A
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
5
Q
what optometrist enhanced services are available?
A
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)
6
Q
what are the requirements for joining MECS?
A
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
7
Q
is MECS successful?
A
yes
reduces ophthalmologist referrals
cost effectiveness
high clinical safety
high px satisfaction
8
Q
what is CUES?
A
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
9
Q
what is rational prescribing?
A
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.
10
Q
what are the steps of rational prescribing?
A
- 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)
11
Q
what should we consider when prescribing in children?
A
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.
12
Q
why is there caution when prescribing in women who are breast feeding?
A
drugs can cross placenta and enter treat milk
13
Q
what are the rules of prescribing in pregnant women?
A
- 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
14
Q
what are the rules of prescribing in breastfeeding mothers?
A
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
15
Q
why should be cautious when prescribing in the elderly?
A
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.
16
Q
what are the main types of anti-inflammatory drugs?
A
- corticosteroids
- non-steroidal anti inflammatory drugs (NSAIDs)
3.ciclosporin
17
Q
what are corticosteroids?
A
naturally occurring hormones in the body produced by the adrenal gland
18
Q
what are the 2 main groups of corticosteroids and what do they do?
A
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
19
Q
give 2 examples of corticosteroids from each group?
A
glucocorticoids:cortisol
mineralocorticoids:aldosterone
20
Q
what hormone regulates levels of corticosteroids and where is it produced?
A
adrenocorticotrophic hormone (ACTH)
21
Q
what are the 2 main pharmacological actions of glucocorticoids?
A
- anti-inflammatory and immunosuppressive effects through reduction in activity of inflammatory mediators
2.metabolic effects on carbohydrates, proteins and fat
22
Q
what role do inflammatory mediators play in the inflammatory response?
A
vascular events: vasodilation, increased vascular permeability
cellular events: leukocytes migrate out of vascular system into tissues towards site of inflammation)
23
Q
What is the action of corticosteroids?
A
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.
24
Q
how to corticosteroids reduce inflammatory mediator activity?
A
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
25
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
26
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)
27
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
28
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)
29
what corticosteroid do you use for mild inflammation?
prednisolone sodium phosphate (0.055 or 0.1%)
hydrocortisone
30
what are all the available corticosteroid preparations?
betamethasone
dexamethasone
fluorometholone
loteprednol
prednisolone
combined preparations with antibiotics:
betnesol N
maxitrol
tobradex
31
what are intravitreal corticosteroid implants used for?
ozurdex- includes dexamethasone
used for macula oedema following retinal venous occlusions and non-infectious posterior uveitis
32
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
33
what are NSAIDs used for?
pre operatively and post operatively
provides mild to moderate anti-inflammatory potency without side effects of corticosteroids.
34
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)
35
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)
36
what are the available NSAIDs?
diclofenac sodium
flurbiprofen
ketorolac
nepafenac
bromfenac
37
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
38
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)
39
what are the available ciclosporin drugs?
ikervis
verkazia
40
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
41
what are the types of allergic eye disease?
acute allergic conjunctivitis
seasonal/perennial allergic conjunctivitis
giant papillary conjunctivitis
atopic keratoconjunctivitis
vernal keratoconjunctivits
42
what are the types of anti-allergy drugs?
antihistamines (topical and systemic)
mast cell stabilisers
corticosteroids (severe allergic eye disease)
NASIDs
vasoconstrictors
43
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
44
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)
45
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
46
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)
47
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
48
what type of allergic eye disease are they used to manage?
seasonal allergic conjunctivitis
giant papillary C
Vernal keratoc
49
what are the mast cell stabilisers available and what are their legislation?
sodium cromoglicate (P/PM)
lodoxamide (POM)
nedocromil sodium (POM)
50
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
51
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
52
why are vasoconstrictors not commonly used in allergic eye disease?
can get rebound hyperaemia
53
what vasoconstrictors available?
xylometazoline
naphazoline
phenylephrine- not available in UK
54
what OTC allergy medicine can be supplied by optometrists?
antazoline
sodium cromoglicate - P/POM
55
what do anti-infective medication exploit?
differences exist between human cells and bacterial cells (differences in cell membranes , bacteria have unique cell wall, bacteria have different DNA mechanism and protein synthesis)
drugs have selective toxicity (toxic only against bacteria)
56
what antibacterial drugs affect cell wall synthesis?
penicillins
cephalosporins
57
what antibacterial drugs affect bacterial cell membrane?
polymyxin B
Propamidine
58
what antibacterial drugs affect bacterial protein synthesis?
aminoglycosides
tetracyclines
chloramphenicol
fusidic acid
59
what antibacterial drugs affect bacterial DNA synthesis?
fluoroquinolones
60
what antibacterial drug affects bacterial metabolism?
sulphonamides
61
what are the general considerations when prescribing antibiotics?
Broad specificity or narrow specificity (selective against a particular organism)
used as single agents or in combination
How well does antibiotic penetrate the tissue (superficial or deep infection)
Route of administration (most forms in ophthalmology are topical, ointments and eyedrops)
Side effects: tolerability, safe to use in pregnancy/lactation
Consider antibiotic sensitivity
62
what is the Kirby-Bauer test?
A paper disc, which has been impregnated with various antibiotics, is placed on top of the culture
Zones of diameter are read around each antibiotic disc and compared with standard values to judge whether the zone size represents a sensitive, intermediate, or resistant isolate.
63
what anti-infective are available to optometrists?
chloramphenicol
fusidic acid
propamidine
polymyxin B-discontinued in UK
64
what are the formulations of chloramphenicol and dosage?
Formulations
1. Chloramphenicol 0.5% eyedrops
2. Chloramphenicol 1% ophthalmic ointment
3. Minims chloramphenicol 0.5% unit eye drops
Dose
1 drop every 2 hours for 48 hours
Then every 4 hours for 5 days
A week of treatment
65
what is medical legislation of chloramphenicol?
Available as POM and P medicine.
* P version is licensed for acute bacterial conjunctivitis
* POM version for licenced for prophylactic use (corneal body abrasion, corneal foreign body, superficial infection-infective bleph, BC)
66
is chloramphenicol a board or narrow spectrum antibiotic?
Broad spectrum antibiotic-not effective against pseudomonas which can cause bacterial keratitis.
67
What is the mode of action of chloramphenicol ?
* Inhibition of bacterial protein synthesis
* Chloramphenicol binds to peptidyl transferase (located on bacterial ribosome)
* By blocking the enzyme, it stops new amino acids to join peptide chain
Bacteriostatic-slows bacterial growth
May be bactericidal for some species at a high concentration-kills bacteria
68
what are the side effects of chloramphenicol?
Systemic use is linked with aplastic anaemia, bone marrow suppression, grey baby syndrome.
Extremely unlikely with topical application
69
what is the bacterial resistance of chloramphenicol like?
low
70
what type of bacteria are more likely to cause bacterial conjunctivitis?
Haeomphilus-more common in children
pseudomonas-very rare
more common: stapha, staphe, strep
71
what is the medical legislation of fusidic acid?
POM
72
what is the spectrum of fusidic acid like?
narrow
affective against broad range of gram + organisms particularly staphylococcus
73
how does fusidic acid kill bacteria?
bacteriostatic-slows bacterial growth
can be bactericidal at high concentration
74
what is fusidic acid used to treat?
Licensed for treatment of bacterial conjunctivitis
Off licence use: prophylaxis following corneal abrasion, blepharitis
75
why is fusidic acid not used in children?
* Not appropriate agent for bacterial conjunctivitis n children as its infective against gram negative bacteria like H influenzae (most common cause of BC in children)
76
what formulations and dosage are there for fusidic acid?
Formulation
Fusidic acid 1% modified release eyedrops POM (viscous gel, like an ointment when it comes out of the tube)
DOSE
2x daily (less than chloramphenicol due to more contact time with ocular surface)
77
describe pharmacokinetics of fusidic acid
very viscous-can get detectable levels of it up to 8 minutes after instillation
doesn't penetrate tissues readily
78
what is the efficacy of fusidic acid
* Good sensitivity against staphylococcus species including MRSA
* Haemophilus and pseudomonas are resistant to it
79
compare the cost of chloramphenicol compared to fusidic acid
chloramphenicol: £5.41 drops
fusidic acid: £35
80
what are the age restrictions for fusidic acid and chloramphenicol?
FA- more than 1 months, safer in pregnancy
CP- POM-more than 1 month
P-more than 2 years
81
what is the medical legislation of polymyxin B?
P
can get OTC
82
how does polymyxin B kill bacteria?
Polymyxin B attaches to and interferes with the functioning of cell membrane in gram-negative bacteria
Bacitracin: inhibits synthesis of cell wall of gram-positive bacteria
broad spectrum
83
what formulations of polymyxin B were available?
* Polyfax eye ointment (combo of polymyxin B and bacitracin): broad range of antibiotic activity, including Pseudomonas aeruginosa.
* Polyfax was discontinued in October 2012
84
what is the medical legislation of propamidine?
what is it classified as?
what is it effective against?
P medicine. Can get OTC.
Not antibiotic, it’s a disinfectant
Classified as diamidine
Effective against gram positive, less against gram negative
85
what preterites does propamidine have?
brolene eyedrops
golden eye ointment
86
what other anti-bacterials are used in ophthalmology?
fluoroquinolones
aminoglycosides
tetracyclines
87
what is the main indication for using fluoroquinolones?
bacterial keratitis
88
what is fluoroquinolones effective against?
Effective against gram negative bacteria like pseudomonas (more likely to cause BK)
89
how does fluoroquinolones kill bacteria?
what type of spectrum does it have?
* Work by inhibiting bacterial DNA synthesis
* Broad spectrum (gram – and gram +)
90
what types of fluoroquinolones are available?
Ofloxacin
Ciprofloxacin
Levofloxacin-newer, used more readily due to less bacterial resistance
Moxifloxacin- newer
91
what type of spectrum do aminoglycosides have?
how do they inhibit bacteria?
what is their main side effect?
what types are available?
Broad spectrum (effective against gram – and gram+)
Inhibits protein synthesis
Bactericidal
Main side effect: Epithelial toxicity in predisposed patients
Gentamycin
Neomycin
Tobramycin
92
How are tetracyclines delivered?
How do they kill bacteria?
what spectrum do they have?
what is the main indication of use?
What are they used more for?
what ones are available?
Antibiotics are delivered systemically (tablets)
Inhibits bacterial protein synthesis by blocking attachment of the transfer RNA-amino acid to the ribosome.
Decreases bacterial load on lid margins
Broad spectrum
Main indication: treatment of meibomian gland disease
anti-inflammatory properties
doxycycline
minocycline
93
what is azithromycin used for?
* Standard drug for treated trachoma in parts of the world as its effective against chlamydia
* Licensed for acute bacterial conjunctivitis and chlamydia trachomatis
* Off licence use in blepharitis
94
what is the dosage of Azithromycin for AMC?
* Unit dose preparation-preservative free
* Weeks unit dose supply for ABC
95
what does cytomegalovirus present as in the eye?
necrotising retinitis
96
what can VSZ virus present as in the eye?
* Ophthalmic shingles: risk of corneal involvement which is sight threatening
97
what can HSV present as in the eye?
thin dendritic ulcers
98
what anti-viral drugs are available?
acyclovir
ganciclovir
99
what is acyclovir used for/available as?
How does this drug stop the virus?
Available for cold sores as topical formulation
Available as oral medication
Only available ophthalmic formulation was discontinued in 2018
Enters the cell and is converted to acyclovir monophosphate by HSV enzyme called thymidine kinase (TK).
Enzyme adds 2 more phosphates to from active drug acyclovir triphosphate.
This drug competes with 2-deoxyyguanosine triphosphate as a substrate for viral DNS polymerase.
This inhibits viral DNA synthesis
100
what is ganiclovir used for?
what is it available as?
What is its trade name?
treatment of HSK
eye Gell
Slow-release ocular implants of ganciclovir are available to treat sight threatening CMD. Inserted into eye surgically
virgan
101
what are the 2 parts of acanthamoeba?
mobile trophozoites
dormant cysts
102
what is the treatment for Acanthamoeba?
what is the dosage?
Propamidine 0,1% and polyhexamethylene biguanide (PHMB) 0.02%
or
Chlorhexidine 0.02%
Administered hourly day and night for 2 days then reduce dose as condition improves
PHMB and chlorhexidine have shown activity against cyst form
103
what are ocular lubricants classified as?
medical devices
* May limit their availability on NHS prescriptions
104
what are the indications for using ocular lubricants?
dry eye
any ocular discomfort
recurrent corneal erosions (epithelium fails to heal completely)
105
how do you manage mild dry eye?
* Educating regarding condition
* Modify local environment
* Nutritional device (include oral essential fatty acid consumption)
* Modification/elimination of systematic and topical medication
* Ocular lubricants
* Lid hygiene and warm compresses
106
how do you manage moderate dry eye?
§ Non-preserved lubricants
§ Tear conservation e.g. punctal plugs
§ Non-medicated ointment at night
§ Topical antibiotics for anterior blepharitis (if present)
§ Oral antibiotics e.g tetracyclines
§ Topical immunomodulatory drugs e.g. ciclosporin
107
What are the limitations of ocular lubricants in dry eye disease?
Formulation cannot replace complexity of natural tears
Administered intermittently rather than continuously as with natural tears. Therefore, formulated to increase their contact time e.g., mucoadhesive polymers
Choice of therapy is determined by the severity of the condition considering the lifestyle and dexterity of the patient. Done to trial and error.
The presence of preservatives in artificial tears can compromise the ocular surface following prolonged use. Relevant to multi-dose preparations.
108
What are the tear replacement approaches?
1. Aqueous substitutes (contain viscosity enhancers)
2. Biological tear substitutes (act on lacrimal secretion system e.g., stimulate lacrimal gland to produce tears)
3. Other agents
109
What type of aqueous substitutions are available?
* Cellulose esters
* Carbomers
* Polyvinyl alcohol
* Sodium hyaluronate
* Hydroxypropyl (HP) Guar
110
why are mucoadhesive properties important for ocular lubricants?
what are the side effects of viscous agents?
what viscous agent has the highest contact time?
These properties increase contact time with the ocular surface
blurry vision as you administer eye drops, eyelid can become sticky, can form deposits as it dries out on lid margins
Sodium carboxymethylcellulose has a very high contact time
111
describe the nonnewtonian behaviour of the tear film
when shear rates (force applied across a surface) are low, the viscosity of the tears are high. Reflects situation of an open eye.
When eye moves (blinking), shear rate is high and viscosity falls.
112
what are cellulose esters?
what is good about them?
what is bad about them?
what types are available?
what formulations are they available as?
Viscoelastic polysaccharides
Good retention time on ocular surface
Can cause blurry vision and crusting on eyelids due to increased contact time
Hydroxypropyl methyl cellulose (Hypromellose), methylcellulose, carboxymethylcellulose (Carmellose)
Available in multi-dose formulation and single dose
113
what 2 types of carbomers are available?
what are they?
what is good about them?
what is bad about hem?
What formulation is available?
carbomer 980, carbomer 940
Synthetic polymer
Good retention time on ocular surface
Good viscosity when eyes open, shear thin during blinking (non-Newtonian shear thinning)
Tends to blur vision
gel tears, comes in a tube
114
what is polyvinyl alcohol?
what is good/bad about it?
what formulation is it available as?
Synthetic polymer
Lower viscosity so no impact on vision but shorter retention time
Beneficial in mucin and lipid deficiency
liquifilm tears
115
What is sodium hyaluronate?
what is good/bad about it?
Naturally occurring polymer in the body: mucopolysaccharide
*Viscous formulation: good retention time
*Exhibits non-Newtonian shear thinning properties
Tends to blur vison
116
Which company developed hydroxypropyl-guar?
how does this work?
systane
Increases in viscosity after contact with ocular surface.
pH of ocular surface causes a chemical reaction. HP gaur binds to ocular surface and cross links with borate ions in the solution forming a network with a gel like consistency.
117
What are the indications for giving a px preservative free eyedrops?
* Previous sensitivity to a preservative
* Immediately after invasive surgery
* Frequently using lots of muti dose preparations (3/12 treatment, 6 times per day)
* Ocular surface disease
* Soft Contact lenses
118
what preservative are contact lenses not compatible with?
why?
benzalkonium chloride
Preservative is taken up by contact lenses and released slowly
Elevates preservative contact time
Particularly true in high water contact lenses as they absorb greater quantities.
119
What are the newer ophthalmic preservatives produced to reduce ocular toxicity?
Purite: Stabilized oxychloro-complex dissipates into water and sodium chloride on exposure to light (once outside the bottle)
Sodium perborate: converts into water and oxygen on instillation
SofZia: modified into harmless elements on instillation
Polyquaternium: less toxic than BAK. Common in multidose contact lens care products
120
how do unit dose preservative systems work?
how do multi-dose preservative systems work?
minims for single use-more expensive
Valve system within the neck of the bottle prevents air from getting in the bottle so reduced risk of microbial contamination
Cost effective
121
give examples of multi-dose preservative free formulations available
hycoscan 0.1% hyaluronate
hycoscan extra 0.2% hyaluronate
hylotear 0.1% hyaluronate
hyloforte 0.2% hyaluronate
hyabak 0.15% hyaluronate
122
in which px is lubricating eye ointments used?
how do they work?
when are they used?
what formulations are there?
severe dry eye
reoccur ant epithelial erosions
contributes to rebuild the lipid layer.
very viscous when comes out the tube but melts at the temperature of ocular surface and spreads across the eye
used at night due to blurry vison.
liquid paraffin
lipid layer
lacrilube, vit a pos
123
what is filamentary keratitis?
how can it be treated?
Dry eye patients may develop filamentary keratitis
Mucus filaments attach firmly to the surface of the eye
Acetylcysteine 5-10% e.g., llube (POM)
Dissolved mucous filaments by breaking disulphide bonds
Stinging sensation on initialisation
124
how do liposomal sprays work?
Aqueous suspension of phospholipid containing lysosomes
Spray the formulation on closed eyelids
Works its way into lid margins and spread into tears
Lipid layer replacement to reduce evaporation of tear film in evaporative dry eye
125
What is used in treatment of keratitis caused any dry eye ?
Ikervis(1mg/ml ciclosporin) has been approved for treatment of severe keratitis in the UK
126
what is autologous serum?
how is it made?
Using px own serum witch includes many things beneficial for tear film
Used in severe dry eye
1.a sample of px own blood is taken
2.blood is centrifuged to get serum
3.small amount of serum is put in dropper bottles. Saline is added to produce a 20% dilute serum solution.
4.can’t add preservatives because you can get toxicity in an already compromised ocular surface. Short term life and need to be refrigerated.
127
what are the types of tear stimulation approaches?
Several topical pharmacological agents that stimulate aqueous, mucin and /or lipid secretion are commercially available in some countries or under development
Aqueous secretalogues e.g., Diquafosol tetrasodium
Mucin secretalogues e.g., Rebamipide
Lipid secretalogues e.g., IGF-1, androgens
128
what is the prescribing guidance in mild dry eye
hypormellose 0.3% eyedrops
carbomer 980 0.2% gel
carmellose 0.5% eyedrops
129
what is the prescribing guidance in moderate dry eye
carbomer 980 0.2% gel
carmellose 0.5% SDU
multi dose preservative free: 0.1% sodium hyaluronate drops
130
what is the prescribing guidance for severe dry eye
ophthalmic lubricating ointments
multidose preservative free: 0.2% sodium hyaluronate
may refer to specialist
